HW Stioch General questions

A formula with the lowest whole # ratio of elements in a compound is called

• Molecular Formula
• Chemical Formula
• Empirical Formula 
• Distance Formula

What is the empirical formula for N₂S₃?

• NS

• N₃S₂

• N₂S₃

• N₁S_1.5

Given the following: 42.07g Na, 18.89g P, and 39.04g O, determine the empirical formula.

• NaPO2

• Na2PO3

• Na3PO4

• NaPO4

A compound consists of 72.2% magnesium(Mg) and 27.8% nitrogen(N) by mass. What is the empirical formula?

• Mg₄N₃

• MgN₂

• Mg₃N₂

• MgN

What is the molecular formula if the empirical formula is CH₂O and the molecular molar mass is 180.18?

• CH₂O

• C₂H₄O₂

• C₄H₈O₄

• C₆H₁₂O₆

What is the percent by mass of oxygen in MgO?

• 20%
• 40%
• 50%
• 60%

A 15.67 g sample of a hydrate of magnesium carbonate was heated to drive off the water. The mass was reduced to 7.58 g. What is the formula of the hydrate?

• MgCO₃ · 5H₂O
• MgCO₃ · 4H₂O
• MgCO₃ · 6H₂O
• MgCO₃ · 1H₂O

Basic aluminium diacetate – Its molecular formula is HOAl(CH₃CO₂)₂ How many total atoms are in this molecule?

• 4

• 12

• 17

• 20

What is the mass of 0.75 moles of (NH₄)₃PO₄?

• 101.75 g
• 121.75 g
• 111.75 g
• 131.75 g

Determine the amount of moles in CuBr that are in 276.9 g of the compound.

• 3.2 mol

• 1.7 mol

• 2.1 mol

• 1.9 mol