Chemistry Flashcards
What is mass loss in the context of chemical reactions?
Mass loss occurs when there is a gaseous product formed during a reaction.
This concept is important for understanding changes in mass during reactions involving gas evolution.
Why is the reaction fastest at the beginning?
There are the most reactant particles at the start, leading to the highest frequency of successful collisions.
Initial concentration of reactants plays a critical role in the rate of reaction.
Why does the reaction slow down over time?
As time goes on, there are fewer reactant particles, resulting in less frequent successful collisions.
This decrease in reactant concentration affects the rate of reaction.
What causes a chemical reaction to stop?
The reaction stops when the reactants are exhausted or run out.
Completion of the reactants signifies that no further reaction can occur.
What is the purpose of placing cotton wool in the conical flask during the experiment?
To stop liquid from escaping or spitting from the flask.
This method helps maintain the integrity of the experimental conditions.
What is the rate of reaction?
The speed at which reactants are converted into products in a chemical reaction.
True or False: The rate of reaction can be affected by temperature.
True
Fill in the blank: Increasing the concentration of reactants generally ______ the rate of reaction.
increases
What effect does increasing temperature have on the rate of reaction?
It usually increases the rate of reaction.
What is a catalyst?
A substance that increases the rate of reaction without being consumed in the process.
Which of the following factors does NOT affect the rate of reaction? a) Temperature b) Pressure c) Color d) Surface area
c) Color
True or False: A larger surface area of a solid reactant increases the rate of reaction.
True
What is the collision theory?
A theory that states that for a reaction to occur, reactant particles must collide with sufficient energy and proper orientation.
Fill in the blank: The ______ of a reaction is the change in concentration of a reactant or product per unit time.
rate
What is the role of temperature in the collision theory?
Higher temperatures increase the energy of particles, leading to more frequent and energetic collisions.
True or False: Decreasing the pressure increases the rate of reaction for gases.
False
Define ‘activation energy’.
The minimum energy required for a chemical reaction to occur.
What is the effect of a catalyst on activation energy?
A catalyst lowers the activation energy required for the reaction.
Fill in the blank: The ______ of a reaction can be measured by the amount of product formed over time.
rate
Which factor is likely to increase the rate of reaction between solids?
Increasing the surface area.
True or False: All chemical reactions occur at the same rate.
False
What happens to the rate of reaction as reactants are used up?
The rate of reaction decreases.
Fill in the blank: A reaction that occurs quickly is said to have a ______ rate of reaction.
high
What is an example of a reaction that occurs very slowly?
Rusting of iron.
