Chemistry is the study of ________________ and how it changes
matter
100
A chemical equation that shows the same number of each kind of atom on both sides of the equation is said to be ________________.
balanced
100
Is this equation balanced: Hv2Ov2 ---> Hv2O + Ov2
no (there are 2 O on the left and 3 O on the right)
100
The best way to put out a small kitchen fire is to _____________________
cover it or use a home fire extingisher
100
In the burning of gasoline, all of the following are true EXCEPT:
a) chemical bonds are broken and others are formed (b) the reaction is a physical change (c) new substances are produced (d) energy is released
(b) - it is a chemical change, not a physical one
200
Anything that has mass and takes up space is considered __________________.
matter
200
What happens when chemical bonds break and new bonds form? (a) a physical change (b) a chemical reaction (c) matter is destroyed (d) surface area increases
(b) a chemical reaction
200
Is this equation balanced? 2Fev2Ov3 + 3 C ---> 4Fe + 3COv2
yes
200
A chemical reaction that absorbs energy IN THE FORM OF HEAT is described as ________________
Combustion
200
The number placed below an element's symbol in a chemical formula is called a
subscript
300
The only SURE evidence for a chemical reaction is ____________________
The production of one or more new substances
300
CaCOv3 (the three is a subscript of the CO) represents a chemical _____________
formula
300
Is this equation balanced? SOv2 + Ov2 + 2Hv2O --> 4Hv2SOv4
No. There is only one Sulfur on the left and 4 on the right. There are 4 Hydrogen on the left and 8 Hydrogen on the right
300
A material used to decrease the rate of a chemical reaction is a(n) _________________
inhibitor
300
The flame of a candle gives off black smoke. Does this statement describe evidence for a physical change or a chemical change?
Chemical change- the black smoke is evidence of the formation of a new substance, which means a chemical change occurred
400
The minimum amount of energy that has to be added to start a reaction is the _________________ energy.
activation
400
A shorter, easier way to show chemical reactions, using symbols instead of words, is called a ______________
chemical equation
400
Is this equation balanced? 2Mg + HCl --> MgClv2 + Hv2
No. There are two Magnesium on the left and only one on the right. There is one Hydrogen on the left and two on the right. There is one Chlorine on the left and two on the right.
400
In what way can a fire be brought under control? (a) add fuel (b) add oxygen (c) Remove oxygen (d) remove carbon dioxide
Remove oxygen (or remove heat or remove fuel)
400
Name two of the most common causes of home fires? (there are more)
heaters, faulty electrical wiring, carelessness with cigarettes, kitchen fires started during cooking
500
What is a synthesis reaction?
a reaction produced when simpler substances combine to make a more complex substance.
500
The substances listed on the left side of a chemical equation are the _______________
reactants
500
A bottle of hydrogen peroxide that eventually turns into a bottle of water and oxygen gas is an example of a ________________ reaction (synthesis, decomposition, replacement, precipitate)
decomposition
500
What is the best form of fire safety?
prevention
500
In terms of the fire triangle, explain why fire is effective in fighting fires.
Water covers the fuel so that oxygen cannot reach it and cools the fire so that there is not enough heat for fuel to continue to ignite.