Grams to mol calculations

Question 1

Calculate the molecular weight of sulfuric acid

Answer 1

The molecular weight is based on the molecular formula of the compound (not the simplest)

2 hydrogens is 2x1 = 2
1 sulfur is 1x32=32
4 oxygens 4x16 = 64

98 g/mol

Question 2

Calculate the molecular weight of hexane.

• write the molecular formula
• remember the different weights of atoms
• calculate the overall

Answer 2

The molecular weight is based on the molecular formula of the compound (not the simplest)
= 6x12.0 + 14 x 1
= 72+14

= 86 amu

Question 3

write the molecular weight of carbon dioxide

Answer 3

12x1 + 14 x2
= 12+28
= 40

Question 4

what is the empirical formula for glucose?

Answer 4

CH2O

Question 5

What is the empirical formula of ribose (C5H10O5)?

Answer 5

CH2O

Question 6

Write the empirical formula for H2O2

Answer 6

HO

Question 7

Write the empirical formula for c2h6

Answer 7

ch3

Question 8

Write the empirical formula for H2O

Answer 8

H2O

Question 9

What is the avogadro constant

Answer 9

6.023x10^23

Question 10

How many grams of carbon dioxide is 0.2 moles of CO2

Answer 10

• Look up the atomic masses of carbon and oxygen. This is the number of grams per one mole of atoms.

number of grams per mole of CO2 = 12.01 + [2 x 16.00]
=12.01 + 32.00
= 44.01g/mol = molar mass

Mass = no of moles x molar mass (g/mol)

mass = 8.80 grams

Question 11

Determine the mass in grams of 3.60 mol of H2SO4.

Answer 11

2(1.008)+32.06+4(16.00) = 98.08

Mass = no of moles x molar mass (g/mol)

Question 12

Determine the mass of Nacl in one mol.

Answer 12

For NaCl, the molar mass is 58.44 g/mol. Now we can use the rearranged equation. Mass (g) = No. Moles (mol) x Molar Mass (g/mol) = 1 x 58.44. = 58.44 g.

Question 13

What is the relationship between concentration, mass and volume?

Answer 13

concentration = g/l = mass / volume

Question 14

what are the units for molarity?

Answer 14

mol/l

Question 15

what are the units for molar mass

Answer 15

g/mol