Elements, Compounds & Mixtures Quiz

False (B)

100 ºC

<p>78</p> Signup and view all the answers

<p>Ethanol = Boiling point of 78 ºC Water = Boiling point of 100 ºC Condenser = Cools vapors into liquid Fractional Distillation = Separates miscible liquids</p> Signup and view all the answers

<p>It can be chemically combined with other elements. (C)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>A pure substance made up of two or more elements chemically combined.</p> Signup and view all the answers

<p>mixture</p> Signup and view all the answers

<p>Copper = Element Carbon Dioxide = Compound Salt Water = Mixture Iron = Element</p> Signup and view all the answers

<p>Mixture (C)</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>A compound is chemically combined while a mixture is not.</p> Signup and view all the answers

<p>To separate an undissolved solid from a liquid (C)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>Crystals form on a glass rod dipped into the solution.</p> Signup and view all the answers

<p>residue; filtrate</p> Signup and view all the answers

<p>Filtration = Separation of undissolved solids from liquids Centrifugation = Separation of mixtures using high speed Crystallisation = Separation of dissolved solids from solutions Evaporation = Conversion of liquid to vapor to leave solids behind</p> Signup and view all the answers

<p>Heating the solution to evaporate the solvent (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>They are washed with cold distilled water and allowed to dry.</p> Signup and view all the answers

<p>To separate substances based on their solubilities (A)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>Different solubilities in the solvent.</p> Signup and view all the answers

<p>further</p> Signup and view all the answers

<p>Crystallisation (D)</p> Signup and view all the answers

<p>Chromatography = Technique for separating substances based on solubility Capillary action = Movement of solvent up the paper Soluble solid = Solid that dissolves in a solvent Evaporation = Process of turning liquid into vapor</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>Ink would run into the chromatogram and mix with the samples.</p> Signup and view all the answers

<p>The retention factor of a substance (D)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>Rf = distance moved by substance / distance moved by solvent</p> Signup and view all the answers

<p>1</p> Signup and view all the answers

<p>Rf values have units. (B)</p> Signup and view all the answers

<p>Rf value = A ratio used to identify substances Solvent = The medium that moves the analytes Chromatography = A technique to separate mixtures Retention factor = Another term for Rf value</p> Signup and view all the answers

<p>0.5</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>Use a ruler to draw a horizontal pencil line 2 cm from the end of the chromatography paper (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>2-3 mm</p> Signup and view all the answers

<p>food</p> Signup and view all the answers

<p>2 cm (D)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>solvent front line</p> Signup and view all the answers

A method used to separate liquids with different boiling points from a mixture.

Liquids that can mix together in any proportion.

The temperature at which a liquid turns into a gas.

Equipment used to separate liquids by fractional distillation, including a heating source, a flask, a fractionating column, and a condenser.

Fractional distillation used to separate ethanol and water because they have different boiling points (ethanol 78°C, water 100°C).

A substance made of atoms that all contain the same number of protons, and cannot be split into anything simpler.

A pure substance made up of two or more elements chemically combined.

A combination of two or more substances (elements and/or compounds) that are not chemically combined.

A substance with a fixed composition. Examples: elements and compounds.

All substances can be categorized as either elements, compounds, or mixtures.

Techniques like filtration and evaporation can be used to separate components of a mixture.

A table listing all known elements.

Subatomic particles found in the atom's nucleus.

A method used to separate an undissolved solid from a mixture of the solid and a liquid, like separating sand from water.

The liquid that passes through the filter paper during filtration.

The solid that remains on the filter paper after filtration.

A method used to separate a dissolved solid from a solution by taking advantage of its solubility difference in hot and cold solvents, like separating copper sulphate from water.

A solution containing the maximum amount of solute that can dissolve at a given temperature.

The amount of solute that can dissolve in a given amount of solvent at a specific temperature.

Substances that are present in a mixture but not desired after the separation process.

Washing crystals with cold distilled water helps to remove any impurities that might be clinging to them after filtration. Cold water minimizes further dissolving of the crystals.

A technique used to separate substances based on their different solubilities in a solvent.

A line drawn on chromatography paper with a pencil to mark the starting point for the samples. Pencil is used because ink would also run with the samples.

The movement of a liquid up a narrow tube or porous material, like chromatography paper, due to cohesive forces between the liquid molecules and adhesive forces with the surface.

The degree to which a substance dissolves in a solvent. Substances with higher solubility travel further in paper chromatography.

In paper chromatography, different substances travel at different rates due to varying solubilities, leading to their separation.

Paper chromatography can reveal the different components of a mixture, such as the colors in a black ink.

Crystallisation is the technique used to separate a soluble solid from a solution.

A ratio that represents the distance traveled by a substance in chromatography relative to the distance traveled by the solvent. It's used to identify the components of a mixture.

The Rf value of a substance is always the same for a specific solvent. However, changing the solvent also changes the Rf value.

The Rf value is calculated by dividing the distance traveled by the substance by the distance traveled by the solvent. This gives a ratio with no units, always less than 1.

Rf values help to identify unknown substances by comparing them to known substances run under identical chromatography conditions.

Measure the distance from the baseline to the center of the spot for both the substance and the solvent front.

Because the substance will always travel a shorter distance than the solvent front, leading to a fraction less than 1.

Be careful when measuring distances for Rf calculations in exams. Use a ruler carefully and measure from the baseline to the center of the spot. Marks can be deducted for inaccurate measurements.

A technique that separates substances based on their different affinities for a stationary phase and a mobile phase.

The stationary phase in paper chromatography, a special type of paper that absorbs the solvent and allows the components of the mixture to travel at different rates.

The solvent used in paper chromatography, which travels up the chromatography paper, carrying the components of the mixture with it.

The leading edge of the mobile phase (solvent) on the chromatography paper.

The spots represent the separated components of the mixture. Each spot corresponds to a different substance that has travelled a unique distance based on its affinity for the paper and the solvent.

The line serves as a reference point to measure the distance travelled by the solvent and the separated components.

The Rf value is calculated by dividing the distance travelled by the component (from the base line to the center of the spot) by the distance travelled by the solvent (from the base line to the solvent front).

The Rf value is a characteristic property of a particular substance in a given solvent and on a specific type of chromatography paper, helping to identify the components of the mixture.