Bio and Gchem question practice?

[Dencology]

14. which of the following do plant cells possess that animal cells do not?

a.vacuoles
b.cell membranes
c.chloroplasts
d.roots
e.mitochondria

15. Which of the following best describes the enzymes that catalyzes the conversion of glucose into glucosephosphate?

• carbohydrate
• lipid
• polypeptide chain
• nucleic acid
• amino acid

16. which type of transport across the cell memebrne does not utilize a carrier molecule?

• simple diffusion
• somosis
• receptor-mediated endocytosis
• active transport

17. which of the following statements best describes a difference between the endocrine and nervous system?

• the nervous system is involved in homeostasis while the endocrine system is not.
• products of the endocrine system travel in the blood while nervous signals travel though neurons.
• Nerves produce hormones and endocrine glands produce nerotransmitters.
• Tissues in the endocrine system are myelinated while those in the nervous system are not.
• The endocrine system uses chemicals, and the nervous system does not.

18. what type of reaction in involved in the assembly of peptiede bond?

• condensation rxn
• hydrolysis rxn
• catabolic rxn
• fermentation rxn
• metabolic rxn

19. genetic recombination during meiosis results from

• synapsis
• crossing over
• linkage

20. the functional unit of vertebrate skeletal muscle consists of

• one muscle fiber and the motor end plate.
• An entire muscle
• A single motor neuron and the group of muscle cells innervated by its anon.
• All of the muscle fibers linked by a spinal nerves
• A group of myofibrils and their myofilaments

21. at low temp and high pressures, the measured pressure of a gas is

• less than the calculated pressure, because intermolecular forces reduce the avg. force of the collisions with a unit area of the container.
• Less than the calculated pressure, because the avg. size of the gas molecules increase
• Less than the calculated pressure, because the avg. molecular speed increase.
• Greater than the calculated pressure, because the avg. molecular speed increase.
• Greater than the calculated pressure, because intermolecular forces increase the frequency of the collisions with a unit area of the container.

22. a 0.10 gram sample of gas occupies 110mL at 100 C and 0.9 atm. What is the molecular weight?
(just set up the calculation)

Guys I thought we do the following calculation:

PV=nRT for n we can right mass/molecular weight so

PV=(mass/molecular weight) RT and here we just substitute P and V for MW so we get

MW = (mass)(R)(T)/PV which would be MW= (0.10)(0.0821)(373)/(0.9)(.110) is this right?

23. a substance is nonconducting in both the solid and liquid phases. It is hard at room temp but becomes soft enough when heated to be molded into various shapes. It is not water soluble. This substance would be characterized best by which of the following?

• ionic
• metallic
• catalytic
• isotopic
• polymeric

my answer is E. what do you say?

24. two hundred grams of a hydrogen halid is added to a liter of water. If the boiling point of the solution is 102.5 C, what is the identity of the halide? Kb=0.51c/m

• fluoride
• chloride
• bromide
• iodide
• astatide

25. one mole of helium at STp is heated to 273 C. if the pressure doubles as a result, find the volume occupied by the heated gas.

• 5.6L
• 11.2L
• 22.4L
• 67.2L
• 89.6L

My answer is B. what do you say?

26. which of the following reagents would increase the solubility of calcium fluoride?

• HF
• HCl
• CaCl2
• NaF
• CH3CH2OH

My answer is B. what is yours?

27. Which of the following properties increases with atomic number in group 15?

• oxidation state
• ionization energy
• electronegativity
• electron affinity
• atomic radius

my ans. is c. but I am not sure!

28. a 147 gram sample of K2Cr2 O7 (294.2g/mol) contains:

• 2 mole of potassium
• 104.0gram of chromium
• 2.5 mole of oxygen
• 1 mole of molecules
• 5.5 mole of atoms

---

Members don't see this ad.

