Answer:
60%
Explanation:
M(NH4NO3) = 2*14 +4*1 +3*16 = 80 g/mol
M(3O) = 3*16 = 48 g/mol
(48/80) *100 % =60% oxygen by mass.
Answer:
The mass of silver is 
Explanation:
Given that,
The volume of the truck is 402 cubic feet or 1.138 x 10⁷ mm.
The density of silver is 10.49 g/mL.
We need to find the mass of silver that will fit in this moving truck. Density equals mass divided by volume. So,

1 gram = 10⁻⁶ Megagram

Hence, the mass of silver is 
(doesn't really matter that it's zinc :) )
It is

, where

(in some books 6.022).
Answer:
The internal energy(ΔE) of a substance is calculated below:
From the first law of thermodynamics;
ΔE=q+w
Explanation:
<u>ΔE=q+w</u>
here;
+q=endothermic reaction
-q=exothermic reaction
+w=work done on the system
-w=work done by the system
Given:
q=+1.62kJ=1620J
w=-874J
To solve:
the internal energy(ΔE)
We know:
ΔE=q+w
<em>according to the problem;</em>
ΔE=q-w
since;
w=-874J (i.e.)work is done by the system.
ΔE=1620-874
ΔE=+746J
Therefore the internal energy is +746J
i.e. the option is "c"(+746J)