Busy. Please wait.
or

show password
Forgot Password?

Don't have an account?  Sign up 
or

Username is available taken
show password

why


Make sure to remember your password. If you forget it there is no way for StudyStack to send you a reset link. You would need to create a new account.
We do not share your email address with others. It is only used to allow you to reset your password. For details read our Privacy Policy and Terms of Service.


Already a StudyStack user? Log In

Reset Password
Enter the associated with your account, and we'll email you a link to reset your password.
Don't know
Know
remaining cards
Save
0:01
To flip the current card, click it or press the Spacebar key.  To move the current card to one of the three colored boxes, click on the box.  You may also press the UP ARROW key to move the card to the "Know" box, the DOWN ARROW key to move the card to the "Don't know" box, or the RIGHT ARROW key to move the card to the Remaining box.  You may also click on the card displayed in any of the three boxes to bring that card back to the center.

Pass complete!

"Know" box contains:
Time elapsed:
Retries:
restart all cards
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.

  Normal Size     Small Size show me how

Energy in Reactions

GCSE chemistry and combined chemistry

QuestionAnswer
How does the law of conservation of energy apply to chemistry? In all chemical reactions, energy is either transferred to the surroundings or from the surroundings.
What is an exothermic reaction? A reaction where energy is transferred to the surroundings.
Give two examples of exothermic reactions. Combustion, respiration
What happens to the temperature of the surroundings during an exothermic reaction? They increase. The thermometer is included in "the surroundings" so shows the temperature increasing.
What is an endothermic reaction? A reaction where energy is transferred from the surroundings.
Give two examples of endothermic reactions. Thermal decomposition reactions, citric acid and sodium hydrogencarbonate.
What happens to the temperature of the surroundings during an endothermic reaction? They decrease. The thermometer is included in "the surroundings" so shows the temperature decreasing.
State two uses of exothermic reactions Self-heating cans, hand warmers
State two uses of endothermic reactions Some cooling sports injury packs
What are reactants? The substances involved in a chemical reaction
What are products? The substances formed when reactants have a chemical reaction
What is a reaction profile? A diagram which shows whether the reactants have more or less energy than the products.
If the reactants have more energy than the products, what kind of a reaction must have taken place? An exothermic one. The missing energy has been transferred to the surroundings.
If the reactants have less energy than the products, what kind of a reaction must have taken place? An endothermic one. The extra energy has been taken in by the surroundings.
Is breaking bonds endothermic or exothermic? Endothermic. Chemical bonds are strong so require energy to break (like when you have to put energy in to separate magnets from each other)
Is making bonds endothermic or exothermic? Exothermic. Energy is released when chemical bonds are formed (like how two magnets move together when close and generate kinetic energy)
How do we work out the overall energy change of a reaction? Work out the difference between the energy needed to break all the bonds in the reactants and the energy released to form all the bonds in the products.
If more heat energy is released forming bonds than is required for breaking bonds in a reaction what kind of reaction is it? exothermic
If less heat energy is released forming bonds than is required for breaking bonds in a reaction what kind of reaction is it? endothermic
Created by: JBearfield