MgF2 has a molecular weight of 24+19*2 = 62g. Thus, 31 grams of MgF2 represent .5mol. There are 6.022*10^23 particles per mole. Since MgF2 has three atoms in it, we can find the number of atoms by the following:
(.5 mol)(6.022*10^23 particles/mol)(3 atoms in MgF2) = ...
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The formula unit for magnesium fluoride is MgF2. From the periodic table, add the atomic weight of 1 magnesium atom and 2 fluorine atoms to get to get 62.3018. This means that 1 mole of MgF2 is 62.3018g of MgF2. Now, to find out the mass of 4.78 mol MgF2 X the g/mol so that you will cancel the moles, and keep the grams. 4.78 mol MgF2 X 62.3018g MgF2/1mol MgF2 = 297g MgF2 *The answer 297 is in keeping with significant figures. When you multiply or divide, the answer can have no more than the fewest significant figures in the calculation, which was 4.78, and which has only three significant figures.
.01456 g (6.02 x 1023 atoms) / (39.1 g) = 2.24 x 1020 atoms
340 grams
For this problem, the atomic mass is required. Take the mass in grams and divide it by the atomic mass. Then multiply it by Avogadro's constant, 6.02 × 1023. AuCl3= 303.5 grams5.00 grams AuCl3 / (303.5 grams) × (6.02 × 1023 atoms) = 9.92 × 1021 atoms
6.81 grams copper (1 mole Cu/63.55 grams)(6.022 X 1023/1 mole Cu) = 6.45 X 1022 atoms of copper ----------------------------------------
7.92 grams calcium fluoride (1 mole CaF2/78.08 grams)(6.022 X 1023/1 mole CaF2) = 6.11 X 1022 atoms of calcium fluoride --------------------------------------------------
Theoretically the mass is 62,3018 g.
24.31 grams of magnesium is one mole of magnesium, so that is 6.022 X 1023 atoms of magnesium.
Magnesium (II) fluoride, MgF2 Formula weight: 62.302 grams/moleSee the Related Questions for how to calculated the molecular weight of any molecule!
Let us find Magnesium atoms first. 15 grams magnesium (1 mole Mg/24.31 grams)(6.022 X 10^23/1 mole Mg) = 3.72 X 10^23 atoms magnesium Now take this an drive to grams sodium 3.72 X 10^23 atoms (1 mole Na/6.022 X 10^23)(22.99 grams/1 mole Na) = 14 grams of sodium ----------------------------
The formula unit for magnesium fluoride is MgF2. From the periodic table, add the atomic weight of 1 magnesium atom and 2 fluorine atoms to get to get 62.3018. This means that 1 mole of MgF2 is 62.3018g of MgF2. Now, to find out the mass of 4.78 mol MgF2 X the g/mol so that you will cancel the moles, and keep the grams. 4.78 mol MgF2 X 62.3018g MgF2/1mol MgF2 = 297g MgF2 *The answer 297 is in keeping with significant figures. When you multiply or divide, the answer can have no more than the fewest significant figures in the calculation, which was 4.78, and which has only three significant figures.
For this problem, the atomic mass is required. Take the mass in grams and divide it by the atomic mass. Then multiply it by Avogadro's constant, 6.02 × 1023.10.6 grams Mg / (24.3 grams) × (6.02 × 1023 atoms) = 2.63 × 1023 atoms
how much sodium hydroxide in grams must be added to seawater to precipitate 86.9mg of magnesium present?
1.659 [grams] / 47.998 [grams / mol] * 6.02214179(30)×1023 [molecules / mole] * 3 [atoms / molecule]. A bunch.
3.65 grams of water is equal to .203 moles of H2O. This means there is also .203 moles of H2 present, or .408 grams.
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Molecular mass of magnesium = 24.305 g/mol. 0.478 g/24.305 g/mol = .0197 mols