Answer:
M = 3.0 mol/L.
Explanation:
- We can calculate the molarity of a solution using the relation:
<em>M = (mass x 1000) / (molar mass x V)</em>
- M is the molarity "number of moles of solute per 1.0 L of the solution.
- mass is the mass of the solute (g) (m = 87.75 g of NaCl).
- molar mass of NaCl = 58.44 g/mol.
- V is the volume of the solution (ml) (V = 500.0 ml).
∴ M = (mass x 1000) / (molar mass x V) = (87.75 g x 1000) / (58.44 g/mol x 500.0 ml) = 3.0 mol/L.
Answer:
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This polarity makes water molecules attracted to each other. The oxygen-hydrogen bond in the alcohol molecule is also polar. But, the carbon hydrogen bonds in the rest of the alcohol molecule are nonpolar. In these bonds, the electrons are shared more or less evenly.
Half-life of a radioactive substance is the time required to reduce the amount of substance to half of its initial amount.
In present case, half-life is material is given as 1000 years and initial amount of material is given as 400 kg
Answer 1) Since, half-life of radio-active substance is 1000 years, therefore after 1st half life, amount of the material will be left to half the initial amount. Hence, amount of substance left after 1000 years = 400/2 = 200 kg.
Answer 2) For 2000 years, radioactive material has crossed 2 times the half life. Therefore , amount of the material will be left to 1/4 the initial amount. Hence, amount of substance left after 2000 years = 400/4 = 100 kg.
Answer 3) For 4000 years, radioactive material has crossed 4 times the half life. Therefore , amount of the material will be left to 1/16 the initial amount. Hence, amount of substance left after 4000 years = 400/16 = 25 kg.