 

[PooyaH]

I haven't finished studying Bio so I'm not gonna say anything lol although most of them aren't that hard. But I can talk about GC #22:

V2 = V1 (P1/P2)(T2/T1) which you derive from the original formula PV = nRT
So compare the scenario you have to STP:

V2 = (.11L)(.9atm/1atm)(273K/373K)
V2 = 0.073L
Density = .10g / 0.073L = 1.37 g/mol
M.W. = (1.37 g/mol)(22.4 L/mol) = 30.7 mol which is the same thing as you got! lol but a different approach! lol

 

[Mstoothlady2012]

14. which of the following do plant cells possess that animal cells do not?

a.vacuoles
b.cell membranes
c.chloroplasts
d.roots
e.mitochondria

15. Which of the following best describes the enzymes that catalyzes the conversion of glucose into glucosephosphate?

• carbohydrate
• lipid
• polypeptide chain
• nucleic acid
• amino acid

the answer choices don't make sense to me!!!

16. which type of transport across the cell memebrne does not utilize a carrier molecule?

• simple diffusion
• osmosis
• receptor-mediated endocytosis
• active transport

17. which of the following statements best describes a difference between the endocrine and nervous system?

• the nervous system is involved in homeostasis while the endocrine system is not.
• products of the endocrine system travel in the blood while nervous signals travel though neurons.
• Nerves produce hormones and endocrine glands produce nerotransmitters.
• Tissues in the endocrine system are myelinated while those in the nervous system are not.
• The endocrine system uses chemicals, and the nervous system does not.

18. what type of reaction in involved in the assembly of peptiede bond?

• condensation rxn
• hydrolysis rxn
• catabolic rxn
• fermentation rxn
• metabolic rxn

19. genetic recombination during meiosis results from

• synapsis - don't these choices mean same thing?
  
• crossing over
• linkage

20. the functional unit of vertebrate skeletal muscle consists of

• one muscle fiber and the motor end plate.
• An entire muscle
• A single motor neuron and the group of muscle cells innervated by its anon.
• All of the muscle fibers linked by a spinal nerves
• A group of myofibrils and their myofilaments

21. at low temp and high pressures, the measured pressure of a gas is

• less than the calculated pressure, because intermolecular forces reduce the avg. force of the collisions with a unit area of the container.
• Less than the calculated pressure, because the avg. size of the gas molecules increase
• Less than the calculated pressure, because the avg. molecular speed increase.
• Greater than the calculated pressure, because the avg. molecular speed increase.
• Greater than the calculated pressure, because intermolecular forces increase the frequency of the collisions with a unit area of the container.

22. a 0.10 gram sample of gas occupies 110mL at 100 C and 0.9 atm. What is the molecular weight?
(just set up the calculation)

Guys I thought we do the following calculation:

PV=nRT for n we can right mass/molecular weight so

PV=(mass/molecular weight) RT and here we just substitute P and V for MW so we get

MW = (mass)(R)(T)/PV which would be MW= (0.10)(0.0821)(373)/(0.9)(.110) is this right? Looks right to me

23. a substance is nonconducting in both the solid and liquid phases. It is hard at room temp but becomes soft enough when heated to be molded into various shapes. It is not water soluble. This substance would be characterized best by which of the following?

• ionic
• metallic
• catalytic
• isotopic
• polymeric

my answer is E. what do you say? no clue! I am really bad at these type of gchem "conceptual" questions.

24. two hundred grams of a hydrogen halid is added to a liter of water. If the boiling point of the solution is 102.5 C, what is the identity of the halide? Kb=0.51c/m

• fluoride
• chloride - I am gettin gMW = 40.8. I guess Cl is the closest
  
• bromide
• iodide
• astatide

25. one mole of helium at STp is heated to 273 C. if the pressure doubles as a result, find the volume occupied by the heated gas.

• 5.6L
• 11.2L
• 22.4L
• 67.2L
• 89.6L

My answer is B. what do you say?

26. which of the following reagents would increase the solubility of calcium fluoride? not sure about this one - may be C?

