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Questions and Answers
In the chemistry laboratory, specific apparatus are needed to measure time, temperature, mass, and ______.
In the chemistry laboratory, specific apparatus are needed to measure time, temperature, mass, and ______.
volume
The SI unit for time is the ______.
The SI unit for time is the ______.
second
The temperature of a substance is measured using a ______.
The temperature of a substance is measured using a ______.
thermometer
The SI unit for temperature is the ______.
The SI unit for temperature is the ______.
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Electronic balances have an accuracy of about ±______ g.
Electronic balances have an accuracy of about ±______ g.
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Smaller volumes are measured in cubic decimetres (dm³) or cubic ______.
Smaller volumes are measured in cubic decimetres (dm³) or cubic ______.
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Longer intervals of time are measured in minutes (min) or ______.
Longer intervals of time are measured in minutes (min) or ______.
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1.25 liters is the same as ______ cm³.
1.25 liters is the same as ______ cm³.
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A ______ can be used to measure the volume of a gas liberated during a chemical reaction.
A ______ can be used to measure the volume of a gas liberated during a chemical reaction.
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The process of separating a soluble solid from an insoluble solid using a suitable solvent is known as ______.
The process of separating a soluble solid from an insoluble solid using a suitable solvent is known as ______.
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To separate dry ice from common salt, we use the method of ______.
To separate dry ice from common salt, we use the method of ______.
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The insoluble solid remains in the filter funnel as residue during ______.
The insoluble solid remains in the filter funnel as residue during ______.
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A mixture of seawater can produce sea salt through the process of ______.
A mixture of seawater can produce sea salt through the process of ______.
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Measuring the melting point of a pure solid is an example of a ______ experiment.
Measuring the melting point of a pure solid is an example of a ______ experiment.
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The method of collecting gases lifted from a chemical reaction can include ______ delivery.
The method of collecting gases lifted from a chemical reaction can include ______ delivery.
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The liquid with the lowest boiling point is distilled ______.
The liquid with the lowest boiling point is distilled ______.
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Fractional distillation is used to separate ______ into various useful fractions.
Fractional distillation is used to separate ______ into various useful fractions.
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The boiling point of ______ gas is -152°C.
The boiling point of ______ gas is -152°C.
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______ gas will distil out first because it has the lowest boiling point.
______ gas will distil out first because it has the lowest boiling point.
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Ethanol vaporises more ______, producing more ethanol vapour in the vapour phase.
Ethanol vaporises more ______, producing more ethanol vapour in the vapour phase.
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Chromatography is used to separate two or more ______ in a mixture.
Chromatography is used to separate two or more ______ in a mixture.
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A ______ funnel is used to separate two immiscible liquids.
A ______ funnel is used to separate two immiscible liquids.
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In a separating funnel, the denser liquid ______ to the bottom.
In a separating funnel, the denser liquid ______ to the bottom.
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More soluble substances move at a ______ rate in chromatography.
More soluble substances move at a ______ rate in chromatography.
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Copper(II) oxide is ______ in water.
Copper(II) oxide is ______ in water.
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A pure substance will produce ______ spot on the chromatogram.
A pure substance will produce ______ spot on the chromatogram.
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The more volatile liquid is the first to reach the top of the ______ column.
The more volatile liquid is the first to reach the top of the ______ column.
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An impure substance will produce more than ______ spot on the chromatogram.
An impure substance will produce more than ______ spot on the chromatogram.
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The procedure for chromatography involves drawing a line with a ______ on filter paper.
The procedure for chromatography involves drawing a line with a ______ on filter paper.
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When all the ethanol has distilled over, the temperature will ______ again.
When all the ethanol has distilled over, the temperature will ______ again.
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The first step in the chromatography process is to cut a ______-cm strip of filter paper.
The first step in the chromatography process is to cut a ______-cm strip of filter paper.
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A mixture of amino acids can be separated by using ______ chromatography.
A mixture of amino acids can be separated by using ______ chromatography.
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Amino acids are ______ substances.
Amino acids are ______ substances.
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A locating agent called ______ is sprayed to help visualize the amino acids on the chromatogram.
A locating agent called ______ is sprayed to help visualize the amino acids on the chromatogram.
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The retention factor, or ______, is defined as the ratio of the distance moved by a component to the distance moved by the solvent front.
The retention factor, or ______, is defined as the ratio of the distance moved by a component to the distance moved by the solvent front.
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To identify the amino acids in the mixture, calculated R values must be compared to those in a ______.
To identify the amino acids in the mixture, calculated R values must be compared to those in a ______.
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One of the uses of paper chromatography is to detect ______ of products.
One of the uses of paper chromatography is to detect ______ of products.
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The start line on the chromatography paper should be drawn with a ______ rather than a ballpoint pen.
The start line on the chromatography paper should be drawn with a ______ rather than a ballpoint pen.
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If the solvent overshoots the top of the paper, accurate determination of the distance travelled by the ______ cannot be assessed.
If the solvent overshoots the top of the paper, accurate determination of the distance travelled by the ______ cannot be assessed.
