The Mole: Conversions, Mass Determination, and Hydrates

The molar mass of carbon dioxide (CO2) is _____.44.0 g/mol47.0 g/mol 43.0 g/mol 42.5 g/mol

44.0 g/mol

A mole is a unit of measure, describing the amount of a chemical substance that contains as many atoms, molecules, or formula units as there are in exactly 12 grams of pure oxygen.true/false

false

The first step when converting between mass of a compound and moles of a compound is to determine the molar mass of the compound.True/False

True

Water is released from a hydrate by _____.

heating the hydrate

There are _____ atoms in 12 grams of pure carbon (12C).12.022 x 10236.022 x 10234.023 x 1023 1.00 x 1023

6.022 x 1023

One mole of a compound has the mass that is equal to the molecular mass.True/False

True

The element oxygen has a molar mass of 15.999 grams, thus one mole of oxygen is equal to _____ g/mol.31.99815.999 x 1023 15.99931.998 x 1023

15.999

A hydrate is a compound in which water molecules are a part of the crystalline structure.True/False

True

When copper sulfate heptahydrate is heated, how many moles of water are available to be released?14 7 9

7

The second step in converting between the mass of a compound and moles of a compound is to use the molar mass to convert grams to moles.True/False

True

Calculate the moles of anhydrous CuSO4 present in a sample with 0.5 g CuSO4 at a molar mass of 159.61 g/mol.

0.00313

Based on the correct answer to question 7, calculate the ratio of moles of H2O to moles of anhydrous CuSO4 if there were 0.085 mols of released H2O.

27

After heating a sample of hydrated CuSO4, the mass of released H2O was found to be 2.0 g. How many moles of H2O were released if the molar mass of H2O is 18.016 g/mol?

0.111

Based on the correct answer to question 8, what is the empirical formula for hydrated CuSO4?

CuSO4‚óŹ27H2O

Cu (II) sulfate exists as a hydrate. It has many practical uses including use as a fungicide and pesticide. When mixed with chromium and arsenic it forms the wood preservative called CCA. CCA was used in pressure treated wood to protect wood from rotting due to insects and microbial agents. Because CCA treated wood contains toxic heavy metals, its use has been discontinued for home use and children's play sets.1. A chemist is given a sample of the CuSO4 hydrate and asked to determine the empirical formula of it. The original sample weighed 42.75 g. After heating to remove the waters of hydration, the sample weighed 27.38 g. Determine the formula for this hydrate.

CuSO4.5H2O