• HF
• HCl
• CaCl2
• NaF
• CH3CH2OH

My answer is B. what is yours?

27. Which of the following properties increases with atomic number in group 15? group 15??? I think you made a typo here

• oxidation state
• ionization energy
• electronegativity
• electron affinity
• atomic radius

my ans. is c. but I am not sure!

answers above

 

[osimsDDS]

14. which of the following do plant cells possess that animal cells do not?

a.. .vacuoles
b.. .cell membranes
c.. .chloroplasts
d.. .roots
e.. .mitochondria

15. Which of the following best describes the enzymes that catalyzes the conversion of glucose into glucosephosphate?

• carbohydrate
• lipid
• [B]polypeptide chain[/B]
• nucleic acid
• amino acid

16. which type of transport across the cell memebrne does not utilize a carrier molecule?

• simple diffusion
• somosis
• receptor-mediated endocytosis
• active transport

17. which of the following statements best describes a difference between the endocrine and nervous system?

• the nervous system is involved in homeostasis while the endocrine system is not.
• products of the endocrine system travel in the blood while nervous signals travel though neurons.
• Nerves produce hormones and endocrine glands produce nerotransmitters.
• Tissues in the endocrine system are myelinated while those in the nervous system are not.
• The endocrine system uses chemicals, and the nervous system does not.

18. what type of reaction in involved in the assembly of peptiede bond?

• condensation rxn
• hydrolysis rxn
• catabolic rxn
• fermentation rxn
• metabolic rxn

19. genetic recombination during meiosis results from

• synapsis
• crossing over
• linkage

20. the functional unit of vertebrate skeletal muscle consists of

• one muscle fiber and the motor end plate.
• An entire muscle...isnt a functional unit the bigest part...might be wrong
• A single motor neuron and the group of muscle cells innervated by its anon.
• All of the muscle fibers linked by a spinal nerves
• A group of myofibrils and their myofilaments

21. at low temp and high pressures, the measured pressure of a gas is

• less than the calculated pressure, because intermolecular forces reduce the avg. force of the collisions with a unit area of the container.
• Less than the calculated pressure, because the avg. size of the gas molecules increase
• Less than the calculated pressure, because the avg. molecular speed increase.
• Greater than the calculated pressure, because the avg. molecular speed increase.
• Greater than the calculated pressure, because intermolecular forces increase the frequency of the collisions with a unit area of the container.

22. a 0.10 gram sample of gas occupies 110mL at 100 C and 0.9 atm. What is the molecular weight?
(just set up the calculation)

Guys I thought we do the following calculation:

PV=nRT for n we can right mass/molecular weight so

PV=(mass/molecular weight) RT and here we just substitute P and V for MW so we get

MW = (mass)(R)(T)/PV which would be MW= (0.10)(0.0821)(373)/(0.9)(.110) is this right? you are correct...thats how i would do it!!!

23. a substance is nonconducting in both the solid and liquid phases. It is hard at room temp but becomes soft enough when heated to be molded into various shapes. It is not water soluble. This substance would be characterized best by which of the following?

• ionic
• metallic
• catalytic
• isotopic
• polymeric

my answer is E. what do you say?

24. two hundred grams of a hydrogen halid is added to a liter of water. If the boiling point of the solution is 102.5 C, what is the identity of the halide? Kb=0.51c/m

the basic eequation is bp elevation: dT=(m)(kb)(i), since its a hydrogen halid (HCl for example it will dissociate into 2 molecules) because we are talking about colligative properties...so the equation will look like this: 102.5-100=(200g/MW)(.51)(2)...you get 80.1 or something like that and its closes to Br-

• fluoride
• chloride
• bromide
• iodide
• astatide

25. one mole of helium at STp is heated to 273 C. if the pressure doubles as a result, find the volume occupied by the heated gas.

