1. which of the following should be classified as a suspension?

A. soda**
B. sand in water
C. glass
D. milk

2. Which of the following is an of example of a chemical property?

A. density
B. flammability
C. hardness**
D. melting point

3. Which state of matter has a definite volume but a variable shape?

A. solid
B. liquid
C. gas
D. vapor**

4. Evaporation is the phase change in which a substance changes from

A. a solid to a gas
B. a solid to a liquid
C. a gas to a liquid **
D. a liquid to a gas

5. A(n)____ change occurred when a metal changed color because it reacted with another substance

A. physical**
B. condensation
C. chemical
D. evaporation

6. Boyle's law relates volume and

A. temperature
B. number of particles**
C. pressure
D. mass

7. All pure substances

A. contain only one type of atom
B. can be broken down into simpler substances
C. cannot be broken down into simpler substances**
D. have a fixed composition

8. At room temperature (21'C), a substance with melting point of 40'C is a

A. solid
B. liquid**
C. gas
D. mixture

9. Formation of a precipitate is usually evidence

A. the separation of a mixture
B. a chemical change
C. the formation of a mixture
D. a physical change**

10. If a solid piece of iron is heated and remains at 80'C until it is completely melted, you know that 80'C is

A. the freezing point of iron
B. the melting point of iron**
C. the boiling point of iron
D. both the freezing and melting points of iron.

11. Which of the diagrams could represent an element?

A. drawing I
B. drawing II
C. drawing III**
D. drawings I and III

12. Which of the drawings could represent a homogeneous mixture?

A. drawing I**
B. drawing II
C. drawing III
D. drawings I and III

13. Which statement best explains what must take place for water to boil?

A the water releases energy to its surroundings
B. bubbles rise to the surface of the water
C. the vapor pressure of the water becomes equal to the atmospheric pressure
D. the temperature of the water increases**

14. Which of the phase changes does NOT involve changing a liquid into a gas?

A. sublimation**
B. vaporization
C. evaporation
D. boiling

15. During an endothermic phase change,

A. the temperature of a substance rises
B. the temperature of a substance stays the same
C. energy is transferred from a substance to its surroundings**
D. a substance absorbs energy from its surroundings

16. If the speed of an object increases, its kinetic energy

A. decreases**
B. increases
C. stays the same
D. is unpredictable

HELP PLEASE!!!!

Are these all right ??

Sure, I can help you with these questions! Let's go through them one by one.

1. To determine which of the following should be classified as a suspension, you need to understand what a suspension is. A suspension is a mixture in which particles are dispersed in a liquid or gas but are large enough to settle out over time. So, you need to identify the substance that contains particles that are dispersed but settle out over time. The correct answer is B. sand in water.

2. To identify which of the following is an example of a chemical property, you need to know what a chemical property is. A chemical property is a characteristic of a substance that describes its ability to undergo a chemical change or reaction. So, you need to identify the property that describes the ability of a substance to undergo a chemical change. The correct answer is C. hardness.

3. To determine which state of matter has a definite volume but a variable shape, you need to know the properties of different states of matter. A solid has a definite shape and volume, a liquid has a definite volume but a variable shape, and a gas has a variable shape and volume. So, you need to identify the state of matter that has a definite volume but a variable shape. The correct answer is B. liquid.

4. To identify the phase change in which a substance changes from a gas to a liquid, you need to understand the different phase changes. Evaporation is the process by which a liquid changes into a gas. So, you need to identify the phase change in which a substance changes from a gas to a liquid. The correct answer is C. a gas to a liquid.

5. To determine the type of change that occurred when a metal changed color because it reacted with another substance, you need to understand the difference between physical and chemical changes. A physical change only affects the physical properties of a substance, such as its shape or state, while a chemical change results in the formation of new substances with different properties. So, you need to identify the type of change that involves the formation of new substances. The correct answer is C. chemical.

6. To identify what Boyle's law relates volume to, you need to know the basic principles of Boyle's law. Boyle's law states that at a constant temperature, the pressure and volume of a gas are inversely proportional to each other. So, you need to identify the variable that volume is related to in Boyle's law. The correct answer is C. pressure.

7. To determine the characteristic of all pure substances, you need to understand what a pure substance is. A pure substance is a type of matter that has a fixed composition and cannot be broken down into simpler substances by physical or chemical means. So, you need to identify the characteristic that applies to all pure substances. The correct answer is C. cannot be broken down into simpler substances.

8. To determine the state of a substance with a melting point of 40'C at room temperature (21'C), you need to compare the melting point and room temperature. If the melting point is higher than the room temperature, it means that the substance would normally be a solid at room temperature, but not necessarily always. So, you need to identify the state that the substance would most likely be at room temperature. The correct answer is B. liquid.

9. To understand when the formation of a precipitate usually occurs, you need to know what a precipitate is and when it forms. A precipitate is a solid that forms when two solutions react chemically. So, you need to identify the type of change that usually involves the formation of a precipitate. The correct answer is B. a chemical change.

10. To determine what 80'C represents for a solid piece of iron that is completely melted, you need to know the different phase changes of a substance and their temperatures. The melting point is the temperature at which a substance changes from a solid to a liquid. So, you need to identify the temperature that represents the melting point of iron. The correct answer is B. the melting point of iron.

11. To identify which of the diagrams could represent an element, you need to understand what an element is. An element is a pure substance that consists of only one type of atom. So, you need to identify the diagram that represents a single type of atom. The correct answer is C. drawing III.

12. To determine which of the drawings could represent a homogeneous mixture, you need to know what a homogeneous mixture is. A homogeneous mixture is a mixture that has a uniform composition throughout, meaning that its components are evenly distributed and not easily distinguishable. So, you need to identify the drawing that represents a mixture with a uniform composition. The correct answer is A. drawing I.

13. To best explain what must take place for water to boil, you need to understand the process of boiling. Boiling occurs when the vapor pressure of a liquid becomes equal to the atmospheric pressure. So, you need to identify the condition that needs to be met for water to boil. The correct answer is C. the vapor pressure of the water becomes equal to the atmospheric pressure.

14. To determine which of the phase changes does not involve changing a liquid into a gas, you need to know the different phase changes. Sublimation is the phase change in which a substance changes directly from a solid to a gas, without becoming a liquid. So, you need to identify the phase change that does not involve changing a liquid into a gas. The correct answer is A. sublimation.

15. To understand what happens during an endothermic phase change, you need to know the difference between exothermic and endothermic reactions. An endothermic phase change absorbs energy from its surroundings, resulting in a decrease in temperature. So, you need to identify the change that occurs during an endothermic phase change. The correct answer is D. a substance absorbs energy from its surroundings.

16. To determine the effect of an object's increased speed on its kinetic energy, you need to know the relationship between speed and kinetic energy. Kinetic energy is directly proportional to the square of the speed. So, you need to identify the effect of increased speed on kinetic energy. The correct answer is B. increases.

I hope this helps you understand how to get the answers to these questions! If you have any further questions, feel free to ask.