Answer:
10.23 grams of sucrose should be added.
Explanation:
1.15 m means molality (moles of solute in 1kg of solvent)
1.15 moles of sucrose are contained in 1 kg of solvent (1000 g)
Let's determine the moles in our mass of solvent.
Firstly we convert the g to kg → 26 g . 1kg/1000g = 0.026 kg
m . mass (kg) = 1.15 mol/kg . 0.026kg → 0.0299 moles.
Finally we convert the moles to mass (mol . molar mass)
0.0299 mol . 342.3 g/mol = 10.23 g
The answer is (2) 2 mol of KI in 500. g of water.. This is a question of colligative properties. Boiling point elevation and freezing point depression depend on the concentration of dissolved solute. You would get the greatest concentration of KI with the largest moles of KI and smallest volume of water.
D) life on earth was seeded by extraterrestrial aliens
3H₂O is formula for 4 molecules of water
When oxygen is found is peroxide, it has an oxidation number of -1.
The chemical formula of hydrogen peroxide is H2O2. We know that hydrogen always has +1 oxidation state until it forms metal hydrides. So in H2O2, the oxidation state ofhydrogen is +1.
Now, let oxidation state of oxygen be x. So,
2 * (+1) + 2*x = 0
2 + 2x = 0
2x = -2
x = -2 / 2
x = -1
Hence, the oxidation number of oxygen in peroxides is -1