Help plz!!!!! have alot of problems to do and dont know how?

Question

How many miles does light travel in 1 microsecond in a vacuum? (The speed of light in a vacuum is 186 000 miles/second.)
A) 0.000 186 miles
B) 0.186 miles
C) 186 miles
D) 1.86 miles

The density of aluminum is 2.70 g/cm3. What is the mass of a cube of aluminum 1.0 cm on each edge?
A) 27.0 g
B) 5.4 g
C) 81 g
D) 2.70 g

If 20 gits equal 1 erb, and 1 futz equals 2 hews, and 10 erbs equal 1 futz, how many gits equals hews?
A) 100 gits
B) 50 gits
C) 500 gits
D) 1000 gits

What are the missing coefficients for the skeleton equation below?
Al2(S04)3(aq) + KOH(aq) ~ Al(OH)3(aq) + K2S04(aq)
A) 2,12,4,6 B) 1,3,2,3 C) 2,3,1,1
D) 1,6,2,3 E) 4,6,2,3

When the equation for the complete combustion of ethanol, C2HSOH, is balanced, what is the coefficient for oxygen?
A)1
B)6
C)3
D)14
E) 7

Use the activity series of metals to write a balanced chemical equation for the following single replacement reaction:
Ag(s) + KN03(aq) ~
A)Ag(s) + KN03(aq) ~ AgN03 + K
B)Ag(s) + KN03(aq) -+ Ag + K + N03
C)Ag(s) + KN03(aq) -+ AgK + N03
D)Ag(s) + KN03(aq) ~ AgKN03
E) No reaction takes place because silver is less reactive than potassium.

Answer 1

1) B.

1 microsecond = 10^-6 sec. Divide accordingly

2) D.

1cm*1cm*1cm = 1cm3
Mass = density x volume
= 2.7g

3) A.

10 erbs = 200 gits
1 hew = 5 erbs = 100gits

4) D.

Balanced equation :
Al2(S04)3(aq) + 3KOH(aq) --> 2Al(OH)3(aq) + 3K2S04(aq)

5) C.

Balanced equation: C2H5OH(aq) + 3O2(g) --> 3H2O(l) + 2CO2(g)

6) A.

Potassium is higher on reactivity series, it WOULD displace Silver to form Potassium metal.

Answer 2

1.
(186000 miles/second) x (1 second/1000000 microseconds)
= 0.186 miles/microsecond

2.
(1.0 cm) x (1.0 cm) x (1.0 cm) = 1.0cm³, so...
(1.0cm³) x (2.70 g/cm³)
= 2.70 grams

3.
20g = 1e, 1f = 2h, and 10e = 1f, so...
10e = 2h (substitute 1f = 2h)
200g = 2h (substitute 1e = 20g)
100g = 1h (divide by 2)
100 gits = 1 hew

4.
First, balance the hydroxides:
Al2(S04)3(aq) + 3KOH(aq) ~ Al(OH)3(aq) + K2S04(aq)
Next, the aluminum:
Al2(S04)3(aq) + 3KOH(aq) ~ 2Al(OH)3(aq) + K2S04(aq)
Hydroxides need to be fixed again:
Al2(S04)3(aq) + 6KOH(aq) ~ 2Al(OH)3(aq) + K2S04(aq)
Balance the sulfates:
Al2(S04)3(aq) + 6KOH(aq) ~ 2Al(OH)3(aq) + 3K2S04(aq)

On each side now there are:
2 aluminum ions
3 sulfate ions
6 potassium ions
6 hydroxide ions
The correct coefficients: 1, 6, 2, 3.

5.
I'm not entirely positive on this one, because I'm not sure if the sulfur is a loner atom at the end of the combustion reaction. In general though, the equation of a combustion is:
______ + O2 = CO2 + H2O.

In this case, I feel the right answer is:
C2HSOH + 2O2 = 2CO2 + H2O + S

But 2 isn't an option. Here's my tip: If you know the correct combustion equation framework for it,
(a) balance the sulfur
(b) balance the carbon
(c) balance the hydrogen
(d) balance the oxygen
For (d), use a fraction in front of the O2 if you have to, then double everything since fractions are not allowed coefficients. It will save you a lot of time.

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Added in answer edit

If this is supposed to be C2H5OH:

C2H5OH + O2 --> CO2 + H2O
C2H5OH + O2 --> 2CO2 + H2O (balance carbon)
C2H5OH + O2 --> 2CO2 + 3H2O (balance hydrogen)
C2H5OH + 3O2 --> 2CO2 + 3H2O (balance oxygen)

Then your answer is 3.
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6.
Sorry, I don't have a chemistry textbook handy. Look at the activity series though. IF silver is more reactive, the equation will be A, I'm fairly sure.


Hope this helps.

Answer 3

well all i got is
1.A
2.D
i THINK 1 is A, but im almost positive 2 is D

Answer 4

#3 is A

The rest, I have NO clue!!

Answer 5

1.B
2.D
3.A
4.D
5.don't know the chemical equation
6.E