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Pure ______ is used to make silicon chips for making microprocessors.
Pure ______ is used to make silicon chips for making microprocessors.
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Pure ______ is needed to make copper wires used in electrical wiring.
Pure ______ is needed to make copper wires used in electrical wiring.
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The melting point of pure tin is ______ °C.
The melting point of pure tin is ______ °C.
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The presence of an impure substance will ______ the melting point of a pure substance.
The presence of an impure substance will ______ the melting point of a pure substance.
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The mixture of tin and lead with the lowest melting point contains ______% tin and ______% lead.
The mixture of tin and lead with the lowest melting point contains ______% tin and ______% lead.
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Methods of separation and purification include techniques such as filtration, ______, and distillation.
Methods of separation and purification include techniques such as filtration, ______, and distillation.
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Paper chromatography can be used to compare 'known' samples and deduce their ______.
Paper chromatography can be used to compare 'known' samples and deduce their ______.
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Study Notes
Experimental Design - Measurement
- Specific laboratory equipment is needed for measuring time, temperature, mass, and volume
- The International System of Units (SI units) is used for recording measurements
- Time intervals are measured using stopwatches (analogue or digital)
- The SI unit for time is the second (s)
- Longer time intervals are measured in minutes (min) or hours (h)
- Analogue stopwatches measure with an accuracy of ±0.1 s
- Digital stopwatches measure with an accuracy of ±0.01 s
- Temperature is measured using thermometers (analogue or digital)
Experimental Design - Temperature
- The temperature of a substance is measured using a thermometer
- Analogue and digital thermometers are both used
- The SI unit for temperature is the kelvin (K)
- Another common unit for temperature is the degree Celsius (°C)
- The Kelvin scale starts at absolute zero (0 K), never negative
- The Celsius scale is based on 0 °C for the freezing point of water and 100 °C for boiling point of water
- To convert Celsius to Kelvin: K = °C + 273
Experimental Design - Mass
- Mass is measured using electronic balances, chemical balances, or beam balances
- The SI unit for mass is the kilogram (kg)
- Smaller masses are measured in grams (g) or milligrams (mg), while larger masses are measured in tonnes (t)
- Electronic balances typically have an accuracy of ±0.01 g
Experimental Design - Volume
- The SI unit for volume is the cubic meter (m³)
- Smaller volumes are measured in cubic decimeters (dm³) or cubic centimeters (cm³)
- Measuring equipment includes burettes, measuring cylinders, pipettes, syringes, and volumetric flasks
- The choice of apparatus depends on the volume to be measured and the accuracy required
- A measuring cylinder is used to measure approximate volumes to the nearest 0.5 cm³
- A gas syringe is used to measure gas volumes (up to 100cm³)
- A burette is used to deliver accurate volumes (0-50 cm³ to ±0.05 cm³)
- A pipette is used to deliver fixed volumes (usually 25 cm³)
- A volumetric flask is used for accurate volume measurements
Experimental Design - Methods for Collecting Gases
- Methods for collecting gases during chemical reactions depend on the gas's properties
- By displacement of water (for insoluble gases e.g., hydrogen, nitrogen, oxygen, carbon dioxide)
- By downward delivery (for gases denser than air, e.g., carbon dioxide, sulfur dioxide, hydrogen chloride)
- By upward delivery (for gases less dense than air, e.g., ammonia, hydrogen)
Experimental Design - Drying Gases
- The choice of drying agent depends on the gas properties
- Neutral gases use sulfuric acid or fused calcium chloride
- Acidic gases use sulfuric acid or fused calcium chloride
- Alkaline gases use quicklime (calcium oxide)
Experimental Design - Titration
- Titration is used to determine the concentration of a solution (often an acid-base reaction)
- Equipment includes a burette (50 cm³), burette stand, conical flask, pipette
Experimental Design - Measuring Rates of Reactions
- Measuring the change in volume of a liberated gas over time or measuring the change in mass of a reactant or product over time
- Equipment includes graduated gas syringes, electronic balances, digital stopwatches
Experimental Design - Melting & Boiling Points
- Measuring melting and boiling points to determine the identity of substances. Water cannot be used to heat substances with melting points above 100°C as paraffin oil is typically used instead
- Pure substances have sharp melting and boiling points, while impure substances melt and boil over a range of temperatures. Impurities lower the melting point of substances and elevate the boiling points
Experimental Design - Chromatography
- Chromatography is used to identify substances, determine purity, and separate mixtures
- Different substances travel at different speeds due to varying solubilities in the solvent.
- Paper chromatography is used in the lab with small quantity substances and mixtures with many substances
- A pure substance produces one spot, the impure substance produces more than one spot.
- Paper chromatography is used to separate and identify components in substances like ink and mixtures of amino acids
- The retention factor (Rf) helps identify the components in the solution
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Description
Test your knowledge on the essential apparatus used in the chemistry laboratory. This quiz covers topics such as measurements of time, temperature, mass, and techniques for separating substances. Perfect for chemistry students looking to reinforce their understanding of laboratory practices.
