Answer: C) 0.020 m
Explanation:
Molality of a solution is defined as the number of moles of solute dissolved per kg of the solvent.
where,
n = moles of solute
= weight of solvent in g
Mole fraction of 
is = 
i.e. moles of is present in 1 mole of solution.
Moles of solute 
=
moles of solvent (water) = 1 - = 0.99
weight of solvent =
Molality =
Thus approximate molality of in this solution is 0.020 m
Answer:
Number of moles = 0.92 mol
Explanation:
Given data:
Mass of CaSO₄ = 125 g
Number of moles of CaSO₄ = ?
Solution:
Formula:
Number of moles = mass/ molar mass
Molar mass of CaSO₄:
Molar mass of CaSO₄ = 40 + 32+ 16×4
Molar mass of CaSO₄ = 40 + 32+ 64
Molar mass of CaSO₄ = 136 g/mol
Number of moles:
Number of moles = mass/ molar mass
Number of moles = 125 g/ 136 g/mol
Number of moles = 0.92 mol
Answer:
The physical and chemical properties of the product do not match the properties of the reactant.
Explanation:
Chemical change:
The changes, that occur due to change in the composition of a substance and result in a different compound is known as chemical change.
These changes are irreversible
These changes occur due to chemical reactions
These may not be observed with naked eye
Example:
Combustion of fuel or wood: that oil or wood convert into energy, CO2 and ash in case of wood
Boiling of egg: that change the chemical composition of protein in the egg .
The reaction of Hydrogen and oxygen:
H 2 (g) + O 2 (g) -------------------------------------> 2H 2O (l)
The reaction between sugar and oxygen form a product which is different from the reactant that's why it indicate the occurrence of chemical reaction.
While in case of physical changes just state of matter are changed. Properties remain same.
Answer:
Net ionic equation:
Zn²⁺(aq) + 2OH⁻(aq) → Zn(OH)₂(s)
Explanation:
Chemical equation:
ZnCl₂ + KOH → KCl + Zn(OH)₂
Balanced chemical equation:
ZnCl₂ + 2KOH → 2KCl +Zn(OH)₂
Ionic equation;
Zn²⁺(aq) + 2Cl⁻(aq) + 2K⁺(aq) + 2OH⁻(aq) → 2K⁺(aq) + 2Cl⁻(aq) +Zn(OH)₂(s)
Net ionic equation:
Zn²⁺(aq) + 2OH⁻(aq) → Zn(OH)₂(s)
The K⁺ and Cl⁻ are spectator ions that's why these are not written in net ionic equation. The Zn(OH)₂ can not be splitted into ions because it is present in solid form.
Spectator ions:
These ions are same in both side of chemical reaction. These ions are cancel out. Their presence can not effect the equilibrium of reaction that's why these ions are omitted in net ionic equation.
Answer:
It is a beta decay equation unknown
Explanation:
none
