CHEM 1010 Quiz 1

Which of the following is a physical change?

Condensation forming on a window

A pure substance that cannot be broken down into simpler substances by chemical changes is a/an

Element

A Class-A 10 mL pipette is supposed to dispense 10.00 mL of water. A lab technician makes three measurements of the volume that the pipette actually dispenses, and obtains volumes of 9.70 mL, 9.69 mL, and 9.71 mL. The pipette is

Precise, but not accurate

A liquid

Takes shape of a container and forms a horizontal upper surface

The density of platinum is 21.45 g/cm3. What is the volume in cm3 of 1.27 pounds of platinum?

26.8 cm3

How many milligrams are in 405 kg?

4.05 x 108 mg

A Class-A 10 mL pipette is supposed to dispense 10.00 mL of water. A lab technician makes three measurements of the volume that the pipette actually dispenses, and obtains volumes of 10.21 mL, 9.73 mL, and 10.14 mL. The pipette is

Neither accurate or precise

What is the answer to 6.572 x 0.149 ÷ 1.7, reported to the correct number of significant figures?

0.58

How many microseconds are in 12.3 ms?

1.23 x 104 µs

What is the answer to 117.3 + 4.291 - 0.09, reported with the correct number of significant figures?

121.5

A solid

Has fixed shape and volume

A tentative explanation of observations is a/an

Hypothesis

When adding or subtracting measurements

The number of decimal places in the answer will equal the fewest decimal places in a number in the calculation

When multiplying or dividing measurements

The number of significant figures in the answer will equal the fewest significant figures in a number in the calculation

A comprehensive, testable explanation that explains a large body of experimental data is a/an

theory