• 5.6L
• 11.2L
• 22.4L...i calculated v2=v1(p1/p2)(T2/T1)...the pressure increase would cancel the temperature increase and you would be left with the same volume at STP which is 22.4L, hope thats right haha
• 67.2L
• 89.6L

My answer is B. what do you say?

26. which of the following reagents would increase the solubility of calcium fluoride?

• HF
• HCl
• CaCl2
• NaF
• CH3CH2OH...why cant it be this one?

My answer is B. what is yours?

27. Which of the following properties increases with atomic number in group 15?

• oxidation state
• ionization energy
• electronegativity
• electron affinity
• atomic radius...its group 15 not row 15 so it must be going down the group so it must be atomic radius

my ans. is c. but I am not sure!

Nice test

 

[Glycogen]

14. which of the following do plant cells possess that animal cells do not?

a.vacuoles
b.cell membranes
c.chloroplasts
d.roots
e.mitochondria

15. Which of the following best describes the enzymes that catalyzes the conversion of glucose into glucosephosphate?

• carbohydrate
• lipid
• polypeptide chain (since enzymes are protein)
  
• nucleic acid
• amino acid

16. which type of transport across the cell memebrne does not utilize a carrier molecule?

• simple diffusion
• somosis (I think this is only for water)
  
• receptor-mediated endocytosis
• active transport

17. which of the following statements best describes a difference between the endocrine and nervous system?

• the nervous system is involved in homeostasis while the endocrine system is not.
• products of the endocrine system travel in the blood while nervous signals travel though neurons.
• Nerves produce hormones and endocrine glands produce nerotransmitters.
• Tissues in the endocrine system are myelinated while those in the nervous system are not.
• The endocrine system uses chemicals, and the nervous system does not.

18. what type of reaction in involved in the assembly of peptiede bond?

• condensation rxn
• hydrolysis rxn
• catabolic rxn
• fermentation rxn
• metabolic rxn

19. genetic recombination during meiosis results from

• synapsis
• crossing over
• linkage

20. the functional unit of vertebrate skeletal muscle consists of

• one muscle fiber and the motor end plate.
• An entire muscle
• A single motor neuron and the group of muscle cells innervated by its anon.
• All of the muscle fibers linked by a spinal nerves
• A group of myofibrils and their myofilaments

21. at low temp and high pressures, the measured pressure of a gas is No idea.the only thing is that the situation is not favorable for gas

• less than the calculated pressure, because intermolecular forces reduce the avg. force of the collisions with a unit area of the container.
• Less than the calculated pressure, because the avg. size of the gas molecules increase
• Less than the calculated pressure, because the avg. molecular speed increase.
• Greater than the calculated pressure, because the avg. molecular speed increase.
• Greater than the calculated pressure, because intermolecular forces increase the frequency of the collisions with a unit area of the container.

22. a 0.10 gram sample of gas occupies 110mL at 100 C and 0.9 atm. What is the molecular weight?
(just set up the calculation) PMW=DRT

Guys I thought we do the following calculation:

PV=nRT for n we can right mass/molecular weight so

PV=(mass/molecular weight) RT and here we just substitute P and V for MW so we get

MW = (mass)(R)(T)/PV which would be MW= (0.10)(0.0821)(373)/(0.9)(.110) is this right?

23. a substance is nonconducting in both the solid and liquid phases. It is hard at room temp but becomes soft enough when heated to be molded into various shapes. It is not water soluble. This substance would be characterized best by which of the following?
If you had semimetals, I would choose that!

• ionic
• metallic
• catalytic
• isotopic
• polymeric

my answer is E. what do you say?

24. two hundred grams of a hydrogen halid is added to a liter of water. If the boiling point of the solution is 102.5 C, what is the identity of the halide? Kb=0.51c/m

• fluoride (F=19.1,H=1) and wwe have 40.8 as of our MW
  
• chloride
• bromide
• iodide
• astatide

25. one mole of helium at STp is heated to 273 C. if the pressure doubles as a result, find the volume occupied by the heated gas.

