Most reasonable answer:
Observations and experimentation
12.5% of strontium-90 would remain in a sample after three half-lives have passed. Half-life automatically means 50% of the original amount would remain.
3.16 X 10^-11 M is the [OH-] concentration when H3O+ = 1.40 *10^-4 M.
Explanation:
data given:
H30+= 1.40 X 10^-4 M\
Henderson Hasslebalch equation to calculate pH=
pH = -log10(H30+)
putting the values in the equation:
pH = -log 10(1.40 X 10^-4 M)
pH = 3.85
pH + pOH =14
pOH = 14 - 3.85
pOH = 10.15
The OH- concentration from the pOH by the equation:
pOH = -log10[OH-]
10.5= -log10[OH-]
[OH-] = 10^-10.5
[OH-] = 3.16 X 10^-11 is the concentration of OH ions when hydronium ion concentration is 1.40 *10^-4 M.
Answer:
RbI<RbBr<RbCl<RbF
Explanation:
As stated in the question, the latice energy depends on the relative size of the ions. When the action size is constant as in the question, the lattice energy now depends on the relative of the anions. The order of increase in ionic sizes among the halide ions is fluoride<Chloride<Bromide<Iodide. This order of increasing size means that the lattice energy will decrease accordingly as shown in the answer.
The molarity of a solution that contains 20.0grams of sodium hydroxide in 200. ml of solution is 2.3 M.
<h3>What is Molarity? </h3>
Molarity is defined as the ratio of number of moles of solute to the volume of the solution.
Molarity = number of moles of solute/ Volume of solution
Given,
given mass of sodium hydroxide= 20 g
Volume of the solution = 200 mL.
Firstly, we will calculate the moles of sodium hydroxide.
<h3>What is Mole? </h3>
Mole is defined as the ratio of given mass of substance to the molar mass of substance.
Mole = given mass/ molar mass
Molar mass of sodium hydroxide = 40 g
Mole = 20/40
= 0.5 mol
Molarity = (0.5/ 200) × 1000 = 2.5M
Thus, we calculated that the molarity of a solution that contains 20.0grams of sodium hydroxide in 200. ml of solution is 2.3 M.
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