Adv CHEM Fall Mid-Term Unit 1

What is the answer with the proper significant figures for the following equation?
(7.6 + 8.401) × 4.2 × 0.688 = 

• 46.237 
• 46.24 
• 46 
• 46.2

How may significant digits are found in 765.000? 

• 3
• 4
• 5
• 6

You have a reported 1,000.g bar of gold, but every time you place it on the balance to determine its mass, the balance reports that the bar has a mass of 937g.  This is an example of:

• accuracy
• precision
• BOTH accuracy and precision
• NEITHER accuracy nor precision

A piece of metal has a volume of 0.250 hogs heads and a mass of 54.242 kg. Calculate the density of the metal in pennyweights per peck.
1 pennyweight (pw) = 1.55 grams
1 hogs head (hh) = 238.5 liters
1 peck = 9.091 liters

• I
• II
• III
• IV

The number 2 × 10¹⁵ is

• greater than one. 
• smaller than 2.0 × 10⁻¹⁵. 
• less than one. 
• More information is needed. 

A sample of metal beads was measured to have a mass of 425g. The beads were placed in a graduated cylinder that initially had 100.mL of water.  After placing the beads in the graduated cylinder the water level rose to 148mL.  Given the following densities, select the most likely identity of the metal.

• Gold
  19.3g/mL
• Copper
  8.86g/mL
• Bronze
  9.87g/mL
• Lead
  11.37g/mL

Which of the following is a physical change? 

• Light is given off as two liquids mix.
  
• An iron nail rusts.
  
• A liquid evaporates. 
• Carbon dioxide is produced by burning gasoline. 

Which of the following is an extensive physical property? 

• density 
• mass 
• reactivity 
• color 

What is NOT true of a gas? 

• A gas exerts pressure continuously and in all directions on the walls of a vessel in which it is contained. 
• The particles of a gas tend to perme- ate the entire volume into which they are released. 
• The particles of a gas are held together by strong attractive forces. 
• A gas can be compressed into a very small volume. 

Which statement is NOT true for a sample of a compound? 

• Each of the elements in the substance occurs in a constant proportion no matter what sample is tested. 
• The sample melts at a specific temperature. 
• The sample contains only one type of substance and cannot be separated into other components without causing a chemical change. 
• The sample can be separated using the physical properties of ingredients that make up the sample.