Quiz 1-2

How many moles of N₂(g) molecules would contain exactly 4.0 moles of nitrogen atoms?

• 1.0

• 2.0

• 3.0

• 4.0

Three stable isotopes of an element occur in nature. What is the average atomic mass of this element?

• 102.5

• 105.0

• 107.5

• 315.0

What is the molar mass of C₂H₆O?

• 29 g/mol

• 34 g/mol

• 46 g/mol

• 68 g/mol

Given the reaction:

(NH₄)₂CO₃ → 2NH₃ + CO₂ + H₂O

What is the minimum amount of ammonium carbonate that reacts to produce 1.0 mole of ammonia?

• 0.25 mol

• 0.50 mol

• 17 mol

• 34 mol

The number of moles of ammonia in 51.0 g of NH₃ (MM = 17.0 g/mol) is

• 3.00 mol

• 3.40 mol

• 6.80 mol

• 867 mol

Magnesium reacts with aqueous silver nitrate to produce 2.16 g of silver metal in an experiment. What is the mass of magnesium reacted?

Mg + 2AgNO₃ → 2Ag + Mg(NO₃)₂

• 0.242

• 0.325

• 0.650

• 2.16

The number of molecules of benzene, C₆H₆ (MM = 78.0 g/mol) present in 13.0 g is

• 
• 
• 
• 

A compound was found to contain 80% carbon and 20% hydrogen by mass. What is the empirical formula of this compound?

• CH₂

• CH₃

• C₂H

• C₃H₂

The empirical formula of a compound is one where

• all of the subscripts are > 1

• only the molar ratios are given

• the subscripts of all of the elements are 1

• the atomic symbols are shown without subscripts

When the equation is balanced with small whole numbers the sum of the coefficients will be:

H₂O + Cl₂O → HOCl

• 3

• 4

• 5

• 6