Untitled Flashcards Set

What is a physical change?

A physical change is a transformation that alters the form or appearance of a substance but does not change its chemical composition.

What is a chemical change?

When one or more substances rearrange their particles into a different configuration.

What are some indications of a chemical change?

Shape, temperature, color, light, sound.

What is synthesis in chemical reactions?

A reaction where two or more reactants combine to form a single product (A + B → AB).

Give an example of a synthesis reaction.

Magnesium + oxygen → magnesium oxide.

What is decomposition in chemical reactions?

A reaction where a single compound breaks down into two or more products (AB → A + B).

Give an example of a decomposition reaction.

Water → hydrogen + oxygen.

How does concentration affect reaction rate?

Higher concentration increases the reaction rate.

How does surface area affect reaction rate?

Increased surface area leads to a faster reaction rate.

How does temperature affect reaction rate?

Higher temperatures generally result in faster reaction rates.

What effect does agitation have on reaction rate?

Increased agitation typically speeds up the reaction rate.

What is a catalyst?

A substance that increases the reaction rate without being consumed in the reaction.

What does collision theory state?

Particles must collide with sufficient energy and the correct orientation to react.

What does validity in an experiment assess?

Whether the aim tests and measures what it is intended to.

What does reliability in an experiment require?

Repeating the experiment at least three times and excluding outliers.

What does accuracy in experiments refer to?

The use of precise equipment and obtaining results true to the accepted value.

How should you structure a scientific aim?

Refer to independent and dependent variables.

What axes do line and column graphs usually have?

Dependent variable on the Y-axis and independent variable on the X-axis.

How is hydrogen tested for?

Using the pop test.

How is carbon dioxide tested for?

By observing limewater turning cloudy.

How is oxygen tested for?

By checking if it relights a glowing splint.

What characterizes an exothermic reaction?

It releases energy, usually in the form of heat, causing the surroundings to heat up.

What is noted about energy in reactants and products in an exothermic reaction?

Energy in reactants is higher than in the products.

What is the temperature trend in exothermic reactions?

Temperature increases.

What characterizes an endothermic reaction?

It absorbs energy as heat from its surroundings.

What is noted about energy in reactants and products in an endothermic reaction?

Energy in products is higher than in the reactants.

What is the temperature trend in endothermic reactions?

Temperature decreases.

What is activation energy?

The energy required to initiate a chemical reaction.

What is meant by the term 'outliers' in an experiment?

Results that differ significantly from other observations.

What is the effect of increasing the amount of particles in a reaction?

It increases the likelihood of a reaction occurring.

What happens in a chemical reaction summarized by the collision theory?

Particles must collide with enough energy and in the right orientation.

What does the term 'independent variable' refer to in an experiment?

The variable that is changed or controlled to test its effects.

What does the 'dependent variable' refer to in a scientific context?

The variable that is measured or observed in an experiment.

How is the overall reliability of an experiment ensured?

By consistently obtaining similar results across multiple trials.