• 5.6L
• 11.2L
• 22.4L
• 67.2L
• 89.6L

My answer is B. what do you say?

26. which of the following reagents would increase the solubility of calcium fluoride?

• HF
• HCl Would go with your choice since it is the only one which doesn't have common ion affect.
  
• CaCl2
• NaF
• CH3CH2OH

My answer is B. what is yours?

27. Which of the following properties increases with atomic number in group 15?

• oxidation state (if it gain proton means it has lost electron and so oxidized I think.BTW group 15 in N for mstoothy)
  
• ionization energy
• electronegativity
• electron affinity
• atomic radius

my ans. is c. but I am not sure!

...

 

[osimsDDS]

Why did you guys put Hydrolysis for formation of peptide bonds....isnt it condensation cause your losing a water molecule to form a peptide chain...hydrolysis is the break down of the peptide chain....when water is reacted and therefore it breaks the bonds

 

[Glycogen]

Agree with osmos on last Q atomic radii is right.Dumb mistake!!!!!

 

[Dencology]

hey, how did you get 22.4. if pressure doubles, does not the volume become 1/2. can you explain this please. thank.

 

[Glycogen]

hey, how did you get 22.4. if pressure doubles, does not the volume become 1/2. can you explain this please. thank.

At STP so:

(22.4)(1)/273=(V)(2)/546 --> (22.4)(1)(546)/(2)(273)=V2=22.4

 

[Glycogen]

Your pressure got double and also tem and so volume doesnot change.

 

[osimsDDS]

hey, how did you get 22.4. if pressure doubles, does not the volume become 1/2. can you explain this please. thank.

yes your right the volume is halfed but then they say the temperature is doubled so then volume is doubled from half to 1....so it goes from 22.4 to 11.2 when you double the pressure and then it goes again to 22.4 when you double the temp...

 

[Glycogen]

Why did you guys put Hydrolysis for formation of peptide bonds....isnt it condensation cause your losing a water molecule to form a peptide chain...hydrolysis is the break down of the peptide chain....when water is reacted and therefore it breaks the bonds

Osims,I'm working on it.Wiki it to see what is the right answer,my reasoning was that when you are forming a peptide bond you are losing water.But,I might be completely wrong.Let me find out or if you can elaborate your reasoning would be great.Thanks

 

[osimsDDS]

Osims,I'm working on it.Wiki it to see what is the right answer,my reasoning was that when you are forming a peptide bond you are losing water.But,I might be completely wrong.Let me find out or if you can elaborate your reasoning would be great.Thanks

look no further...here it is in the first sentence...

http://en.wikipedia.org/wiki/Peptide_bonds

 

[Glycogen]

look no further...here it is in the first sentence...

http://en.wikipedia.org/wiki/Peptide_bonds

Great.Thank you.I was thinking about dehydration.It is a good Q.

 

[Dencology]

osims, where does it say that the temp doubles up? if we use PV=nRT then doubling the pressure 1/2 the volume, just like you said. but then i just don't understand where you came up with doubling the temp.

guys, what about the other question, anyone found any answer to it?

 

[Mstoothlady2012]

osims, where does it say that the temp doubles up? if we use PV=nRT then doubling the pressure 1/2 the volume, just like you said. but then i just don't understand where you came up with doubling the temp.

guys, what about the other question, anyone found any answer to it?

At STP T = 273 K. In this question the given T = 273 C = 273 + 273 = 546 = which is twice the STP

 

[Mstoothlady2012]

Duh!! I was thinking the same way as glycogen, that's why I chose hydrolysis. Thanks osims!

 

[osimsDDS]

osims, where does it say that the temp doubles up? if we use PV=nRT then doubling the pressure 1/2 the volume, just like you said. but then i just don't understand where you came up with doubling the temp.

guys, what about the other question, anyone found any answer to it?

25. one mole of helium at STp is heated to 273 C. if the pressure doubles as a result, find the volume occupied by the heated gas.

