Experimental Chemistry and General Chemistry Concepts

This set of flashcards covers key concepts from experimental chemistry, methods of separation, properties of materials, and chemical bonding.

What apparatus is suitable for measuring volume accurately?

Burettes, pipettes, measuring cylinders, and gas syringes.

What are the drying agents mentioned for collection of gases?

Calcium oxide, concentrated sulfuric acid, and fused calcium chloride.

What is the method used for separating solid-liquid mixtures?

Filtration and crystallization or evaporation.

Which technique is used to purify gases?

Drying agents like concentrated sulfuric acid or calcium oxide.

What separation method uses differences in density?

A separating funnel.

How do you interpret paper chromatograms?

Compare with known samples and use Rf values.

What are Rf values used for in chromatography?

To identify the purity and identity of substances.

What does an Rf value of 1 signify?

The component moves the same distance as the solvent front.

What is sublimation in separation techniques?

The process where solids turn directly into gas without becoming liquid.

What happens during distillation?

Liquid is heated to form vapor, which is then cooled to become liquid again.

What is the significance of measuring purity in substances?

Purity impacts the quality and safety of substances used in everyday life.

What apparatus is used to measure time in chemistry experiments?

A stopwatch.

What is the SI unit of temperature?

Kelvin (K).

How is gas collected dependent on its density?

Denser gases sink while less dense gases float.

What feature of a gas syringe makes it suitable for gas collection?

Accurate measurement of small gas volumes.

What happens to gas in water displacement method?

Gas is collected as water is displaced in the jar.

Why can't calcium oxide be used to dry acidic gases?

It reacts with acids and interferes with drying.

What is simple distillation used for?

To separate a liquid from a solution.

What is crystallization mainly used for?

Separating soluble solids from a solution.

What occurs in fractional distillation?

Separation of liquids with different boiling points.

What does the layer of chromatography represent?

The different components of the mixture.

How is the position of the solvent front calculated in Rf values?

Distance travelled by component divided by distance travelled by solvent.

What indicates a pure substance in chromatography?

A single spot on the chromatogram.

What chemical state represents a gas?

'g' or '(g)'.

How can mixtures be separated?

By physical means such as filtration, distillation, or chromatography.

What kind of substances can be separated using sublimation?

Solids that can convert directly to gas.

What is a characteristic of ionic compounds?

They exist as solids at room temperature due to strong ionic bonds.

Why do non-metals gain electrons?

To achieve stable noble gas configuration.

What are valence electrons?

Electrons in the outermost shell of an atom.

What is the relationship between atomic mass and density in gases?

Lighter gases diffuse faster than heavier gases.

How does temperature affect molecular movement?

Higher temperature increases molecular kinetic energy and movement.

What are isotopes?

Atoms of the same element with different numbers of neutrons.

What is the balancing for a chemical equation?

Equalizing the number of atoms of each element on both sides.

What does a metallic bond involve?

Delocalization of electrons among metal atoms.

How does alloying affect properties of metals?

It can enhance strength, malleability, and resistance to corrosion.

What is an example of a covalent bond?

The bond formed between two non-metals sharing electrons.

What is the main characteristic of giant covalent structures?

They are composed of a large number of atoms covalently bonded in a network.

What is the key feature of macromolecules?

They consist of large repeating units covalently bonded.

What is a burette used for in chemistry?

A burette is a laboratory glassware used to measure and dispense precise volumes of liquid, typically in titrations.

How does a burette measure volume?

A burette measures volume at a specified graduation point known as the 'Decimal Place' (dp) to ensure accuracy.

What is the significance of the spout design in a burette?

The spout of a burette allows for controlled dispensing of liquids, which is crucial for accurate volume measurements during experiments.

Why is a burette preferable over a graduated cylinder for titrations?

A burette provides precise control over the volume of liquid dispensed, which is essential for calculating the concentration of a solution during titrations.

What are the common materials used to make burettes?

Burettes are commonly made from glass or plastic, with glass being the preferred choice for its chemical resistance and clarity.

What is the importance of the meniscus reading in using a burette?

The meniscus is the curved surface of liquid in the burette, and reading the bottom of the meniscus at eye level ensures accurate volume measurement.