Fossils formed when dinosaurs died
Answer: 0.34 mol
Justification:
1) Hepta means 7, so heptahyrate means 7 parts of water. On mole of magnesium sulfate heptadydrate has seven moles of water.
2) The formula of magnesium sulfate heptahydrate is:
Mg SO4 . 7 H2O
3) Calcualte the number of moles of the compound by dividing the mass in grams by the molar mass of formula.
molar mass:
Mg: 24.3 g/mol
S: 32.1 g/mol
O4: 4 * 16.0 g/mol = 64.0 g/mol
H2: 2 * 1.0 g/mol = 2.0 g/mol
O: 16 g/mol
Molar mass = 24.3 g/mol + 32.1 g/mol + 64.0 g/mol + 2.0 g/mol + 16.0 g/mol = 138.4 g/mol
number of moles = mass in grams / molar mass = 6.81 g / 138.4 g/mol = 0.049 mol
4) As stated, there are 7 moles of H2O per each mol of heptahydrate compoind, so the number of moles of water is 7 * 0.049 mol = 0.343 mol
Answer: 0.34 mol
Valence Electron because the more valence electrons an atom can contribute the shared pool, the stronger the metallic bonds will be
The stock solution contains 10.5 moles of HCl per litre. A 5.5 litre solution of 2.5M HCl contains 5.5x2.5 = 13.75moles of HCl. Since every litre of stock solution provides 10.5M HCl, the amount of stock solution needed is 13.75/10.5 = 1.309L. Therefore you would dilute 1.309L of stock solution to 5.5L