1.54 Label each of the following as either a homogeneous mixture or a heterogeneous mixture:

a. gasoline c. concrete

b. vegetable soup

d. hot coffee

1.58 Label each of the following as either a physical change or a chemical reaction:

a. A puddle of water evaporates.

b. Food is digested.

c. Wood is burned.

1.60 Label each of the following properties of sodium as either a physical property or a chemical property:

a. When exposed to air, sodium forms a white oxide.

b. The density of sodium metal at 25°C is 0.97 g/cm3.

1.62 Label each of the following as either a pure substance or a mixture:

a. sucrose (table sugar)

c. urine

b. orange juice

d. tears

1.78 Determine the temperature reading of the following thermometer to the correct number of significant figures.

1.106 If a drop of blood has a volume of 0.05 mL, how many drops of

blood is in the adult described in Question 1.105?

1.108 A newborn is 21 in in length and weighs 6 lb 9 oz. Describe the

baby in metric units.

1.122 The weather station posted that the low for the day would be −10.0°F. Convert −10.0°F to:

a. °C

b. K

1.124 Convert 300.0 K to:

a. °C

b. °F

1.128 Calculate the density of 50.0 g of an isopropyl alcohol–water mixture (commercial rubbing alcohol) that has a volume of 63.6 mL.

1.30 Why is observation a critical starting point for any scientific study?