GEN CHEM question form ACE THE DAT

[queencrown]

Advertisement - Members don't see this ad

HI..can someone solve this step by step?? I can't get the exact correct answer! I get a number close to the answer but not the exactly...thanks!

A solution is prepared by dissolving 25.0 g of ZnSO4 in 100.0g. of H2O. This solution has a density of 1.124 g/mL. Calculate the molarity of this solution

I suck at gen chem 🙁!

 

[queencrown]

ahh the answer is 1.39 M

 

[PooyaH]

Yeah check your PM 😀

 

[Tina324]

yup me too..i got 1.35...what am i doing wrong? i solved for the volume a got .111L and just put moles of solute over L of solution (.15/.111)

thankss =)

 

[nzaads]

how do you find the volume?😕

 

[Optimism Smiles]

yup me too..i got 1.35...what am i doing wrong? i solved for the volume a got .111L and just put moles of solute over L of solution (.15/.111)

thankss =)

That is right...it is just the rounding that throws it off a wee bit. Don't panic!

 

[Optimism Smiles]

how do you find the volume?😕

You find the volume using density. Density = mass/volume. Since we know the mass of the solution (add the mass of water and solute to find total mass), we can rearrange the density formula to get V = mass/density. So V = (100g + 25g)/1.124 g/mL = 111.21 mL. (Make sure you convert it to Liters before figuring out the rest of the problem because it asks for MOLARITY! 🙂 )

 

[Tina324]

thanks optimism!