Answer:
Explanation:
The essential though process is to ask oneself when converting grams to moles=> 'How many formula weights are in the given mass?' This directs one to divide the substance's formula weight into the given mass (in grams) on order to determine number of moles. That is ...
moles = Given Mass of Substance in grams / formula weight of substance in grams
= 1578 grams / 791 grams-mol.⁻¹ =1.995 mole ≅ 2 moles
To determine whether the amount of H2 in the lab is dangerous, we first need to know how much hydrogen gas is present in the room in units of percent by volume. For this particular problem, we cannot exactly determine since we do not know the total volume of the room. Hope this answers the question.
First, calculate for the amount of heat used up for increasing the temperature of ice.
H = mcpdT
H = (18 g)*(2.09 J/g-K)(50 K) = 1881 J
Then, solve for the heat needed to convert the phase of water.
H = (1 mol)(6.01 kJ/mol) = 6.01 kJ = 6010 J
Then, solve for the heat needed to increase again the temperature of water.
H = (18 g)(4.18 J/gK)(70 k)
H = 5266.8 J
The total value is equal to 13157.8 J
Answer: 13157.8 J