1.4 Composition of Mixtures

Multiple Choice

A student is given two 10g samples, each a mixture of only NaCl (s) and KCl (s) but in different proportions. Which of the following pieces of information could be used to determine which mixture has the higher proportion of KCl (s)?

• The volume of each mixture

• The mass of Cl in each mixture

• The number of isotopes of Na and K

• The reaction of each mixture with water

Multiple Choice

A 5.0 g sample of MgCl₂ may contain measurable amounts of other compounds as impurities. Which of the following quantities is (are) needed to determine the sample is pure MgCl₂

• The color and density of the sample

• The mass of Mg in the sample only

• The number of moles of Cl in the sample only

• The mass of Mg and the mass of Cl in the sample

Multiple Choice

A sample of carbonate rock is a mixture of CaCO₃ and MgCO₃. The rock is analyzed in a laboratory, and the results are recorded in the table above. Which columns in the table provide all the information necessary to determine the mole ratio of Ca to Mg in the rock

• 1, 2, 5

• 2, 5, 6

• 3, 4, 6, 7

• 2, 3, 4, 5