chem answers
balanced chemical equations imply which of the following
Numbers of atoms are conserved in chemical change.
the oxidation state of chlorine in ClO- is
+1
oxidation state of iodine in IO3- is
+5
The avg. mass of carbon atoms is 12.011 assuming you were able to pick up only one carbon unit, the chances that you would randomly get one with a mass of 12.011
0%
A 230.0 mL of a 0.275 M solution is left on a hot plate overnight the following morning the solution is 1.29 M. What Volume of solvent has evaporated from the 0.275 M solution
181.0mL
what volume of 18 M sulfuric acid must be used to prepare 2.30 L of 0.145 M H2SO4?
19 mL
a given sample of xenon fluoride compound contains molecules of a single type XeFn, where n is some whole number Given that 8.06x10^20 molecules of XeFn weigh 0.227 calculate n
2
an unknown diprotic acid requires 44.39mL of 0.111 M NaOH to completely neutralize a 0.580-g sample calculate the approximate molar mass of the acid
235g/mol
in which of the following does nitrogen have an oxidation state of +4
NO2
PCl5+H20= POCl3 +HCl, balance
none
how many of the following salts are expected to be insoluble in water
none
when solutions of carbonic acid and copper (II) hydroxide react which of the following are spectator ions?
none
which of the following is a strong acid
HClO4
which if the following salts is insoluble in water?
all soluble
The sum of the total of the representative masses of the products between the masses of the most stable isotopes and the decimal equivalent of the relative abundance is known as the
average atomic mass
in balancing an equation we change the to make the number of atoms on each side of the equation balance
coefficient of compounds
the limiting reactant in a reaction
has the lowest ratio of moles available/coefficient in the balanced equation
the chemical counting in the S.I. is known as the
mole
a component in the minority Is known as
solute
a component of a solution in majority is known as the
solvent
polar molecules have an unequal distribution of charge within the molecules
true
the combined avg atomic masses of one mole of a compound is known as the molar mass of that substance
true
the molecular formula always represents the total number of atoms of each element present in a compound
true
suppose you are given the percent by mass of the elements in a compound and you wish to determine the empircal formula which is true?
you must convert percent by mass to relative numbers of atoms
In the reaction Zn +H2SO4 -> ZnSO4 + H2, which if any element is oxidized?
zinc
molecular formula for aspirin
C9H8O4
given the equation 3A+B = C+ D you react 2 miles of A with 1 mole of B which of the following is true
A is the limiting because you need 3 moles of A and have 2
a hydrocarbon (a compound consisting solely of carbon and hydrogen is found to be 85.6% carbon by mass what's the empircal formula?
CH2
which if the following ions is most likely to form an insoluble sulfate?
Ca^2+
which of the following aqueous solutions contain the greatest number of ions
300.0 ml of 0.10 M CaCl2
what is the mass of 4 atoms of copper in grams?
4.22x10^-22
what mass of NaOH is required to react exactly with 25.0mL of 2.7 M H2SO4
5.4 g
How many grams of NaCl are contained in 350 ml of a 0.287 M solution of sodium chloride
5.87g
Hydrocortisone valerate is an ingredient in hydrocortisone cream, prescribed for skin problems. it's molecular formula is C26H38O6
69.9%
a hypothetical element consists of two isotopes of masses 69.95 Amu and 71.95 amu with abundances of 25.7% and 74.3% respectively what is the avg. atomic mass of this element
71.4
aqueous solutions of sodium sulfide and copper (II) chloride are mixed together. which statement is correct?
CuS will precipitate from solution
Oxidation is the gain of electrons
F
a chemical that changes color at the endpoint of reaction is called a colorimeter
F
which if the following is not a strong base
NH3
a reducing agent is an electron donor
T
the concentration of a salt water solution that sits in an open beaker decreases over time
T
One can always do a direct conversion from Mass of a substance to particles as long as you express your answer to the correct number of sig figs
false
an acid is a substance that produces OH- ions in water
false
the reactant with the highest molar mass is always the limiting reactant
false
when balancing a chemical equation it is generally best to start with the least complicated molecules
false
