<span>We know the relation between heat and temperature follows the formula:
Q = Ce * m * (Tf-Ti) , where Q is heat transfer, Ce is specific heat, m is mass, Tf is final temperature and Ti is initial temperature.
Note that heat value is given in kj so we need to change to joules, then as heat is absorbed the final temperature will increase.
4,689 = 0.385 * 34.2 * (Tf-24)
Tf = 4,689 / (0.385 * 34.2) + 24 =380.12ÂşC</span>
D.The sun does not rotate
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
<span>Mn(HPO4)2 - managanese (II) monohydrogen phosphate ion</span>