Answer:
there are 0.074 moles in 2.3 grams of phosphorus
Answer: final temperatures will be
a) water 21 C
b) concrete 20.005 C
c) steel 20.008 C
d) mercury 53 C
Explanation:
Change in temp dT = dH / (mass x specific heat)
Specific heat of these materials can be found from many sources:
water = 1 kcal / kg C
concrete = 210 kcal / kg C
steel = 114 kcal / kg C
mercury = 0.03 kcal /kg C
So dT (water) from 1 kcal heat into 1 kg water = 1 kcal / (1 kg x 1 kcal/kg C) = 1 C therefore the final temperature is 20 + 1 = 21 C
But dT (steel) = 1 kcal / (1kg x 114 kcal/kg C) = 0.008 C so the final temperature is 20 + 0.008 = 20.008 C
The results for concrete and mercury are calculated in the same way
Answer:
15.35 g of (NH₄)₃PO₄
Explanation:
First we need to look at the chemical reaction:
3 NH₃ + H₃PO₄ → (NH₄)₃PO₄
Now we calculate the number of moles of ammonia (NH₃):
number of moles = mass / molecular wight
number of moles = 5.24 / 17 = 0.308 moles of NH₃
Now from the chemical reaction we devise the following reasoning:
if 3 moles of NH₃ are produce 1 mole of (NH₄)₃PO₄
then 0.308 moles of NH₃ are produce X moles of (NH₄)₃PO₄
X = (0.308 × 1) / 3 = 0.103 moles of (NH₄)₃PO₄
mass = number of moles × molecular wight
mass = 0.103 × 149 = 15.35 g of (NH₄)₃PO₄
Answer:
mol times or devided by molar volume
