10.3 Review: % Comp, Empirical and Molecular Formulas

What is the general formula for percent composition?

• $\%\ comp\ =\ \frac{\left(mass\ of\ element\right)}{\left(mass\ of\ compound\right)}$

• $\%\ comp\ =\ \frac{\left(molar\ mass\right)}{\left(mass\ of\ compound\right)}$

• $\%\ comp\ =\ \frac{\left(mass\ of\ element\right)}{\left(molar\ mass\ of\ element\right)}$

What formula do you use to get the ratio between molecular and empirical formula when calculation molecular formula?

• $\frac{\left(empirical\ formula\ mass\right)}{\left(molecular\ formula\ mass\right)}$

• $\frac{\left(mass\ of\ element\right)}{\left(mass\ of\ compound\right)}$

• $\frac{\left(molecular\ formula\ mass\right)}{\left(empirical\ formula\ mass\right)}$

• $\frac{\left(mass\ of\ compound\right)}{\left(mass\ of\ element\right)}$

A 130 g of sulfur dioxide is decomposed and 64 g of sulfur is collected. WHat is the percent composition of this compound?

• 49.2% SO2

• 49.2%S, 50.8% O

• 50.8% S, 49.2% O

• 49.2% S, 50.8% O2

Tags

NGSS.HS-PS1-7

What is the percent composition of a compound made of 46 g Na and 70 g Cl?

• 39.7%NaCl

• 60.3% Na, 39.7% Cl

• 39.7% Na, 60.3% Cl

• 39.7% Na2, 60.3% Cl2

What is the percent composition of N2O3?

• 36.8% N, 63.2% O

• 63.2% N. 36.8% O

• 18.4% N, 21.1% O

• 21.1% N, 18.4% O

What is the percent composition of NaSO4?

• 53.8% Na, 19.3% S, 26.9% O

• 26.9% Na, 53.8% S, 19.3% O

• 26.9% Na, 19.3% S, 53.8% O

• 19.3% Na, 26.9% S, 53.8% O

Tags

NGSS.HS-PS1-7

What is the mass of N in 75 g of N2O3

• 27.6 g

• 28.0 g

• 28.0 g/mol

• 47.4 g

Tags

NGSS.HS-PS1-7

What is the mass of O in 23 g of N2O3?

• 14.5 g

• 15.3 g

• 48 g

• 48g/mol

Tags

NGSS.HS-PS1-7

What is the empirical formula of C4H8?

• C4H8

• C2H4

• CH2

• CH

Which molecular formula matches this empirical formula, CH?

• C4H8

• C4H6

• C4H4

• C4H2