Answer:
Molarity = 0.002 M
Explanation:
Given data:
Mass of calcium chloride = 0.321 g
Volume of water = 1.45 L
Molarity of solution = ?
Solution:
Molarity = number of moles / volume in litter.
We will calculate the number of moles of calcium chloride first.
Number of moles = mass/molar mass
Number of moles = 0.321 g/ 110.98 g/mol
Number of moles = 0.003 mol
Molarity:
Molarity = 0.003 mol / 1.45 L
Molarity = 0.002 M
1.386 g of Mg ribbon combusts to form 2.309 g of oxide product. The mass percent of oxygen in the oxide is 40.0 %.
Let's consider the reaction for the combustion of Mg.
Mg + 1/2 O₂ ⇒ MgO
1.386 g of Mg combusts to form 2.309 g of MgO. We want to determine the mass of oxygen in MgO. According to Lavoisier's law of conservation of mass, matter is not created nor destroyed over the course of a chemical reaction. Then, the mass of Mg in the reactants is equal to the mass of Mg in MgO. The mass of the magnesium oxide is the sum of the masses of magnesium and oxygen. The <u>mass of oxygen in the oxide</u> is:

We can calculate the mass percent of O in MgO using the following expression.

You can learn more about mass percent here: brainly.com/question/14990953
Here we assume that disintegration has occur so the normal t½ formular will not be used
mathematically we..⅛×5600 =700
therefore it is about 700years option A