Laboratory Equipment and Procedure
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AP Chemistry › Laboratory Equipment and Procedure
Which choice of lab equipment is never used to make accurate volume measurements?
Beaker
Graduated cylinder
Burette
Volumetric flask
Explanation
Graduated cylinders are often used for measuring volumetric quantities. As these have several markings, they are considered accurate. Volumetric flasks are also used to accurately measure liquid volume quantities. Lastly, burettes are used to accurately measure volumes of liquid during titrations.
In contrast, beakers are not typically used to measure accurate quantities of liquid; though they have markings on them, these are approximate measurements. Graduated cylinders are often used to accurately measure out a liquid, and beakers to then hold the liquid.
While conducting an experiment, you are required to measure out exactly 
Analytical balance
Centigram balance
Erlenmeyer flask
Triple beam balance
Explanation
Potassium hydrogen phthalate is a solid at room temperature, so we can use a balance and a weigh boat or weigh paper. When measuring precise amounts of chemicals, an analytical balance will be able to provide the most accurate reading of mass.
While conducting an experiment, you are required to measure out exactly
Analytical balance
Centigram balance
Erlenmeyer flask
Triple beam balance
Explanation
Potassium hydrogen phthalate is a solid at room temperature, so we can use a balance and a weigh boat or weigh paper. When measuring precise amounts of chemicals, an analytical balance will be able to provide the most accurate reading of mass.
Using the target shown, determine whether the shots were accurate and/or precise.
Precise but not accurate
Precise and accurate
Neither precise nor accurate
Accurate but not precise
Explanation
The target is precise because the shots are closely grouped together. However, the shots are not accurate because they are not in the middle of the target.
Using the target shown, determine whether the shots are accurate and/or precise.
Neither accurate nor precise
Accurate but not precise
Accurate and precise
Precise but not accurate
Explanation
The shots are not precise because they are not grouped together. However, one of the shots is in the center of the target, and thus is accurate.
Using the target shown, determine whether the shots were accurate and/or precise.
Precise but not accurate
Precise and accurate
Neither precise nor accurate
Accurate but not precise
Explanation
The target is precise because the shots are closely grouped together. However, the shots are not accurate because they are not in the middle of the target.
Using the target shown, determine whether the shots are accurate and/or precise.
Neither accurate nor precise
Accurate but not precise
Accurate and precise
Precise but not accurate
Explanation
The shots are not precise because they are not grouped together. However, one of the shots is in the center of the target, and thus is accurate.
You have a stock solution of 12M HCl, but want to dilute it to 1M HCl. What is the safest way you could go about doing this?
Measure out the water first, then slowly add the correct amount of 12M HCl
Measure out the water first, then rapidly add the correct amount of 12M HCl
Measure out the 12M HCl first, then slowly add the correct amount of water
Measure out the 12M HCl first, then rapidly add the correct amount of water
Add the correct amount of water and 12M HCl to a common beaker at the same time
Explanation
Always add acid to water. You should mix solutions slowly because you run the risk of solutions spilling, which may ruin your reaction entirely. Rapid mixing can also lead to inadvertently speeding up reactions and releasing energy or heat in a dangerous manner. During dilution of acids with, water heat is released; if a small amount of water is added to a concentrated acid it has the possibility of bubbling over the counter and onto you.
You have a stock solution of 12M HCl, but want to dilute it to 1M HCl. What is the safest way you could go about doing this?
Measure out the water first, then slowly add the correct amount of 12M HCl
Measure out the water first, then rapidly add the correct amount of 12M HCl
Measure out the 12M HCl first, then slowly add the correct amount of water
Measure out the 12M HCl first, then rapidly add the correct amount of water
Add the correct amount of water and 12M HCl to a common beaker at the same time
Explanation
Always add acid to water. You should mix solutions slowly because you run the risk of solutions spilling, which may ruin your reaction entirely. Rapid mixing can also lead to inadvertently speeding up reactions and releasing energy or heat in a dangerous manner. During dilution of acids with, water heat is released; if a small amount of water is added to a concentrated acid it has the possibility of bubbling over the counter and onto you.
Which procedure separates two substances using their different boiling points?
Distillation
Filtration
Dehydration
Hydration
Fermentation
Explanation
During the distillation process, the combined substances are heated until the first one boils. The substance that boils and becomes a gas is then separated from the still liquid or solid substance via condensation into a separate container. Filtration involves separating substances in solid and liquid phases through a filter paper, and is often facilitated by a vacuum. Dehydration and hydration are types of reactions where water is a product, and a reactant, respectively. Fermentation is a biochemical process that occurs under anaerobic conditions. Some organisms produce lactic acid as a byproduct of fermentation, (humans), others produce ethanol (yeast).