stoichiometry problems

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1. you are required to prepare a 1 L of a .25M solution of glucose. how many grams of glucose do you need? how is the volume adjusted?
a. place 90g of glucose in an erlenmeyer flask or beaker and add 1L tap water.
b. place 45g of glucose in an erlenmeyer flask and add 1L tap water.
c. place 90g of glucose in a graduated cylinder or volumetric flask and fill with deionized water until the bottom of the menicus is on the 1L mark.
d. place 45g of glucose in a graduated cylinder or volumetric flask and fill with deionized water until the bottom of the menicus is on the 1L mark.


2. you have a concentrated stock solution of 10M NaOH and you want to use it to produce a 150mL solution of 3M NaOH. What volume of diH2O and stock solutions will you measure out to make this solution?
a. 135 mL diH2O, 15mL 10M NaOH stock
b. 45 mL diH2O, 105 mL 10M NaOH stock
c. 105 mL diH2O, 45 mL 10M NaOH stock
d. 120 mL diH2O, 30 mL 10M NaOH stock

 

[Dentite99]

1. you are required to prepare a 1 L of a .25M solution of glucose. how many grams of glucose do you need? how is the volume adjusted?
a. place 90g of glucose in an erlenmeyer flask or beaker and add 1L tap water.
b. place 45g of glucose in an erlenmeyer flask and add 1L tap water.
c. place 90g of glucose in a graduated cylinder or volumetric flask and fill with deionized water until the bottom of the menicus is on the 1L mark.
d. place 45g of glucose in a graduated cylinder or volumetric flask and fill with deionized water until the bottom of the menicus is on the 1L mark.


2. you have a concentrated stock solution of 10M NaOH and you want to use it to produce a 150mL solution of 3M NaOH. What volume of diH2O and stock solutions will you measure out to make this solution?
a. 135 mL diH2O, 15mL 10M NaOH stock
b. 45 mL diH2O, 105 mL 10M NaOH stock
c. 105 mL diH2O, 45 mL 10M NaOH stock
d. 120 mL diH2O, 30 mL 10M NaOH stock

1. .25M X 180g/mole of glucose= 45grams. I would probably choose D, because the volumes of a graduated cylinder are more precise than a flask.

2. M1V1=M2V2
(10)x=(3)(150)
x=450/10=45mL of 10M NaOH should be added to 105mL of H2O, I think it's answer C.