In the question is tells you it was first at STP (temp=273K at stp and pressure=1atm) and then it was heated to 273C...which is what: 273+273= 546) thats doubling the temperature right...so it would cancel out the affect of the pressure being doubled...

 

[flycd05]

Your pressure got double and also tem and so
volume doesnot change.

it says that the pressure is doubled. but how do u know that the temp is also doubled?? i'm missing this - it says that the gas is heated (so obvi is its gonna be more than 273 K) but how do u know its doubled and why?

 

[osimsDDS]

it says that the pressure is doubled. but how do u know that the temp is also doubled?? i'm missing this - it says that the gas is heated (so obvi is its gonna be more than 273 K) but how do u know its doubled and why?

you guys are missing the big picture...it says its first at STP then heated to 273C....

STP=273K
After it is heated to 273C= 273C convert to Kelvin so you add 273 right...which is 546K

Now whats the difference between 546k and 273K...doubling the temperature...

 

[Dencology]

uhhan. thanks.

 

[osimsDDS]

hey dencology can you post the answer please, thanks

 

[hannah999]

doesnt functional unit mean the smallest part?

 

[nixon13]

14. which of the following do plant cells possess that animal cells do not?

a.vacuoles
b.cell membranes
c.chloroplasts
d.roots
e.mitochondria

15. Which of the following best describes the enzymes that catalyzes the conversion of glucose into glucosephosphate?

• carbohydrate
• lipid
• polypeptide chain ?
• nucleic acid
• amino acid

16. which type of transport across the cell memebrne does not utilize a carrier molecule?

• simple diffusion
• somosis
• receptor-mediated endocytosis
• active transport

17. which of the following statements best describes a difference between the endocrine and nervous system?

• the nervous system is involved in homeostasis while the endocrine system is not.
• products of the endocrine system travel in the blood while nervous signals travel though neurons.
• Nerves produce hormones and endocrine glands produce nerotransmitters.
• Tissues in the endocrine system are myelinated while those in the nervous system are not.
• The endocrine system uses chemicals, and the nervous system does not.

18. what type of reaction in involved in the assembly of peptiede bond?

• condensation rxn
• hydrolysis rxn
• catabolic rxn
• fermentation rxn
• metabolic rxn

19. genetic recombination during meiosis results from

• synapsis
• crossing over
• linkage

20. the functional unit of vertebrate skeletal muscle consists of

• one muscle fiber and the motor end plate.
• An entire muscle
• A single motor neuron and the group of muscle cells innervated by its anon.
• All of the muscle fibers linked by a spinal nerves
• A group of myofibrils and their myofilaments ?

21. at low temp and high pressures, the measured pressure of a gas is

• less than the calculated pressure, because intermolecular forces reduce the avg. force of the collisions with a unit area of the container. ?
• Less than the calculated pressure, because the avg. size of the gas molecules increase
• Less than the calculated pressure, because the avg. molecular speed increase.
• Greater than the calculated pressure, because the avg. molecular speed increase.
• Greater than the calculated pressure, because intermolecular forces increase the frequency of the collisions with a unit area of the container.

22. a 0.10 gram sample of gas occupies 110mL at 100 C and 0.9 atm. What is the molecular weight?
(just set up the calculation)

pv=nRT so (.9)(.110)=n(.0821)(373) n= .00323mol so .10g/.00323mol= 30.93g/mol


Guys I thought we do the following calculation:

PV=nRT for n we can right mass/molecular weight so

PV=(mass/molecular weight) RT and here we just substitute P and V for MW so we get

MW = (mass)(R)(T)/PV which would be MW= (0.10)(0.0821)(373)/(0.9)(.110) is this right?

23. a substance is nonconducting in both the solid and liquid phases. It is hard at room temp but becomes soft enough when heated to be molded into various shapes. It is not water soluble. This substance would be characterized best by which of the following?

• ionic
• metallic
• catalytic
• isotopic
• polymeric ?

my answer is E. what do you say?

