Chem Fall Final
Which two particle each have a mass approximately equal to one atomic mass unit?
Proton neutron
What is the empirical formula of a compound that is 40% sulfur and 60% oxygen by weight
SO 2
Which element has both metallic and nonmetallic properties?
Si
Which of these reactions is possible?
Sn + H2SO4 ==> SnSO4 + H2
What is the balanced equation for: ___ SnO2 + ___ H2 -------> ___ Sn + ___ H2O?
SnO2 + 2 H2--> Sn + 2H2O
Chlorine boils at 239 K. What is the boiling point of chlorine expressed in degrees Celsius?
-34C
A compound differs from a mixture in that a compound always has
homogeneous composition
What is the correct IUPAC name for H2S?
hydrosulfuric acid
In a chemical reaction, the mass of the products ____.
is equal to the mass of the reactants
When combining with nonmetallic atoms, metallic atoms generally will
lose electrons and form positive ions
An atom of carbon-12 and an atom of carbon-14 differ in
mass number
Which is most likely to form a cation?
metal
An atom is electrically neutral because the
number of protons equals the number of electrons.
Which of these rules never apply in naming acids without oxygen?
ous ending
To determine the formula of a new substance, one of the first steps is to find the ____.
percent composition
the ratio of the actual yield to the theoretical yield
percent yield
Which compound is soluble: potassium sulfate or barium sulfate
potassium sulfate
NaClO is named:
sodium hypochlorite
When a precipitation reaction occurs, the ions that do not form the precipitate
stay dissolved in solution.
Which of the following does NOT form a diatomic molecule in its elemental form?
sulfur
Which expression represents the percent by mass of nitrogen in NH4NO3?
. 28 g N/80 g NHmc046-4.jpgNOmc046-5.jpgmc046-6.jpg 100%
Which of the following measurements is expressed to three significant figures?
.070 mm
How many moles of aluminum are needed to react completely with 1.2 mol of FeO? 2Al(s) + 3FeO(s) → 3Fe(s) + Al203
.8 mol
Calculate the number of moles of Almc153-1.jpgOmc153-2.jpg that are produced when 0.60 mol of Fe is produced in the following reaction.
0.20 mol
What is the net charge on an ion that has 9 protons, 11 neutrons, and 10 electrons?
1-
What is the percent composition of chromium in BaCrO4
1.0 x 103
What is the volume of 80.0 g of ether if the density of ether is 0.70 g/mL?
1.1x10 2
The diameter of a carbon atom is 0.000 000 000 154 m.
1.54x10-12
The equation below shows the decomposition of lead nitrate. How many grams of oxygen are produced when 11.5 g NOmc157-1.jpg is formed?
2.00
What is the total number of atoms represented in the formula CuSO4 . 5H2O?
21
Hydrogen gas can be produced by reacting aluminum with sulfuric acid. How many moles of sulfuric acid are needed to completely react with 15.0 mol of aluminum? 2Al(s) + 3Hmc155-1.jpgSOmc155-2.jpg(aq) → Almc155-3.jpg(SOmc155-4.jpg)mc155-5.jpg(aq) + 3Hmc155-6.jpg(g)
22.5
Iron(III) oxide is formed when iron combines with oxygen in the air. How many grams of Femc158-1.jpgOmc158-2.jpg are formed when 16.7 g of Fe reacts completely with oxygen?
23.9 g
A 100.00-gram sample of naturally occurring boron contains 19.78 grams of boron-10 (atomic mass = 10.01 atomic mass units) and 80.22 grams of boron-11 (atomic mass = 11.01 atomic mass units). Which numerical setup can be used to determine the atomic mass of naturally occurring boron?
(0.1978)(10.01) + (0.8022)(11.01)
Element X has two isotopes. If 72.0% of the element has an isotopic mass of 84.9 atomic mass units, and 28.0% of the element has an isotopic mass of 87.0 atomic mass units, the average atomic mass of element X is numerically equal to
(72.0 × 84.9)/100 + (28.0 × 87.0)/100
When iron rusts in air, iron(III) oxide is produced. How many moles of oxygen react with 2.4 mol of iron in the rusting reaction? 4Fe(s) + 3Omc156-1.jpg(g) → 2Fe2Omc156-2.jpg(s)
1.8 mol
If the temperature changes by 100 K, by how much does it change in C
100C
xpress the product of 2.2 mm and 5.00 mm using the correct number of significant digits
11
Express the sum of 7.68 m and 5.0 m using the correct number of significant digits.
12.7m
How many grams of beryllium are needed to produce 36.0 g of hydrogen? (Assume an excess of water.)
162 g
What is the total number of electrons in an atom of potassium?
19
What is the total number of carbon atoms in ethanoic (acetic) acid, (also known as vinegar), with a molecular formula CH3COOH?
2
Aluminum reacts with sulfuric acid to produce aluminum sulfate and hydrogen gas. How many grams of aluminum sulfate would be formed if 250 g H2SO4 completely reacted with aluminum?
290g
In the reaction 2CO(g) + O2 → 2CO2 what is the ratio of moles of oxygen used to moles of CO2 produced?
2:1
If 1 egg and 1/3 cup of oil are needed for each bag of brownie mix, how many bags of brownie mix do you need if you want to use up all 3 eggs and 1 cup of oil?
3
what is the boiling point in kelvins
373
What is the balanced equation for: __ KOH + __ H3PO4 --> __ K3PO4 + __ H2O
3KOH + H3PO4 --->K3PO4 + 3 H2O
When the numbers 4.2 E2 and 8.4 E 1 are multiplied, the exponent of the result, expressed in proper scientific notation is Selected:
4
What is the total charge of the nucleus of a carbon atom?
