Science Chapter 9- Test and quizzes
b
For a chemical bond to break, a. individual atoms must be present b. energy is required c. covalent compounds must be mixed d. solids must be dissolved
decomposition reaction
H2CO3 > H2O + CO2 is an example of what type of reaction?
d
How do substances form during a chemical reaction? a. one or more substance are combined b. chemical bonds in molecules add atoms to make more molecules c. a solid substance is formed in a solution d. chemical bonds break, atoms rearrange, and new chemical bonds form
c
How many atoms are represented in the formula CaCO3? a. 3 b. 4 c. 5 d. 6
d
How many oxygen atoms are present in the reactant in this chemical equation? 4 Fe + 3O2 > 2 Fe2O3 a. 2 b. 3 c. 4 d. 6
d
If a chemical symbol in a chemical formula has no subscript, it means a. the chemical symbol is written without any numbers b. the element has no charge c. the chemical is listed last in the formula cl only 1 atom of the element is in the molecule
no
If the chemical properties of a substance have not changed, has a chemical reaction occurred?
4
If you see 4O2 in an equation, what number is the coefficient?
2
If you see 4O2 in an equation, what number is the subscript?
a
In a single-displacement reaction, a. a more reactive element can replace a less reactive element b. only metals and nonmetals can react c. a less reactive element can replace a more reactive element d. most often nonmetals are involved
d
The correct chemical formula for carbon tetrachloride is a. CCl3 b. C3Cl c. CCl d. CCl4
reactants
The first portion of the equation of 2C + 2O2 > 2CO2 is called the ___.
product
The second half of the equation (2CO2) in the equation 2C + 2O2 > 2CO2 is called the ___.
b
The symbol for iron is Fe. The chemical symbol for oxygen is ). The formula for iron oxide, a type of rust, is Fe)3. How many iron atoms are in one molecule of iron oxide? a. 1 b. 2 c. 3 d. 4
a
What causes chemical bonds in molecules to break? a. when molecules bump into each other with enough energy b. when different substances are combined in a solution c. when the temperature of a solution is lowered c. when a solid dissolves in a liquid
a
What is the charge of an ionic compound? a. 0 b. 2 c. 1 d. 4
d
What is the force that holds atoms together called? a. a chemical change b. a chemical reaction c. a chemical bond d. a diatomic molecule
???
What is the name of the compound CB6?
a
What occurs when water freezes? a. a physical change b. a chemical reaction c. a chemical bond d. a diatomic molecule
b
What type of reaction does the following equation represent? FeS + 2HCl > FeCl2 + H2S a. synthesis reaction b. double-displacement reaction c. single-displacement reaction d. decomposition reaction
b
When 2 white compounds are mixed a a solution, a yellow solid forms What kind of reaction has taken place? a. single-displacement reaction b. double-displacement reaction c. decomposition reaction d. physical reaction
synthesis reaction
2Cu + O2 > 2CuO is an example of what type of reaction?
exothermic
2Na + Cl2 > 2NaCl + energy is an example of what type of reaction?
single-displacement reaction
2Na + MgSO4 > Na2SO4 + Mg is an example of what type of reaction?
endothermic
6CO2 + 6H2O + energy > C6H12O6 + 6O2 is an example of what type of reaction?
equation
A chemical ___ describes a chemical reaction.
yield
The arrow sign in the chemical equation 2C + 2O2 > 2CO2 is called the ___ sign.
inhibitor
Adding a ___ will slow down a chemical reaction.
endothermic
An ___ reaction absorbs/needs energy.
exothermic
An ___ reaction gives off energy.
d
An ion is a. a chemical reaction that produces gas and a precipitate b. a chemical reaction that involves nonmetals c. a nonmetal compound with too many electrons d. an atom that gains or loses electrons during a chemical reaction
double-displacement reaction
Ba(CN)2 + H2SO4 > BaSO4 + 2HCN is an example of what type of reaction?
b
Balancing a chemical equation so that the same number of atoms of each element is found in both the reactants and the products is an example of ___. a. activation energy b. the law of conservation of energy c. the law of conservation of mass d. a double-displacement reaction
CaO
Calcium oxide is used to make soil less acidic. What is it's chemical formula?
Al 4, C 6, O 18
Calculate the number of atoms of each element 2Al2(CO)3)3
Na 4, O 4, Cl 4
Calculate the number of atoms of each element 4NaOCl
Ca 1, S 1, O 4
Calculate the number of atoms of each element CaSO4
Fe 1, N 2, O 6
Calculate the number of atoms of each element Fe(NO3)2
chemical
Charcoal is left after a fire. Is this a physical or chemical change?
broken
Chemical bonds are ___ (broken or bonded) during a chemical reaction.
c
Chemical reactions are a. completely different b. exactly the same c. classified by the ways they are alike d. classified by the ways they are different
increase
Does a higher concentration of a solution increase or decrease the rate of reactions?
a
Enzymes in your body act as catalysts, thus the role of enzymes is a. to increase the rate of chemical reactions b. to decrease the rate of chemical reactions. c. to help you breathe d. to inhibit chemical reactions.
