Answer:
Factors that cause population growth include increased food production, improved health care services, immigration and high birth rate. These factors have led to overpopulation, which has more negative effects than positive impacts. The world population today is over 7 billion and the number is increasing with each passing year.
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Answer:
Mole fraction for solute = 0.1, or 10%
Molality = 6.24 mol/kg
Explanation:
22.3% by mass → In 100 g of solution, we have 22.3 g of HCOOH
Mass of solution = 100 g
Mass of solute = 22.3 g
Mass of solvent = 100 g - 22.3g = 77.7 g
Let's convert the mass to moles
22.3 g . 1mol/ 46 g = 0.485 moles
77.7 g. 1mol / 18 g = 4.32 moles
Total moles = 4.32 moles + 0.485 moles = 4.805 moles
Xm for solute = 0.485 / 4.805 = 0.100 → 10%
Molality → mol/ kg → we convert the mass of solvent to kg
77.7 g. 1 kg / 1000g = 0.0777 kg
0.485 mol / 0.0777 kg = 6.24 m
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Answer is: the combined ionic bond strength of CrCl₂ and intermolecular forces between water molecules.
When chromium chloride (CrCl₂) is dissolved in water, the temperature of the water increases, heat of the solution is endothermic.
Dissociation of chromium chloride in water: CrCl₂(aq) → Cr²⁺(aq) + 2Cl⁻(aq).
Energy (the lattice energy) is required to pull apart the oppositely charged ions in chromium chloride.
The heat of hydration is liberated energy when the separated ions (in this example chromium cations and chlorine anions) attract polar water molecules.
Because the lattice energy is higher than the heat of the hydration (endothermic reaction), we can conclude that bonds between ions are strong (the electrostatic attraction between oppositely charged ions).
The balanced equation for the above reaction is as follows;
Mg + 2HCl ---> MgCl₂ + H₂
stoichiometry of HCl to MgCl₂ is 2:1
we have been told that Mg is in excess therefore HCl is the limiting reactant
number of HCl moles reacted - 0.100 mol/L x 0.0256 L = 0.00256 mol
according to molar ratio, number of MgCl₂ moles formed - 0.00256/2
Therefore number of MgCl₂ moles formed - 0.00128 mol
mass of MgCl formed - 0.00128 mol x 95.20 g/mol = 0.122 g
