Science study flashcards ( energy change )

Question 1

How can we classify chemical reaction

Answer 1

according to the energy changes during the chemical reactions

Question 2

What is an exothermic reaction

Answer 2

its a chemical reaction that releases heat energy

Question 3

Are combustion reactions exothermic or endothermic

Answer 3

all combustion reactions are exothermic

Question 4

Do exothermic reactions need heat to start

Answer 4

yes, the substances must first be set on fire, they don’t burn by themselves, but if it continues to burn spontaneously it gives off a large amount of heat

Question 5

What is an endothermic reaction

Answer 5

its a chemical reaction that absorbs heat energy

Question 6

Give an example of an endothermic reaction and explain it

Answer 6

decomposition of calcium carbonate ( limestone )

Question 7

Chemical equation for calcium carbonate

Answer 7

CaCO3 + E - CaO + CO2

Question 8

What is another word for calcium carbonate

Answer 8

limestone

Question 9

What Is a decomposition reaction

Answer 9

involves breaking down bonds where a substance is broken down into two or more new substances

Question 10

Can you give an example of a decomposition reaction

Answer 10

calcium carbonate composes into calcium oxide and carbon dioxide, if heat is removed, the reaction stops and cannot continue spontaneously

Question 11

Is decomposition endothermic or exothermic

Answer 11

endothermic

Question 12

What is the law of the conservation of matter

Answer 12

matter cannot be created or destroyed

Question 13

Give me an example of the conservation of matter

Answer 13

x grams of reactants in the reactants cup, eventually x grams of products will also be formed, products may be present in different phases or compounds, therefore this is why we need to balance equations