6
What is the maximum number of grams of PHmc164-1.jpg that can be formed when 6.2 g of phosphorus reacts with 4.0 g of hydrogen to form PHmc164-2.jpg?
6.8 g
what is the percent by mass of carbon in acetone C3H6O?
62.1%
When glucose is consumed, it reacts with oxygen in the body to produce carbon dioxide, water, and energy. How many grams of carbon dioxide would be produced if 45 g of Cmc159-1.jpgHmc159-2.jpgOmc159-3.jpg completely reacted with oxygen?
66 g
If 60.2 grams of Hg combines completely with 24.0 grams of Br to form a compound, what is the percent composition of Hg in the compound?
71.5%
The total number of atoms in one molecule of the compound K3PO4 is
8
Lead nitrate can be decomposed by heating. What is the percent yield of the decomposition reaction if 9.9 g Pb(NOmc169-1.jpg)mc169-2.jpg are heated to give 5.5 g of PbO?
82
What is the percent composition of carbon, in heptane,
84%
n a particular reaction between copper metal and silver nitrate, 12.7 g Cu produced 38.1 g Ag. What is the percent yield of silver in this reaction? Cu + 2AgNO3
88.2%
According to the solubility rules which one of the following is soluble in water?
BaSO4
Which of the following compounds have the same empirical formula?
C 7 H14 and C10H20
The ratio of carbon atoms to hydrogen atoms to oxygen atoms in a molecule of dicyclohexyl maleate is 4 to 6 to 1. What is its molecular formula if its molar mass is 280 g?
C16 H24 O4
Which of the following is NOT an empirical formula?
C2N2H8
Which of the following sets of empirical formula, molar mass, and molecular formula is correct? Selected:
CH4N,90g,C3H12O2
Question 160 Which of the answers below is an ionic representation of the reaction: Calcium nitrate and sodium sulfide solutions react to form solid calcium sulfide and sodium nitrate solution
Ca2+(aq) + 2NO3-(aq) + 2Na +(aq) + S2-(aq) = CaS(s) + 2Na+(aq) + 2NO3-(aq)This is the correct answer.
In naming acids, what is the first question you should ask yourself?
Does the anion have oxygen?
Which of the following compounds has the highest oxygen content by weight?
H2O
Why doesn't gold tarnish in air?
It is relatively unreactive.
What would be the ionic reaction if aqueous solutions of potassium sulfate and barium acetate were mixed?
K2+2(aq) + SO42-(aq) + Ba2+(aq) + (C2H3O2)2-2(aq) = BaSO4(s) + K2+2(aq) + (C2H3O2)-2(aq)
When two substances react to form products, the reactant which is used up is called the
Limiting reagent
When alpha particles are scattered by thin metal foils which observation indicates a very high percentage of space in atoms? Selected:
Most pass through with little or no deflection
What is the formula of nitrogen triiodide?:
NI3
It is important to be able to recognize the ions in an ionic compound. The name of the ionic compound gives you this information. What are the ions in sodium chloride?
Na+, Cl-
According to the activity series for metals, adding metallic iron to a solution of aluminum chloride should result in
No metal replacement reaction
Which atom contains exactly 15 protons
P-32
Which of the following is NOT true about "yield"?
The actual yield may be different from the theoretical yield because insufficient limiting reagent was u
Which of the following is Not true about empirical and molecular formulas?
The empirical formula of a compound can be triple its molecular formula.
Theoretical Yield
The maximum amount of product that could be formed from given amounts of reactants.
Limiting Reagent
The reactant that determines the amount of a product that can be formed in a reaction
Which of the following is NOT true about limiting and excess reagents?
The reactant that has the smallest given mass is the limiting reagent.
Petroleum is classified chemically as
a mixture
A dis placement reaction can be described as:
a more reactive metal replacing a less reactive metal in its compound
A substance that, when dissolved in water, produces a solution that conducts electric current very efficiently is called
a strong electrolyte
The closeness of a measurement to its true value is a measure of its ____.
accuracy
The amount of product formed when a reaction is carried out in the laboratory
actual yield
Which of the following substances can be decomposed (broken down) by chemical means?
ammonia, NH3
Which compound is soluble: magnesium hydroxide or ammonium hydroxide?
ammonium hydroxide
Which compound is soluble?
ammonium phosphate
A proton has a charge that is opposite the charge of
an electron
What is the name of this acid: HClO3?
chloric acid
The average atomic mass recorded on the periodic table for cobalt is 58.933 u. This indicates that the most abundant isotope of cobalt is
cobalt-59
Which of the following is NOT a reason why actual yield is less than theoretical yield?
conservation of mass
The first step in most stoichiometry problems is to ____.
convert given quantities to moles
The lowest whole number ratio of the elements in a compound is called the
empirical formula
The reactant that is not completely used up in a reaction
excess reagent
How many significant figures are in the measurement 811.40 grams?
five
Which of these elements has physical and chemical properties most similar to silicon (Si)?
germanium (Ge)
A balanced chemical equation has
the same number of each kind of atom on both sides of the equation
When an equation is used to calculate the amount of product that will form during a reaction, then the value obtained is called the ____.
theoretical yield
How many significant figures are in the measurement 40,500 mg?
three
The atomic mass of titanium is 47.88 atomic mass units. The atomic mass represents the
weighted average mass of all the naturally occurring isotopes of TI
