Question

1. which of the following is a heterogeneous mixture?

a. air
b. soil
c. salt water
d. steel

1. a cup holds 125 grams of liquid water and 100 grams of ice. what is a reasonable mass for the water in the cup after the ice melts?

a. 175g
b. 215g
c. 225g
d. 230g

1. how does water change as it evaporates?

a. its mass and volume decrease.
b. its mass and volume increase.
c. its mass remains unchanged. its volume increases.
d. its mass increases. its volume remains unchanged

1. which of the following is a heterogeneous mixture?

a. air
b. milk
c. vinegar in water
d. oil and vinegar

1. which of the following is a homogeneous mixture?

a. soil
b. salt water
c. beef stew
d. sand and water

Explanation:

1. A heterogeneous mixture has visibly different parts. Soil has various components like rocks, organic matter etc. that are distinguishable, while air, salt - water and steel are homogeneous.
2. According to the law of conservation of mass, when ice melts into water, the total mass of water in the cup is the sum of the mass of liquid water and the mass of ice. So, \(125 + 100=225\) grams.
3. When water evaporates, water molecules escape into the air. So both the amount of water (mass) and the space it occupies (volume) decrease.
4. Oil and vinegar do not mix uniformly and form distinct layers, making it a heterogeneous mixture. Air, milk (homogenized milk is homogeneous but regular milk can be considered heterogeneous with fat globules), and vinegar in water are more homogeneous.
5. Salt water has a uniform composition throughout as salt dissolves evenly in water. Soil, beef stew and sand - water are heterogeneous mixtures.

Answer:

1. b. soil
2. c. 225g
3. a. Its mass and volume decrease.
4. d. oil and vinegar
5. b. salt water