Answer:
A. 85.6 g
= 0.0856 kg.
B. 0.00027 mol/g
= 0.27 mol/kg.
C. 8.39 %
Explanation:
Given:
Molar concentration = 0.25 M
Molar weight of sucrose = 342.296 g/mol
Density of solution = 1.02 g/mL
Mass of water = 934.4 g.
Density in g/l = 1.020 g/ml * 1000ml/1 l
= 1020 g/l
Mass of solution in 1 l of solution = 1020 g
Mass of solution = mass of solvent + mass of solute
Mass of sucrose = 1020 - 934.4
= 85.6 g of sucrose in 1 l of solution.
A.
Density of sucrose = mass/volume
= molar mass/molar concentration
= 342.296 * 0.25
= 85.6 g/l
Number of moles = mass/molar mass
= 85.6/342.296
= 0.25 mol
B.
Molality = number of moles of solute/mass of solvent
= 0.25/934.4
= 0.00027 mol/g
C.
% mass of sucrose = mass of sucrose/total mass of solution * 100
= 85.6/1020 * 100
= 8.39 %
Answer:
1. c. group 15
2. a. group 1
3. c. m
Explanation:
1. and 2. you just have to know the charge rules.
3. m = mass number = total protons and neutrons
- Hope that helped! Please let me know if you need further explanation.
Answer:
Because of the existence of isotopes.
Answer:
No
Explanation:
A white dwarf has a higher surface temperature than a red giant.
Answer is: enthalpy is -1276,8 kJ.
Chemical reaction: 2CH₃OH(l) + 3O₂(g) → 2CO₂(g) + 4H₂<span>O(g).
</span>ΔH(CH₃OH) = -238,7 kJ/mol.
ΔH(H₂O) = -241,8 kJ/mol.
ΔH(CO₂) = -<span>393,5 kJ/mol.
</span>ΔH(O₂) = 0 kJ/mol.
ΔHreaction = ∑ΔHproducts - ∑ΔHreactants
ΔHreaction = (2·(-393,5) + 4·(-241,8) - (2·(-238,7))
ΔH = (-787 - 967,2) + 477,4
ΔH = -1276,8 kJ.