1.
To get salt out of a solution (separating salt from water) we could try.....
Correct Answer
B. Distilling the solution
Explanation
The most effective method to separate salt from water is to distill the solution. This process involves heating the solution, causing the water to turn into vapor and leave the salt behind. As the water evaporates, the salt crystals become more concentrated until they are left as a solid residue. This method takes advantage of the difference in boiling points between water and salt, allowing for the separation of the two substances. The water vapor then condenses on the cold finger of the distillation apparatus and then drips down into a collection flask, allowing pure water to be recovered.
2.
If Jo wants to get the iron filings out of some sand, what could she use to separate these two solids?
Correct Answer
A. A magnet
Explanation
Jo can use a magnet to separate the iron filings from the sand because iron is magnetic. By running a magnet through the mixture, the iron filings will be attracted to the magnet and can be easily separated from the sand. This method is effective for separating mixtures of solids when one of the components is magnetic.
3.
Evaporation means going from a liquid to a ____________.[Choose from: liquid, solid, gas]
Correct Answer
gas
Explanation
Evaporation is the process by which a liquid changes into a gas. This occurs when the molecules of the liquid gain enough energy to break free from their intermolecular bonds and escape into the air. Therefore, the correct answer is gas.
4.
Melting means going from a __________ to a liquid.[Choose from: liquid, solid, gas]
Correct Answer
solid
Explanation
Melting is the process by which a solid substance changes into a liquid state. When a solid is heated to its melting point, the particles gain enough energy to overcome the forces holding them in a fixed arrangement, causing them to move more freely and become a liquid. Therefore, the correct answer is "solid".
5.
Condensing means going from a gas to a ____________.[Choose from: liquid, solid, gas]
HINT! Dew is water condensing out of the air onto the grass.
Correct Answer
liquid
Explanation
When a substance condenses, it changes its physical state from a gas to a liquid. This process typically occurs when the temperature of the gas is lowered, causing the gas particles to lose energy and come closer together, forming a liquid.
6.
Freezing means going from a liquid to a ____________.[Choose from: liquid, solid, gas]
Correct Answer
solid
Explanation
When a substance freezes, it undergoes a phase change from a liquid state to a solid state. The particles in the substance slow down and come closer together, forming a rigid structure. This is why the correct answer is "solid".
7.
If I pour the water off after I boil the potatoes, what is this an example of?
[I am separating the solid potatoes from the liquid hot water]
Correct Answer
D. Decanting
Explanation
This is an example of decanting. Decanting is the process of carefully pouring off a liquid from a mixture, while leaving the solid behind. In this case, after boiling the potatoes, the hot water is being separated from the solid potatoes by pouring off the water.
8.
I am making lip balm. I have to pour my cooked mixture through some muslin (fabric). What am I doing to the mixture?
[I am separating the solid bits from the liquid bits: the liquid can fit through the tiny holes in the muslin fabric]
Correct Answer
C. Filtering it
Explanation
The process described involves passing the cooked mixture through muslin fabric, which acts as a filter. The tiny holes in the fabric allow the liquid portion of the mixture to pass through while separating the solid bits. Therefore, the correct answer is "filtering it."
9.
I put dirty water into a funnel with a paper lining. Clean water comes out of the funnel into my beaker and solid dirt gets left behind on the paper. This is an example of ____________
Correct Answer
Filtration, filtering, filtration, Filtering
Explanation
Filtration is a process used to separate solids from liquids by passing the mixture through a filter, like the paper lining in this case. The solid dirt is trapped by the filter paper, while the clean water passes through into the beaker. This is a common method for separating mixtures based on particle size.
10.
When rain falls, this is because the water vapor in the clouds is condensing into liquid _________?
Correct Answer
C. Water
Explanation
When rain falls, it is because the water vapor in the clouds is condensing into liquid water. Water vapor, which is the gaseous form of water, rises into the atmosphere and when it cools down, it condenses back into liquid form. This process forms clouds, and when the water droplets in the clouds become too heavy, they fall as rain. Therefore, the correct answer is water.
11.
Which of the following is NOT a mixture?
Correct Answer
A. Water
Explanation
Water is not a mixture because it is a pure substance. A pure substance consists of only one type of atom or molecule, and water is made up of only water molecules (H2O). In contrast, the other options listed are mixtures because they are composed of multiple substances. Hot chocolate made with milk is a mixture of milk, cocoa powder, sugar, and other ingredients. Coffee made with hot water is a mixture of coffee beans and water. A boiled sweet is a mixture of sugar, flavorings, and other ingredients.
12.
Which of the following mixtures could NOT be separated into its components by DECANTING?
Correct Answer
C. Coffee made in hot water
Explanation
Decanting is a process of separating a mixture by pouring off the liquid component, leaving behind the solid component. In the case of coffee in hot water, the coffee beans are extracted by water, forming a homogeneous mixture of coffee bean extract in water. Since the coffee extract is dissolved in the hot water, the water and coffee extract cannot be separated by decanting only.
13.
If salt has been dissolved in water, how could I separate it from the water again?
Correct Answer
B. By evaporating the water
Explanation
Evaporating the water is a correct method to separate salt from water. This process involves heating the saltwater solution to allow the water to evaporate, leaving behind the salt as a solid residue.
14.
Which of these are methods of separating a solid from a liquid?
Correct Answer
B. Decanting, filtering and evaporating
Explanation
Decanting, filtering, and evaporating are all methods of separating a solid from a liquid. Decanting involves carefully pouring off the liquid while leaving the solid behind. Filtering uses a filter to separate the solid particles from the liquid. Evaporating involves heating the mixture to a point where the liquid evaporates, leaving behind the solid. Dissolving, on the other hand, is not a method of separating a solid from a liquid but rather a process where a solid dissolves into a liquid to form a solution.
15.
Which of these methods could be used to separate an insoluble solid from a soluble solid.
[HINT: soluble means WILL dissolve; insoluble means WON'T dissolve]
Correct Answer
A. Mixing the mixture with water and then filtering it. Then we could evaporate the water from the resulting liquid.
Explanation
The method of mixing the mixture with water and then filtering it allows the insoluble solid to be separated from the soluble solid. This is because the soluble solid will dissolve in water, forming a solution, while the insoluble solid will remain as a solid. By filtering the mixture, the insoluble solid can be retained on the filter paper while the soluble solid passes through as a solution. Evaporating the water from the resulting liquid will then allow the soluble solid to be recovered in its solid form, leaving behind the insoluble solid.