Can someone please help me with chemistry?

Question

Thanks, I have some hw problems that I wasnt sure the anwer of, if u can explain it, that would help and if not its ok!

1. Choose the word that best completes the following statement. In a neutralization reaction an acid and base react to form water and ________________.

a.salt
b.metal
c.ionic compound
d.ester

2.Determine the mass of sodium chloride produced when 1.75 moles of chlorine gas reacts with sodium
a.202.64 g NaCl
b.204.54 g NaCl
c.188.53 g NaCl
d.244.02 g NaCl
e. 2.04 g NaCl

3.The [H+] of a solution is 1 x 10-4. What is the pH of the solution?
a.pH 10
b.pH 8
c.pH 4
d.pH 2

4. There are two answer choices that would correctly complete this sentence. Choose both answers. Antacids are bases. People use the antacids to __________________ the acids in the stomach.
a.buffer
b.increase the concentration of
c.neutralize
d.decrease the concentration of

5. Fe + 2 AgNo3 -> Fe(NO3)2 +2Ag
In the above equation, 4 moles of silver nitrate would produce how many moles of ferrous nitrate.
a.3 moles
b.4 moles
c.1 mole
d.2 moles

6.
7. A chemical reaction in which the products can regenerate the original reactants is a
a.forward reaction.
b.reaction rate.
c.reversible reaction.

8.Which conversion factor below would be used to change liters of oxygen gas to moles of oxygen gas?
a. 22.4 mol gas = 1 L
b. 22.4 L = 1 mol gas
c. 6.02 x 1023 mol gas = 1 L
d. 6.02 x 1023 L = 1 mol gas
9.
10. A basketball with a volume of 3.50 Liters is left in a car when the temperature is 298 K. What will the volume of the ball be as the car heats up to 305 K during the day?
a.3.58L
b.3.85 x 10-5L
c.2.60 x 104L
d.0.292L

11.A solution with a pH of 4 is 1,000 times more acidic than a solution with a pH of 6.
a. False
b. True
12.
13. Oxygen, in all its compounds except peroxides, has an oxidation number of -1.
T/F

14. An increase in the OH- in a solution would result in
a.an increase in alkalinity (baseness).
b.an increase in acidity.
c.a pH of 7.
d.a decrease in pH.

15.The acid formed when hydrogen iodide dissociates in an aqueous solution would be named
a.hydrogen iodic acid.
b.hydroiodic acid.
c.hydrogen iodide acid.
d.iodic acid.

16. When doing a stoichiometry problem, all of the following could be used to solve the problem except
a.conversion equalities
b.mole ratios
c.temperature
d.molar masses
17.
18. A diver goes down to a depth of 132 feet. How many atmospheres of pressure are on the diver?
a.3
b.4
c.5
d.6

19. When balancing a chemical equation, you must insert_____.
a. subscripts to balance chemical formulas
b.coefficients to correct for the conservation of mass
c.subscripts to make all atoms equal to the same number
d.coefficients to correct the oxidation numbers of the elements

opps i forgot a couple, and thank you for helping if you are down here!

20.5,400 moles of P4O10 has a mass of:
a. 52.57 g.
b. 1599982 g.
c.106965425 g.
d.1532412 g.
and i forgot a couple..

9. On a molecular level, how does decreasing the temperature affect the rate of a reaction?
a. Molecular speed increases, and more effective collisions will take place. The reaction will be faster.

b. Molecular speed increases, and fewer effective collisions will take place. The reaction will be slower.

c.Molecular speed slows, and fewer effective collisions will take place. The reaction will be slower.

d.Molecular speed slows, and more effective collisions will take place. The reaction will be faster.

13. Oxygen, in all its compounds except peroxides, has an oxidation number of -1.
True / False

Thank you again!!!

Answer 1

1) salt -- but here's a technicality - a salt is an ionic compound, so both A and C are correct. Be sure to catch your teacher on this one!!

2) first balance your equation
Cl2 + 2 Na ---> 2 NaCl
now use stoichiometry to determine the mass NaCl produced when 1.75 mol Cl2 reacts:
1.75 mol Cl2 x 2 mol NaCl / 1 mol Cl2 = mol NaCl produced
answer from above x mass NaCl = mass NaCl produced
(1.75 x 2/1) (58.5 g) = 204.75 g NaCl
letter "B" is the closest answer.

3) pH = -log[H+]
log[H+] = log (1 x 10^-4) = -4 take negative of -4 to get +4
letter "C"

4) both "C" and "D"

5) The correct answer is 2 moles letter "D" There is a 1 : 2 ratio of Fe to Ag in the equation, so you need 2 Fe to 4 Ag.

6) Letter "C" reversible reactions can go both forward and in reverse.

8) Letter "B" is the molar gas volume. At STP one mole of any gas occupies 22.4 L of volulme. It does not matter what gas it is or the chemical formula. CH4, O2, CO2, Ne all occupy 22.4 L at STP.

9) Letter "C" as the molecular rate slows, the molecules slow down. They have fewer collisions with enough energy for the reaction to occur.

10) Letter "A", the pressure will increase when the temperature increases. This pressure will cause the ball to stretch a bit so the volume increases. It is Charles' Law: V1/T1 = V2/T2

11) False, each increase of 1 in the pH is a power of 10^1. An increase of 2 would be an increase of 10^2, or 100 times the strength.

13) False. Oxygen has an oxidation number of 2- in all compounds except peroxides (O2 2-) where the oxidation number is 1-.

14) Letter "A" is correct. The higher the concentration of OH- ions, the more basic - alkaline - the solution will be. The more basic the solution, the higher the pH.

15) Letter "B" is correct. HI is a binary acid and must begin with "hydro" and end with "ic" having the root of the nonmetal in the middle. HCl = hydrochloric acid, HBr = hydrobromic acid.

16) Letter "C". The temperature does not enter into stoich.

18) The answer is 4 times atmopheric pressure at 132 ft depth. Fresh water doubles the pressure at 33 ft and salt water doubles the pressure at 34 ft.

19) Letter "B". You must never try to change the subscripts of a chemical formula to balance it!! This is a common mistake for first year chemistry students. The coefficients in front of the chemical formula tell how many molecules of that compound are needed to satisfy the law of conservation of mass.

20) multiply 5,400 moles by the mass of P4O10
(mass of P x 4) + (mass of O x 10) = molecular mass

Answer 2

1. a) salt

For example:

NaOH + HCl ----> NaCl + H2O
An base and an acid make a salt and water.

2. b) 204.54g

This is assuming that there is excess sodium present, because you didn't state an amount.

2 Na + Cl2 ----> 2NaCl

If you have 1.75 moles of Cl2, you have twice as many moles of NaCl, so you would have 3.5 moles NaCl. Multiply by the formula mass for sodium chloride and you get 204.54g

3. c) pH 4
Use the formula pH= -log[H+] You put in 1*10^-4 in for H+ and you end up with a pH of 4

4.) c & d

If the stomach has acids, bases will neutralize the acid, and in turn reduce the concentration of acid present.

Hope that helps! Sorry if I made any mistakes!

Answer 3

5 d
7 c
8b
9 c
10 a
11 false 100x
13 true
14 a
15 b
16 c
18 not sure but I think it is 5
19 b
20 b

1-4 were answered correctly by the previous poster, so I chose not to repeat them.

Answer 4

If you spent as much time thinking about the questions and/or actually studying them as you have spent typing them in here, you wouldn't need our help.

Quit waiting until the last minute to do your homework!

Answer 5

Very interesting.