24. two hundred grams of a hydrogen halid is added to a liter of water. If the boiling point of the solution is 102.5 C, what is the identity of the halide? Kb=0.51c/m

• fluoride
• chloride
• bromide
• iodide
• astatide

IDK

25. one mole of helium at STp is heated to 273 C. if the pressure doubles as a result, find the volume occupied by the heated gas.

at STP 22.4 L of a gas is occupied. so p1v1/t1= p2v2/t2

so (1)(22.4)/273= (2)(v2)/546 v2=22.4L

• 5.6L
• 11.2L
• 22.4L
• 67.2L
• 89.6L

My answer is B. what do you say?

26. which of the following reagents would increase the solubility of calcium fluoride?

Its none of them with F or Ca because of common ion effect which decreases solubility. I choose HCl.

• HF
• HCl
• CaCl2
• NaF
• CH3CH2OH

My answer is B. what is yours?

27. Which of the following properties increases with atomic number in group 15?

atomic radius because atomic number increases as you go down the group. Atomic radius is the only one that increases as you go down a group.

• oxidation state
• ionization energy
• electronegativity
• electron affinity
• atomic radius

my ans. is c. but I am not sure!

28. a 147 gram sample of K2Cr2 O7 (294.2g/mol) contains:

• 2 mole of potassium
• 104.0gram of chromium
• 2.5 mole of oxygen
• 1 mole of molecules
• 5.5 mole of atoms

Im not sure. too lazy to try stuff.

 

[Dencology]

Ok. here are the answer. but i don't have the answers to some of these questions so if you guys can help, it would be great. Osims, you did a great job explaining.


14. which of the following do plant cells possess that animal cells do not?

a.vacuoles
b.cell membranes
c.chloroplasts
d.roots
e.mitochondria

15. Which of the following best describes the enzymes that catalyzes the conversion of glucose into glucosephosphate?

• carbohydrate
• lipid
• polypeptide chain
• nucleic acid
• amino acid

16. which type of transport across the cell memebrne does not utilize a carrier molecule?

• simple diffusion
• somosis
• receptor-mediated endocytosis
• active transport

17. which of the following statements best describes a difference between the endocrine and nervous system?

• the nervous system is involved in homeostasis while the endocrine system is not.
• products of the endocrine system travel in the blood while nervous signals travel though neurons.
• Nerves produce hormones and endocrine glands produce nerotransmitters.
• Tissues in the endocrine system are myelinated while those in the nervous system are not.
• The endocrine system uses chemicals, and the nervous system does not.

18. what type of reaction in involved in the assembly of peptiede bond?

• condensation rxn
• hydrolysis rxn
• catabolic rxn
• fermentation rxn
• metabolic rxn

19. genetic recombination during meiosis results from

• synapsis
• crossing over
• linkage

20. the functional unit of vertebrate skeletal muscle consists of

• one muscle fiber and the motor end plate.
• An entire muscle
• A single motor neuron and the group of muscle cells innervated by its axon.
• All of the muscle fibers linked by a spinal nerves
• A group of myofibrils and their myofilaments

21. at low temp and high pressures, the measured pressure of a gas is

• less than the calculated pressure, because intermolecular forces reduce the avg. force of the collisions with a unit area of the container.
• Less than the calculated pressure, because the avg. size of the gas molecules increase
• Less than the calculated pressure, because the avg. molecular speed increase.
• Greater than the calculated pressure, because the avg. molecular speed increase.
• Greater than the calculated pressure, because intermolecular forces increase the frequency of the collisions with a unit area of the container.

22. a 0.10 gram sample of gas occupies 110mL at 100 C and 0.9 atm. What is the molecular weight?
(just set up the calculation)

Guys I thought we do the following calculation:

PV=nRT for n we can right mass/molecular weight so

PV=(mass/molecular weight) RT and here we just substitute P and V for MW so we get

MW = (mass)(R)(T)/PV which would be MW= (0.10)(0.0821)(373)/(0.9)(.110) is this right?

