chemistry chapter 1 & 2

94.20 g / 3.16722 mL =

29.7 g/mL

400. mm

3

3.17497 mol to three significant figures

3.18 mol

0.004590 kg

4

0.4004 mL

4

1.0030 km

5

6000.0 g

5

The element fluorine, an explosively reactive non-metal, has an atomic diameter of 50 picometers. How many fluorine atoms would need to be lined up next to each other to achieve a length of 5 centimeters?

5 cm x 1 x 1010pm/1cm = 5 x 1010 pm Since 5 cm = 5 x 1010 pm, and each atom has a diameter of 50 (5 x 101) pm, then 5 x 1010 pm/5 x 101 pm/atom = a total of 1 x 109 or one billion fluorine atoms would be required.

52.8005 mg to five significant figures

52.801 mg

How many mL are there in 0.603 L?

6.03 x 10-1 L x 1 x 103 mL =1 L 6.03 x 102 mL

6.078 g + 0.3329 g =

6.411 g

What is the mass of a sample of material that has a volume of 55.1 cm3 and a density of 6.72 g/cm3? (Hint: use density formula)

6.72 g/cm3 = mass/55.1 cm3 Mass = 370. g

67.029 g to three significant figures

67.0 g

How many grams are there in 882 μg?

8.82 x 10-4 g

What is the percent error of a length measurement of 0.229 cm if the correct value is 0.225 cm?

(0.225 cm - 0.229 cm)/0.225 cm x 100% = -1.78%

A handbook gives the density of calcium as 1.54 g/cm3. What is the percent error of a density calculation of 1.25 g/cm3 based on lab measurements?

(1.54 g/cm3 - 1.25 g/cm3)/1.54 g/cm3 x 100% = 18.8%

A student measures the mass of a sample as 9.67 g. Calculate the percent error if the correct mass is 9.82 g.

(9.82 g - 9.67 g)/9.82 g x 100% = 1.53%

0.15 L to one significant figure

0.2 L

A sample of a substance that has a density of 0.824 g/mL has a mass of 0.451 g. What is the volume of this substance? (Hint: use density formula)

0.824 g/mL = 0.451 g/volume Volume = 0.547 mL

6000 g

1

8.2 cm - 7.11 cm =

1.1 cm

0.8102 m x 3.44 m =

2.79 m2

Why is it important for a measurement system to have an international standard

Standards help avoid confusion and ambiguity when taking measurements. A meter will always be the same length, no matter who is taking the measurement or where it is being taken.

define: physical property and give an example

a characteristic that can be observed or measured without changing the identity of a substance. Examples: boiling and melting points.

what is the difference between intensive and extensive properties?

Extensive properties depend on the amount of matter present, while intensive properties remain the same no matter how much matter is present. Extensive properties include volume and mass, while intensive properties include boiling point and density.

What is the SI derived unit for density?

Grams per cubic centimeter (solid) or grams per milliliter (liquid)

What is the volume, in cubic meters, of a rectangular solid that is 0.25 m long, 6.1 m wide, and 4.9 m high

Volume = 0.25 m x 6.1 m x 4.9 m = 7.5 m3

define: physical change and give an example

a change in a substance that does not involve a change in the identity of the substance. Examples: changes of state (solid, liquid, gas), changes in appearance.

define: chemical change and give an example

a change in which one or more substances are converted into different substances. Examples: burning, all chemical reactions, most color changes.

how is energy involved in changes in matter? name some possible forms

As energy increases, substances change from lower-energy states (solid) to higher-energy states (liquid and gas). Particles increase in velocity and move farther away from each other. Energy can be cause these changes in the form of heat, light, or other electromagnetic radiation (ultraviolet, microwave, etc).

how is a liquid similar to a gas?

Both have higher particle energy than a solid, and neither have a definite shape.

Find the density of a material, given that a 5.03 g sample occupies 3.24 mL.

Density = 5.03 g/3.24 mL = 1.55 g/mL

how is a pure substance different from a mixture?

Pure substances have a fixed composition, every molecule has same properties. Include compounds or elements. Pure substances can only be broken down through chemical means (electrolysis, reaction, combustion). Mixtures are a blend of two or more kinds of matter, each of which retains its own identity and properties. Composition may vary. Mixtures can be separated by physical means (filtration, evaporation). They can be homogeneous or heterogeneous.

What is the general form for writing numbers in scientific notation?

There can only be one digit to the left of the decimal place

State the rules for finding number of significant figures when doing addition and subtraction

answer should have the same number of decimal places as the number in the original equation with the least number of decimal places.

State the rules for finding number of significant figures when doing multilication and division

answer should have the same number of significant figures as the number in the original equation with the least number of significant figures.

chemical or physical change? Milk turns sour.

chemical

What is the law of conservation of energy?

energy can neither be created nor destroyed in a chemical reaction or physical change

liquid vs. gas

gas has higher energy; particles are not touching. No definite shape or volume in gas.

define: chemical property and give an example

involves ability to undergo changes that transform one substance into a different substance. Examples: ability to burn, ability to rust, reactivity.

solid vs. liquid

liquid has higher energy, particles can move past each other whereas solid particles vibrate in place and have lower energy.

What is the law of conservation of mass?

mass can neither be created nor destroyed in a chemical reaction or physical change.

chemical or physical change? A piece of wood is sawed in half.

physical

chemical or physical change? Melted butter solidifies in the refrigerator

physical

What is the SI derived unit for area?

square meters

define: volume

the amt of space occupied by an object

define: mass

the measure of the amt of matter