Answer:
35 amu
Explanation:
In an atom, only masses of protons and neutrons are relevant. electrons are so small in size that their masses are negligible.
The mass of 1 proton/neutron is 1amu.
Mass of SiC = 2 g
<h3>Further explanation</h3>
Given
Reaction
SiO₂(s) + 3C(s) → SiC(s) + 2CO(g)
3.00 g of SiO₂
4.50 g of C
Required
mass of SiC
Solution
mol SiO₂ (MW=60,08 g/mol) :
= 3 g : 60.08 g/mol
= 0.0499
mol C(Ar = 12 g/mol) :
= 4.5 g : 12 g/mol
= 0.375
mol : coefficient of reactants =
SiO₂ : 0.0499/1 = 0.0499
C : 0.375/3 = 0.125
SiO₂ as a limiting reactant(smaller ratio)
Mol SiC based on mol SiO₂ = 0.0499
Mass SiC :
= mol x MW
= 0.0499 x 40,11 g/mol
= 2 g
First, we determine the energy released by the reaction using the heat capacity and change in temperature as such:
Q = cΔT
Q = 32.16 * 0.42
Q = 13.51 kJ
Next, we determine the moles of ammonia formed as the heat of formation is expressed in "per mole".
Moles = mass / molecular weight
Moles = 5/17
Moles = 0.294
Heat of formation = 13.51 / 0.294
The heat of formation of ammonia is 45.95 kJ/mol
In order to obtain solid NaCl, the student should do a few steps.
First, he/she should do filtration. Pass the mixture through a filter paper, where all the sand should be filtered out already because they're not dissolved in the solution plus they're too small to pass through the filter paper.
Next, the filtrate should be left with NaCl (aqueous state). To seperate NaCl with the liquid, the student can either do evaporation or crystallization, depending on how pure or fast he/she wants the results to be. Evaporation involves heating the beaker or whatever apparatus under the bunsen burner until all the liquid has evaporated. Then, some white powder should be left, they're NaCl solid. For crystallization, the student should just put the beaker on a room condition environment, and wait. They might have to wait a month or so for the liquid to completely evaporate itself and left with clear and pure NaCl crystals.
