1.
A mixture is ...
Correct Answer
B. Two or more substances mixed together
Explanation
The correct answer is "Two or more substances mixed together." A mixture is a combination of two or more substances that are physically combined but not chemically bonded. In a mixture, each substance retains its own properties and can be separated through physical means, such as filtration or distillation. This is different from a pure substance, which consists of only one type of particle and cannot be separated into other substances by physical means. Therefore, a mixture is a combination of multiple substances mixed together.
2.
Mixtures can be classified into 2 types, homogeneous and heterogenous. They are different because
Correct Answer
B. Homogeneous looks the same throughout, with heterogenous you can see the different parts
Explanation
The correct answer is that homogeneous mixtures look the same throughout, while heterogeneous mixtures allow you to see the different parts. This is because in homogeneous mixtures, the substances are evenly distributed and cannot be easily distinguished, whereas in heterogeneous mixtures, the substances are not evenly distributed and can be visually identified.
3.
Another name for homogeneous is
Correct Answer
A. Solution
Explanation
A solution is a mixture where the components are evenly distributed, making it homogeneous. Therefore, the correct answer is "solution." A solvent is the substance in which solutes dissolve, solute is the substance being dissolved, and saline refers specifically to a solution containing salt.
4.
To separate a mixture of sand and iron it is easiest to use
Correct Answer
C. A magnet
Explanation
A magnet is the easiest way to separate a mixture of sand and iron because iron is magnetic, while sand is not. By using a magnet, the iron particles can be attracted and separated from the sand particles, allowing for a quick and efficient separation process.
5.
Solutions are made of at least 2 parts called
Correct Answer
B. Solute and solvent
Explanation
A solution is a homogeneous mixture composed of two or more substances. The solute is the substance that is dissolved in the solution, while the solvent is the substance that dissolves the solute. Therefore, the correct answer is "solute and solvent" as these are the two essential components of a solution.
6.
I'm making soup for lunch. Which would be faster, rock salt or regular table salt?
Correct Answer
B. Table salt
Explanation
Table salt is smaller than rock salt. Since they are the same substance (salt), the only difference is the size of the particle. From your experiment with powdered sugar and the sugar cube, you know that smaller particle sizes dissolve faster than larger particle sizes.
7.
Which of the following is a chemical change?
Correct Answer
C. Rusting of iron
Explanation
A chemical change results in the formation of new substances with different properties. Rusting of iron is a chemical change because it involves iron reacting with oxygen and water to form a new substance, iron oxide (rust). Melting of ice and dissolving sugar in water are physical changes because no new substances are formed. Cutting a piece of paper is also a physical change as it only alters the shape of the paper, not its chemical composition.
8.
Which of the following are homogeneous mixtures?
Correct Answer(s)
A. Water
C. Shampoo
Explanation
Homogeneous mixtures are uniform throughout, meaning that the components are evenly distributed and not easily distinguishable. Water and shampoo both fit this description as they are single-phase mixtures where the substances are evenly distributed at a molecular level. On the other hand, rocky road ice cream and oatmeal are not homogeneous mixtures as they contain visibly distinct components, such as chocolate chunks and marshmallows in ice cream, and different-sized oat flakes in oatmeal.
9.
Which of the following are mechanical mixtures?
Correct Answer(s)
A. Chocolate bar with almonds
D. Orange juice with pulp
Explanation
A mechanical mixture is a mixture where the different components can be easily distinguished and separated. In the case of a chocolate bar with almonds, the chocolate and almonds are clearly visible and can be separated if desired. Similarly, orange juice with pulp is a mechanical mixture because the pulp is visible and can be separated from the juice. On the other hand, chocolate milk and flat pop are not mechanical mixtures as the components (milk and chocolate, carbonated water and flavorings) are not easily distinguishable and cannot be separated easily.
10.
What happens when you try to make a solution of salt and oil?
Correct Answer
B. It becomes a heterogeneous mixture, the salt doesn't dissovle into the oil
Explanation
When you try to make a solution of salt and oil, it becomes a heterogeneous mixture because the salt does not dissolve into the oil. Unlike water, oil is not a polar solvent, so it cannot dissolve the polar molecules of salt. Therefore, the salt particles remain separate and do not mix evenly with the oil, resulting in a heterogeneous mixture.
11.
To separate a solution of black pepper and salt...
Correct Answer
C. Add water, filter out the pepper, boil off the water to get salt
Explanation
The salt will dissolve in the water, pepper will not. It is too hard to separate the salt and pepper because they are both so small.
12.
Another name for homogeneous is
Correct Answer
A. Solution
Explanation
Homogeneous refers to a substance that has a uniform composition throughout. A solution is a type of homogeneous mixture where a solute is dissolved in a solvent. Therefore, solution is another name for homogeneous. Solute refers to the substance being dissolved, solvent refers to the substance doing the dissolving, and saline refers to a specific type of solution containing salt.
13.
Solutions are made of at least 2 parts called
Correct Answer
A. Solute and solvent
Explanation
A solution is a homogeneous mixture composed of two or more substances. The solute is the substance that is dissolved in the solvent, while the solvent is the substance that dissolves the solute. Therefore, the correct answer is "solute and solvent."
14.
How is mass different than weight?
Correct Answer
D. Mass is the amount of matter and weight is the amount of matter plus gravity.
Explanation
Mass and weight are not the same thing. Mass refers to the amount of matter an object contains, while weight is the force exerted on an object due to gravity. Mass remains constant regardless of the location of the object, while weight can vary depending on the strength of the gravitational pull.
15.
You are given a mystery object in science class. Your teacher asks you to determine if your object is more or less dense than water. You place the object in the water and it sinks. What statement would best describe this situation?
Correct Answer
A. The mystery substance is denser than water.
Explanation
The fact that the mystery object sinks when placed in water indicates that it is denser than water. Objects with higher density than the liquid they are placed in will sink, while objects with lower density will float. Therefore, the statement "The mystery substance is denser than water" best describes the situation.