Question

1. which of the following statements is false?

a. atoms found in an element are alike.
b. the atoms of chlorine are the same as the atoms in potassium.
c. magnesium contains many atoms that are alike.
d. compounds contain several different kinds of atoms.

1. which of the following statements is a compound?

a. iron by itself. (fe)
b. sulfur by itself. (s)
c. iron plus sulfur after heating. (fes)
d. iron plus sulfur before heating. fe & s)
how is matter classified?

1. decide whether the sample is a pure substance or a mixture. place an x

in the correct column.
matching:

1. compound
2. element
3. pure substance
4. heterogeneous mixture
5. homogeneous mixture
6. mixture

a. a substance that contains all the same atoms or molecules.
b. two or more different substances are joined together chemically
c. a substance with atoms that are all alike.
d. a substance that contains two or more components that are
blended together so that they appear to be one.
e. a substance that contains two or more different substances that
are not chemically combined.
f. a substance that contains different components that stand out
from one another and can be easily separated from one another.

Explanation:

• Question 10: Atoms of different elements (like chlorine and potassium) are different. Magnesium is an element (all atoms alike). Compounds have different kinds of atoms. So, option B is false as chlorine atoms are different from potassium atoms.
• Question 11: A compound is formed when two or more elements chemically combine. Iron (Fe) and sulfur (S) chemically react when heated to form FeS (a compound). Before heating, it's a mixture. Iron or sulfur alone is an element.
• Question 12:
• Air (\(N_2+CO_2 + O_2\)): Mixture (different gases not chemically combined).
• Copper: Pure substance (element).
• Chef Salad: Mixture (different food items).
• Aluminum (Al): Pure substance (element).
• Sodium Hydroxide (NaOH): Pure substance (compound).
• Sugar Water: Mixture (sugar and water not chemically combined).
• \(HCl + H_2O\): Mixture (if just mixed, not reacting; if reacting, depends on context, but usually considered a mixture of hydrochloric acid solution).
• Question 13 - 18:
• Compound: B (two or more different substances joined chemically).
• Element: C (atoms all alike).
• Pure substance: A (all same atoms/molecules).
• Heterogeneous mixture: F (components stand out).
• Homogeneous mixture: D (components blended to appear one).
• Mixture: E (different substances not chemically combined).

Answer:

1. B. The atoms of chlorine are the same as the atoms in potassium.
2. C. Iron plus sulfur after heating. (FeS)

12.

• Air (\(N_2+CO_2 + O_2\)): Mixture
• Copper: Pure Substance
• Chef Salad: Mixture
• Aluminum (Al): Pure Substance
• Sodium Hydroxide (NaOH): Pure Substance
• Sugar Water: Mixture
• \(HCl + H_2O\): Mixture

1. B
2. C
3. A
4. F
5. D
6. E