a
In which kind of chemical reaction do 2 or more substances combine to form 1 new compound? a. synthesis reaction b. decomposition reaction c. single-displacement reaction d. double-displacement reaction
a
Most chemical reactions a. have starting substances that collide with each other b. do not break bonds c. do not rearrange atoms. d. cannot be see.
gas formation, solid formation, color change, energy change
Name 4 clues that signal that a chemical reaction is taking place.
gas formation, solid formation, energy change, color change
Name 4 possible signs that a chemical change has taken place.
raise the temperature, increase the concentration of a reactant, increase the surface area of a reactant, add a catalyst
Name 4 ways you can change the rate of a chemical reaction.
b
Nitrogen dioxide is a covalent compound. How many oxygen atoms are in a nitrogen dioxide molecule? a. 3 b. 2 c. 1 d. 0
physical
Steam escapes from a teapot. Is this a physical or chemical reaction?
coefficient
The 2 in 2C is the ___.
subscript.
The 2 in CO2 is the ___.
c
Which chemical formula shows an endothermic reaction? a. 4H + O2 > 2H2O b. 2Na + Cl2 > 2NaCl + energy c. 2H2O + energy > 2H2 + O2 d. C + O2 > CO2 + energy
d
Which example shows where a coefficient is used correctly to balance the equation? a. Na + Cl2 > 2NaCl b. Na + 2Cl2 > 2NaCl c. 2Na + Cl2 > 2NaCl2 d. 2Na + Cl2 > 2NaCl
a
Which is the chemical formula for a dinitrogen trioxide molecule? a. N2O3 b. 3N2O c. 2N3O2 d. NO3
d
Which is the product in this chemical formula? N + O2 > NO2 a. N b. O c. O2 d. NO2
c
Which of the following actions is an example of the use of activation energy? a. plugging in an iron b. playing basketball c. holding a lit match to paper d. eating
c
Which of the following describes a chemical change? a. a gas is given off when a liquid boils b. a solid forms when a liquid freezes c. a new substance is formed with different properties d. a solid dissolves in a liquid
d
Which of the following is NOT a sign of a chemical reaction? a. gas formation b. solid formation c. energy change d. state change
d
Which of the following is NOT an example of a chemical reaction? a. milk turning sour b. food being digested c. a match burning d. ice melting
n
Which of the following is an example of a diatomic molecule? a. NaCl b. O2 c. Mg d. CaCl2
d
Which of the following is the correct formula for dinitrogen tetroxide? a. N4O2 b. N2 O2 c. N2O5 d. N2O4
c
Which of the following phrases describes a catalyst? a. slows the rate of a reaction b. increases the energy given off by a reaction c. lowers the activation energy of a reaction d. changes permanently when used in a reaction
c
Which of the following states the law of conservation of mass? a. atoms are rearranged in a chemical reaction, and some join new molecules b. 2 compounds combine to form a new compound with different properties. c. mass cannot be created or destroyed in a chemical reaction d. energy is neither created nor destroyed in a chemical reaction.
b
Which of the following usually increases the rate of a reaction? a. decreasing the concentration of the reactants b. grinding a solid reactant into a powder c. lowering the temperature of the reactants d. raising the temperature of the products
d
Which of the following will NOT increase the rate of a chemical reaction? a. adding a catalyst b. increasing the surface area of a solid reactant c. increasing the concentration of reactants d. adding an inhibitor
a
Which of these uses coefficients correctly to balance this equation? N2 + H2 > NH3 a. N2 + 3H2 > 2NH3 b. 2N2 + 2 H2 > 4NH3 c. N2 + H2 > NH3 d. 3N2 + 4H2 > 6NH3
a
Which states the law of conservation of energy? a. in a chemical reaction, energy is neither created nor destroyed, but can change in form b. energy is needed to break chemical bonds cl light energy is released by some exothermic reactions. d. an exothermic reaction releases energy.
a
Why does the law of conservation of mass dictate that chemical equations be balanced? a. because atoms are never gained or lost in a chemical reaction b. because elements are classified by weight c. because chemical formulas are written from left to right d. because using the wrong chemical symbol causes confusion
precipitate
___ is a solid that is produced as a result of a chemical reaction in solution
reactant
___ is a starting material in a chemical reaction
energy
___ is needed to break chemical bonds in reactants
inhibitor
___ is something that slows a chemical reaction
catalyst
___ is something that speeds up a chemical reaction.
coefficient
___ is the number that is placed in front of a chemical symbol or formula.
chemical reaction
___ is the process by which one or more substances change to produce 1 or more different substances.
activation energy
___ is the smallest amount of energy needed to start a chemical reaction
rate of reaction
___ is the speed at which new particles form in a chemical reaction.
single-displacement reaction
___ is when 1 element replaces another element in a compound
decomposition reaction
___ is when 1 or more compounds break down to form 2 or more substances
double-displacement reaction
___ is when ions from 2 or more compounds exchange places.
synthesis reaction
___ when is 2 or more substances combine to form 1 new compound