1.What is the empirical formula of a compound that contains 0.04 mole of sodium, 0.04 mole of sulfur, and 0.06 mole of oxygen?
(A) Na2SO4
(B) Na2SO3
(C) NaSO3
(D) Na2S2O4
(E) Na2S2O3
2.How many milliliters of 0.300 M sodium hydroxide must be added to a 150 mL solution of 0.100 M hydrochloric acid to obtain a solution with a pH of 7.00?
(A) 25 ml
(B) 50 ml
(C) 75 ml
(D) 100 ml
(E) 150 ml
3.Which of the following has the highest first ionization energy?
(A) Na
(B) F
(C) Ne
(D) H2
(E) O2
4. The hybridization on the carbon in ethane, C2H6, is
(A)sp3
(B)sp2
(C)sp
(D)sp3d
(E)sp3d2
5.Which of the following gases is the most dense when all are measured under the same conditions?
(A) H2
(B) O2
(C) Cl2
(D) CO2
(E) NO2
Questions 6-9 refer to the following empirical formulas
(A) AB
(B) AB2
(C) AB3
(D) A2B
(E) A2B3
Which of the above represents the formula for the most common compound of A and B, where A and B represent given pairs of elements or polyatomic ions as indicated below?
6. A = Al and B = F
(A) AB
(B) AB2
(C) AB3
(D) A2B
(E) A2B3
7.A = Na and B = O2
(A) AB
(B) AB2
(C) AB3
(D) A2B
(E) A2B3
8. A = C and B = O
(A) AB
(B) AB2
(C) AB3
(D) A2B
(E) A2B3
9. A = NH4+ and B = (SO4)2-
(A) AB
(B) AB2
(C) AB3
(D) A2B
(E) A2B3
10. Which of the following compounds is a semimetal ?
(A) Na
(B) Be
(C) Cl
(D) As
(E) N
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9 comments:
could you explin #2 and #3?
Number 2
To obtain a solution with ph =7 by mixing NaOH and HCl, the number of moles of NaOH must be equal to the number of moles of HCl according to the reaction
NaOH + HCl = NaCl + H2O
The number of moles
n=c x v , where c is the concentration and v is the volume;
by applying this formula to the values in the problem you obtain the right result.
Number 3
You have to determine the electronic configuration of each element - you will be provided with a periodical table at SAT , so you can look up the atomic numbers - and after that to check which configuration is the most stable; The more stable a configuration is, more energy will be required in order to ionize it, and therefore a higher ionization energy will be obtained.
The ionization energy is the energy required to ionize an atom.
for #2, using n = c x v, we have 0.1 x v = 0.3 x 150 so v should be 450 which is not one of the answer.
Unless there is a misprint so it really is 0.1M HCl and 0.3M NaOH, then you get v = 50, which is the B and the given answer.
Yes, it was a misprint I corrected it, thanks.
where do i find the answers to the test?
Why aren't the answers given?
1 E, 2 B, 3 C, 4 A, 5 C, 6 C, 7 D, 8 B, 9 D, 10 D
here you go had two wrong answers. thought i'd correct that.
6. b - NOT c
9. b - NOT d
when finding the empirical formula, CROSS OVER charges. he brought the charges down. big mistake. :)
Shariq, please explain how in the world 6 is B and 9 is B.
6:
The answer is most definitely C, creating AlF3. Aluminum has a charge of 3+ and Fluorine has a charge of -1.
9.
The answer is most definitely D.
NH4+ has a charge of +1, while sulfate has a charge of -2. Therefore, need 2 ammonium ions for each sulfate ion. Thus,
(NH4)2SO4, and D.
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