0973 12 Experimental techniques and chemical analysis CORE

What are compounds?

• Substances that contain two or more elements that are chemically combined in fixed proportions

• Elements that cannot be broken down into simpler substances

• Mixtures of different substances that retain their individual properties

• Pure substances that consist of only one type of atom

How do the chemical properties of a substance change when it’s in a mixture?

• The chemical properties of a substance don't change

• The chemical properties become more reactive

• The chemical properties are completely altered

• The chemical properties are enhanced

How can you test for oxygen (O₂)?

• Use a glowing splint; it will reignite in the presence of oxygen.

• Use a lit match; it will extinguish in the presence of oxygen.

• Use a colorless gas; it will turn blue in the presence of oxygen.

• Use a burning candle; it will burn brighter in the presence of oxygen.

What apparatus is commonly used to measure temperature?

• Thermometer

• Barometer

• Anemometer

• Hydrometer

How is the melting and boiling point of an impure substance affected?

• m.p. decreases, b.p. increases

• m.p. increases, b.p. decreases

• m.p. remains the same, b.p. increases

• m.p. decreases, b.p. remains the same

What apparatus is used to collect and measure the volume of gas produced in a reaction?

• Gas syringe

• Beaker

• Test tube

• Burette

In paper chromatography, what is the solvent front?

• a line that marks the furthest point along the chromatography paper that the solvent reached

• the point where the sample is applied on the chromatography paper

• the area where the solvent evaporates

• the line that indicates the start of the chromatography process

What can sodium hydroxide solution be used to test for?

• certain metal ions (cations) in a solution

• pH levels in a solution

• the presence of organic compounds

• the boiling point of liquids

What is simple distillation used to separate?

• A liquid from a solid

• A gas from a liquid

• A solid from a solid

• A liquid from a gas

What method can be used to separate an insoluble solid from a liquid?

• Filtration

• Evaporation

• Distillation

• Centrifugation