1.2 Phases and Classification of Matter

Question 1

Matter

Answer 1

Anything that occupies space and has mass, and it is all around us.

Question 2

Solid

Answer 2

Is rigid and possesses a definite shape.

Question 3

Liquid

Answer 3

Flows and takes the shape of its container, except that it forms a flat or slightly curved upper surface when acted upon by gravity. (In zero gravity, liquids assume a spherical shape.)

Question 4

Gas

Answer 4

Takes both the shape and volume of its container.

Question 5

Plasma

Answer 5

Is a gaseous state of matter that contains appreciable numbers of electrically charged particles.

Question 6

Mass

Answer 6

Is a measure of the amount of matter in an object.

Question 7

Weight

Answer 7

Refers to the force that gravity exerts on an object.

Question 8

Law of conservation of matter

Answer 8

Summarizes many scientific observations about matter: It states that there is no detectable change in the total quantity of matter present when matter converts from one type to another (a chemical change) or changes among solid, liquid, or gaseous states (a physical change).

Question 9

Pure Substance

Answer 9

Has a constant composition. All specimens of a pure substance have exactly the same makeup and properties.

Question 10

Elements

Answer 10

Pure substances that cannot be broken down into simpler substances by chemical changes.

Question 11

Compounds

Answer 11

Pure substances that are comprised of two or more elements.

Question 12

Mixture

Answer 12

Is composed of two or more types of matter that can be present in varying amounts and can be separated by physical changes, such as evaporation.

Question 13

Heterogeneous mixture

Answer 13

A mixture with a composition that varies form point to point. Example: Italian dressing, its composition can vary because it may be prepared from varying amounts of oil, vinegar, and herbs. It is not the same from point to point throughout the mixture – one drop may be mostly vinegar, whereas a different drop may be mostly oil or herbs because the oil and vinegar separate and the herbs settle.

Question 14

Homogeneous mixture

Answer 14

Also called a solution, exhibits a uniform composition and appears visually the same throughout. Sports drinks, consisting of water sugar, coloring, flavoring, and electrolytes mixed together uniformly. Each drop of a sports drink tastes the same because each drop contains the same amount of water, sugar, and other components. Note that the composition of a sports drink can vary – it could be made with somewhat more or less sugar, flavoring, or other components, and still be a sports drink.

Question 14

Molecule

Answer 14

Consists of two or more atoms joined together by strong forces called chemical bonds.

Question 15

Why is an object’s mass, rather than its weight, used to indicate the amount of matter it contains?

Answer 15

Mass is a constant property of the object and does not depend on external factors like gravity. Weight is dependent on gravity and can change based on the object’s location, making it an unreliable measure of the amount of matter in the object.

Question 16

What properties distinguish solids from liquids? Liquids from gases? Solids from gases?

Answer 16

Liquids can change their shape (flow); solids can’t. Gases can undergo large volume changes as pressure changes, liquids do not. Gases flow and change volume; solids do not.

Question 17

How does a heterogeneous mixture differ from a homogeneous mixture? How are they similar?

Answer 17

Heterogeneous mixtures are mixtures that you can see the different compounds in them, homogeneous mixtures are mixtures that have different compounds in them but are not visible. They both have different mixtures or compounds in them.

Question 18

How does a homogeneous mixture differ from a pure substance? How are they similar?

Answer 18

The mixture can have a variety of compositions; a pure substance has a definite composition. Both have the same composition from point to point.

Question 19

How does an element differ from a compound? How are they similar?

Answer 19

Element is composed of a single atom; compound is a pure substance that can be broken down into different elements. They both have atoms.

Question 20

How do molecules of elements and molecules of compounds differ? In what ways are they similar?

Answer 20

Molecules of elements contain only one type of atom; molecules of compounds contain two or more types of atoms. They are similar in that both are comprised of two or more atoms chemically bonded together.

Question 21

How does an atom differ from a molecule? In what ways are they similar?

Answer 21

An atom is the smallest unit of an element with protons, neutrons, and electrons, while a molecule is a group of two or more atoms bonded together. They are similar as building blocks of matter and participate in chemical reactions.

Question 22

Many of the items you purchase are mixtures of pure compounds. Select three of these commercial products and prepare a list of the ingredients that are pure compounds.

Answer 22

Gatorade contains water, sugar, dextrose, citric acid, salt, sodium chloride, monopotassium phosphate, and sucrose acetate Iso butyrate.

Question 23

Classify each of the following as an element, a compound, or a mixture:
(a) copper
(b) water
(c) nitrogen
(d) sulfur
(e) air
(f) sucrose
(g) a substance composed of molecules each of which contains two iodine atoms
(h) gasoline

Answer 23

(a) element; (b) compound; (c) element; (d) element; (e) mixture; (f) compound; (g) element; (h) mixture.

Question 24

Classify each of the following as an element, a compound, or a mixture:
(a) iron
(b) oxygen
(c) mercury oxide
(d) pancake syrup
(e) carbon dioxide
(f) a substance composed of molecules each of which contains one hydrogen atom and one chlorine atom
(g) baking soda
(h) baking powder

Answer 24

(a) element; (b) element; (c) compound; (d) mixture; (e) compound; (f) compound; (g) compound; (h) mixture.

