Answer:
0.2M NaOh
Explanation:
there are 0.2 mol of NaOH in 8.0 g. (8.0/40) =0.2. Molarity = mol/L = 0.2M.
The masses can be found by substractions:
- Mass of CaSO₄.H2O (hydrate):
16.05 g - 13.56 g = 2.49 g
15.07 g - 13.56 g = 1.51 g
- The mass of water is equal to the difference between the mass of the hydrate and the mass of the anhydrate:
2.49 g - 1.51 g = 0.98 g
- The percent of water is found by the formula:
massWater ÷ massHydrate * 100%
0.98 g ÷ 2.49 g * 100% = 39.36%
- The mole of water is calculated using water's molecular weight (18g/mol):
0.98 g ÷ 18 g/mol = 0.054 mol water
- A similar procedure is made for the mole of salt (CaSO₄ = 136.14 g/mol)
1.51 g ÷ 136.14 g/mol = 0.011 mol CaSO₄
- The ratio of mole of water to mole of anhydrate is:
0.054 mol water / 0.011 mol CaSO₄ = 0.49
In other words the molecular formula for the hydrate salt is CaSO₄·0.5H₂O
The molecular formula for sodium chloride is NaCl. The sum of their atomic weights is (22.99 grams/mole + 35.45 grams/mole) = 58.44 grams/mole
take (17.0 grams)/(58.44 grams/mole), which equals 0.291 moles of NaCl.
Answer:
sorry i'm not a scientist but i think it's C
Explanation:
sorry again if i get it wrong for u :(