23. a substance is nonconducting in both the solid and liquid phases. It is hard at room temp but becomes soft enough when heated to be molded into various shapes. It is not water soluble. This substance would be characterized best by which of the following?

• ionic
• metallic
• catalytic
• isotopic
• polymeric

24. two hundred grams of a hydrogen halid is added to a liter of water. If the boiling point of the solution is 102.5 C, what is the identity of the halide? Kb=0.51c/m

• fluoride
• chloride
• bromide
• iodide
• astatide

25. one mole of helium at STp is heated to 273 C. if the pressure doubles as a result, find the volume occupied by the heated gas.

• 5.6L
• 11.2L
• 22.4L
• 67.2L
• 89.6L

My answer is B. what do you say?

26. which of the following reagents would increase the solubility of calcium fluoride?

• HF
• HCl
• CaCl2
• NaF
• CH3CH2OH

27. Which of the following properties increases with atomic number in group 15?

• oxidation state
• ionization energy
• electronegativity
• electron affinity
  
• atomic radius

28. a 147 gram sample of K2Cr2 O7 (294.2g/mol) contains:

• 2 mole of potassium
• 104.0gram of chromium
• 2.5 mole of oxygen
• 1 mole of molecules
• 5.5 mole of atoms

I am not sure about this one.

 

[osimsDDS]

28. a 147 gram sample of K2Cr2 O7 (294.2g/mol) contains:

2 mole of potassium
104.0gram of chromium
2.5 mole of oxygen
1 mole of molecules
5.5 mole of atoms

For this last one, if you take the 147gx(mole/294.2g) you get .5 moles of the molecule...so the amount of moles of oxygen has to be 7/2=3.5moles so cant be that one

It isnt 2 moles of potassium cuz we calculated it to be half a mole of the whole molecule so K would have 1 mole not 2...

we would only have 1 mole of chromium which is 52 grams...

It has to be 5.5 moles of atoms because if you divide K2Cr2O7 by 2 (because we found that the molecule only contains half the mole not the full mole) it would be KCrO3.5 when you add up all of those atoms and their respective moles...you will get K1Cr1O3.5, so its 1+1+3.5=5.5 moles of atoms...

 

[flycd05]

thanks for the explanation for #25!

btw, why isnt #16's answer osmosis and not simple diffusion???

 

[osimsDDS]

thanks for the explanation for #25!

btw, why isnt #16's answer osmosis and not simple diffusion???

cuz simple or passive diffusion could be either passive diffusion without a carrier protein: this is usually when small polar substances like H20, CO2 cross the membrane and also nonpolar small substances like O2. When you have larger molecules that are polar you have to use a protein carrier...this is facillitated diffusion...

you prob already know this....But overall here it is:

Simple Diffusion:
-passive
-facilitated

Active Transport/Diffusion:
-Proton pump (like Na+/K+ proton pump)
-needs energy

Osmosis:
-only thing is water movement which is simple diffusion of a small polar molecule through membranes...

So basically osmosis is simple diffusion but without a protein carrier so its the answer...haha that was long but hopefully you understand the reasoning behind choosing that answer...

 

[flycd05]

cuz simple or passive diffusion could be either passive diffusion without a carrier protein: this is usually when small polar substances like H20, CO2 cross the membrane and also nonpolar small substances like O2. When you have larger molecules that are polar you have to use a protein carrier...this is facillitated diffusion...

you prob already know this....But overall here it is:

Simple Diffusion:
-passive
-facilitated

Active Transport/Diffusion:
-Proton pump (like Na+/K+ proton pump)
-needs energy

Osmosis:
-only thing is water movement which is simple diffusion of a small polar molecule through membranes...

So basically osmosis is simple diffusion but without a protein carrier so its the answer...haha that was long but hopefully you understand the reasoning behind choosing that answer...

ok got it! thanks for the explanation