Chapter 3 & Acids

Mass of Compounds and moles

100

What is the difference between formula mass and molecular mass?

Formula Mass is for ions. Molecular Mass is for covalent molecules.

200

Without your periodic table determine the mass of Methan, CH₄, in amu.

12C + 4H -> 16amu.

300

If the mass of Fermium is 257 amu, what is its mass in grams per mole?

257 g/mol.

400

How many moles of Oxygen, O, are there in 3 moles of N₂O₄?

12 moles O

500

How many atoms of Hydrogen, H, are there in 0.25 moles of ethanol, C₂H₅OH?

9.033*10²³ atoms of Hydrogen.

Empirical and Molecular Formulas

100

What is the empirical formula of C₂H₄?

CH₂

200

1.71423 grams of Carbon and 4.571423 of Oxygen are found in an unknown sample. What is the sample's Empirical Formula?

CO₂

300

The Empirical Formula of a compound is CH₂O. The compound has a molecular mass of 180g/mol. What is its molecular formula?

C₄H₈O₄

400

Either gain 100 points or remove 200 points from one other team.

Hi.

500

A sample compound has 15.8865 grams of Copper, 7 grams of Nitrogen, and 24 grams of Oxygen. The molar mass of this compound is 187.456 g/mol. What is its molecular formula?

Cu(NO₃)₂

Percent Composition by Mass

100

1 mole of carbonate has 12 grams of Carbon and 48 grams of Oxygen. What are the percents by mass of each of those elements?

Carbon: 20%

Oxygen: 80%

200

Does Nitrate or Nitrite have a higher percentage by mass of Oxygen?

Nitrate

300

Deoxyadenosine Monophosphate has the chemical formula C₁₀H₁₄N₅O₆P. What is the parent by mass of Carbon?

36.25%

400

What are the percents by mass of Sulur and Oxygen in Sulfate?

Sulfur: 33%

Oxygen: 67%

500

What is the percentage by mass of Phosphorous in 5 moles of Ammonium Phosphate?

20.81%

Concentration

100

What are the two units used to compute molarity?

moles/Liters

200

5 mols of NaCl are dissolved in 500 mL of water. What is the molarity of the solution?

10M

300

Order from solution, solute, and solvent from smallest to largest mass.

solute, solvent, solution

400

10 grams of MgCl is dissolved in 350cm³ of water. What is its molarity?

0.29996M

500

A solution with a volume of 2L is 20% HF by mass. The density of the solution is 1.5 g/mL. If the solution is diluted with water to 5L what is the mass of HF in the solution?

600 grams.

Acids

100

What cation is part of every acid?

H⁺ which is a proton.

200

Are all acids aqueous?

Yes

300

What is the name of H₂S_(aq)?

Hydrosulfuric acid

400

What are the names of HNO_3(aq) and HNO_2(aq) respectively?

Nitric Acid and Nitrous Acid

500

What is the chemical formula of sulfurous acid?

H₂SO₃