page 39 #1-9
1. Every sample of a given substance has the same chemical composition.
2.solid,liquid,gas
3. Physical changes are either reversible or irreversible. Reversible changes can be undone, or reversed. Irreversible changes cannot be undone.
4.intensive and extensive properties.
5. Color;sodium chloride is the only white solid listed.
6. Gases are compressible,but solids and liquids are relatively incompressible. Solids have a rigid, closely packed structure. Liquids also have structures consisting of particles that are close together, but the particles are free to flow past one another. In gases, the particles are relatively far apart and move freely. The shape of a solid is definite, while liquids take the shape of a portion of the container, and gases take the shape of the entire container. Solids and liquids have definite volume. Gases expand to fill the entire volume of the container.
7. The freezing of mercury is reversible because solid mercury can be melted.
8. Samples of platinum and copper can have the same mass and volume (extensive properties). They cannot have the same set of intensive properties, such as melting point or density, because they have different chemical compositions.
9. Sample answers: choosing materials for automobile parts; combining and cooking foods in a restaurant; handling product for cleaning and maintaining swimming pools.
page 43 #12-19
12. as heterogeneous or homogeneous
13. difference in physical properties
14. A phase is any part of a sample with uniform composition. A homogeneous mixture has one phase, a heterogeneous mixture has two more phases.
15. a homogeneous
b. heterogeneous
c.homogeneous
d.heterogeneous
16. Both have a uniform composition throughout. A substance has a definite composition; a solution has a variable composition.
17. Filtration separates solids from a liquid in a heterogeneous mixture. Distillation can be separate a liquid from substances dissolved in the liquid.
18. Add water to dissolve the salt. Filter the mixture to remove the sand. Evaporate the water from the liquid to isolate the solid salt.
19 Sample answers; example of mixtures at home including sorting laundry, draining cooked pasta, putting away bags of groceries.
page 49 #22-31
22. Compounds can be broken down into simpler substances by chemical means, but elements cannot.
23. A substance has a fixed composition. The composition of a mixture may vary.
24. Chemical symbols are used to represent elements. Chemical formulas are used to represent compounds.
25. It allows you to compare the properties of the elements.
26. Sample answer: heating, an electric current
27. a. compound
b.mixture
c.mixture
d.element
28.a. Pb
b. O
c. Ag
d. Na
e. H
f. Al
29. a. carbon
b. calcium
c.potassium
d. gold
e. iron
f. copper
30. carbon, hydrogen, oxygen, and nitrogen; hydrogen is present in the greatest proportion by number of particles.
31. Any two beryllium (Be), magnesium (Mg), strontium (Sr), barium (Ba), radium (Ra)
1. Every sample of a given substance has the same chemical composition.
2.solid,liquid,gas
3. Physical changes are either reversible or irreversible. Reversible changes can be undone, or reversed. Irreversible changes cannot be undone.
4.intensive and extensive properties.
5. Color;sodium chloride is the only white solid listed.
6. Gases are compressible,but solids and liquids are relatively incompressible. Solids have a rigid, closely packed structure. Liquids also have structures consisting of particles that are close together, but the particles are free to flow past one another. In gases, the particles are relatively far apart and move freely. The shape of a solid is definite, while liquids take the shape of a portion of the container, and gases take the shape of the entire container. Solids and liquids have definite volume. Gases expand to fill the entire volume of the container.
7. The freezing of mercury is reversible because solid mercury can be melted.
8. Samples of platinum and copper can have the same mass and volume (extensive properties). They cannot have the same set of intensive properties, such as melting point or density, because they have different chemical compositions.
9. Sample answers: choosing materials for automobile parts; combining and cooking foods in a restaurant; handling product for cleaning and maintaining swimming pools.
page 43 #12-19
12. as heterogeneous or homogeneous
13. difference in physical properties
14. A phase is any part of a sample with uniform composition. A homogeneous mixture has one phase, a heterogeneous mixture has two more phases.
15. a homogeneous
b. heterogeneous
c.homogeneous
d.heterogeneous
16. Both have a uniform composition throughout. A substance has a definite composition; a solution has a variable composition.
17. Filtration separates solids from a liquid in a heterogeneous mixture. Distillation can be separate a liquid from substances dissolved in the liquid.
18. Add water to dissolve the salt. Filter the mixture to remove the sand. Evaporate the water from the liquid to isolate the solid salt.
19 Sample answers; example of mixtures at home including sorting laundry, draining cooked pasta, putting away bags of groceries.
page 49 #22-31
22. Compounds can be broken down into simpler substances by chemical means, but elements cannot.
23. A substance has a fixed composition. The composition of a mixture may vary.
24. Chemical symbols are used to represent elements. Chemical formulas are used to represent compounds.
25. It allows you to compare the properties of the elements.
26. Sample answer: heating, an electric current
27. a. compound
b.mixture
c.mixture
d.element
28.a. Pb
b. O
c. Ag
d. Na
e. H
f. Al
29. a. carbon
b. calcium
c.potassium
d. gold
e. iron
f. copper
30. carbon, hydrogen, oxygen, and nitrogen; hydrogen is present in the greatest proportion by number of particles.
31. Any two beryllium (Be), magnesium (Mg), strontium (Sr), barium (Ba), radium (Ra)