Question 25

A sulfur atom and a sulfur molecule are not identical. What is the difference?

Answer 25

Sulfur atom is a single unit, a sulfur molecule is a combination of multiple sulfur atoms bonded together to form a larger structure.

Question 26

How are the molecules in oxygen gas, the molecules in hydrogen gas, and water molecules similar? How do they differ?

Answer 26

In each case, a molecule consists of two or more combined atoms. They differ in that the types of atoms change from one substance to the next.

Question 27

Why are astronauts in space said to be “weightless,” but not “massless”?

Answer 27

Astronauts in space are said to be “weightless” because they are in a state of free fall, orbiting Earth. This means they are falling towards Earth but moving forward fast enough that they keep missing it. As a result, they experience microgravity, which makes them feel weightless because there is no solid surface pushing back on them. However, they are not “massless” because mass is a measure of the amount of matter in an object, and this does not change regardless of location. The astronauts still have the same amount of matter in their bodies, so their mass remains constant.

Question 28

Prepare a list of principal chemicals consumed and produced during the operation of an automobile.

Answer 28

Gasoline (a mixture of compounds), oxygen, and to a lesser extent nitrogen are consumed. Carbon dioxide and water are the principal products. Carbon monoxide and nitrogen oxides are produced in lesser amounts.

Question 29

Matter is everywhere around us. Make a list by name of fifteen different kinds of matter that you encounter every day. Your list should include (and label at least one example of each) the following: a solid, a liquid, a gas, an element, a compound, a homogenous mixture, a heterogeneous mixture, and a pure substance.

Answer 29

1. Solid: Wood
2. Liquid: Water
3. Gas: Oxygen
4. Element: Gold
5. Compound: Salt
6. Homogeneous Mixture: Vinegar
7. Heterogeneous Mixture: Salad
8. Pure Substance: Distilled Water

Question 30

When elemental iron corrodes it combines with oxygen in the air to ultimately form red brown iron (III) oxide called rust. (a) If a shiny iron nail with an initial mass of 23.2 g is weighed after being coated in a layer of rust, would you expect the mass to have increased, decreased, or remained the same? Explain. (b) If the mass of the iron nail increases to 24.1 g, what mass of oxygen combined with the iron?

Answer 30

(a) Increased as it would have combined with oxygen in the air thus increasing the amount of matter and therefore the mass. (b) 0.9 g

Question 31

As stated in the text, convincing examples that demonstrate the law of conservation of matter outside of the laboratory are few and far between. Indicate whether the mass would increase, decrease, or stay the same for the following scenarios where chemical reactions take place:
(a) Exactly one pound of bread dough is placed in a baking tin. The dough is cooked in an oven at 350 degrees Fahrenheit releasing a wonderful aroma of freshly baked bread during the cooking process. Is the mass of the baked loaf less than, greater than, or the same as the one pound of original dough? Explain.
(b) When magnesium burns in air a white flaky ash of magnesium oxide is produced. Is the mass of magnesium oxide less than, greater than, or the same as the original piece of magnesium? Explain.
(c) Antoine Lavoisier, the French scientist credited with first stating the law of conservation of matter, heated a mixture of tin and air in a sealed flask to produce tin oxide. Did the mass of the sealed flask and contents decrease, increase, or remain the same after the heating?

Answer 31

(a) When bread dough is baked, it undergoes a chemical reaction. During this process, water and other volatile substances are released as gases, which escape into the air. Therefore, the mass of the baked loaf will be less than the original one pound of dough because some of the mass is lost as gas.
(b) When magnesium burns in air, it reacts with oxygen to form magnesium oxide. The mass of magnesium oxide will be greater than the original piece of magnesium because it includes the mass of the oxygen that has combined with the magnesium.
(c) In Lavoisier’s experiment, the mixture of tin and air is heated in a sealed flask. Since the flask is sealed, no matter can enter or leave the system. Therefore, the mass of the sealed flask and its contents will remain the same after heating, demonstrating the law of conservation of matter.

Question 32

Yest converts glucose to ethanol and carbon dioxide during anaerobic fermentation as depicted in the simple chemical equation here:
glucose —-> ethanol + carbon dioxide
(a) If 200.0 g of glucose is fully converted, what will be the total mass of ethanol and carbon dioxide produced?
(b) If the fermentation is carried out in an open container, would you expect the mass of the container and contents after fermentation to be less than, greater than, or the same as the mass of the container and contents before fermentation? Explain.
(c) If 97.7 g of carbon dioxide is produced, what mass of ethanol is produced?

Answer 32

(a) According to the law of conservation of mass, the total mass of the reactants equals the total mass of the products. Therefore, if 200.0 g of glucose is fully converted, the total mass of ethanol and carbon dioxide produced will also be 200.0 g.; (b) The mass of the container and content would decrease as carbon dioxide is a gaseous product and would leave the container. (c) 102.3 g