Quarter 1 Midterm Review

1. The percent by mass of oxygen in Na2SO4

(formula mass = 142) is closest to

1) 11%

3) 45%

2) 22%

4) 64%

2. Given the unbalanced equation:

__Al(s) + __O2(g) → __Al2O3(s)

3.

4.

5.

6.

7.

balance the equation using smallest whole number coefficients.

The percent by mass of aluminum in Al2O3 is approximately 1) 18.9

3) 47.1

2) 35.4

4) 52.9

What is the approximate percent composition by mass of CaBr2 (formula mass = 200)?

1) 20% calcium and 80% bromine

2) 25% calcium and 75% bromine

3) 30% calcium and 70% bromine

4) 35% calcium and 65% bromine

What is the empirical formula for C3H6?

1) CH

2) CH2

3) CH3

4) CH6

Which represents both an empirical and a molecular formula?

1) P2O5

2) N2O4

3) C3H6

4) C6H12O6

The number of atoms in 2 grams of calcium is equal to

1) 2 × 6.02 × 1023

40

2) 40 × 6.02 × 1023

2

3) 6.02 × 1023

2 × 40

4) 2 × 40 × 6.02 × 1023

8. At STP, 32 grams of O2 would occupy the same volume as

1) 64 g of H2

2) 32 g of SO2

3) 8.0 g of CH4

4) 4.0 g of He

9. Which compound has the empirical formula CH2

O?

1) CH3OH

2) CH3CH2OH

3) HCOOH

4) CH3COOH

10. Which list consists of types of chemical formulas? 1) atoms, ions, molecules

2) metals, nonmetals, metalloids

3) empirical, molecular, structural

4) synthesis, decomposition, neutralization

11. What is the total number of neon atoms contained in 20.2 grams of neon gas?

3) 3.01 × 1023

1) 1.01 × 1024

2) 2.02 × 1024

4) 6.02 × 1023

12. Given the balanced equation:

X + Cl2 - C2H5Cl + HCl

Which molecule is represented by X?

1) C2H4

2) C2H6

3) C3H6

4) C3H8

13. Which equation is correctly balanced?

3) 2 H2 + O2 → 2 H2O

1) H2 + O2 → H2O

2) Ca + Cl2 → CaCl

4) Ca + C12 → Ca2Cl

14. Given the unbalanced equation:

__Al2(SO4)3 + __Ca(OH)2 → __Al(OH)3 +

__CaSO4

Balance the equation using smallest whole number coefficients.

Quarter 1 Midterm Review

15. At STP, 25.0 liters of a gas