Answer:
1
Explanation:
there is only one sulphur (S) atoms in the formula for sodium sulphate
½H2(g) + ½I2(g) → HI(g) ΔH = +6.2 kcal/mol
or...
½H2(g) + ½I2(g) + 6,2kcal/mole → HI(g)
________
21.0 kcal/mole + C(s) + 2S(s) → CS2(l)
or...
C(s) + 2S(s) → CS2(l) ΔH = +2,1 kcal/mole
_________
ΔH > 0 ----------->>> ENDOTHERMIC REACTIONS
The 2 in front of 
in 
is <u>Coefficient.</u>
_____________________________
The 
after 
in the same equation is <u>sub </u><u>script</u><u>.</u>
_____________________________
There are two atoms of in 
_____________________________
Answer:
mass= 14kg
Explanation:
density= mass/volume
so that means mass= volume x density
m= 2kg/m³ x 7m³
m= 14 kg
Hope this helps
