Your answers for 1 and 3 are correct. The answer for question 2 contains an error in the calculation. Here are the revised solutions:
1. This calculation is correct: 8.75 moles / 6.22L = 1.41 mol/L.
2. First, calculate the moles of NaOH: 428g / (40 g/mol) = 10.7 moles. Then, divide by the volume of the solution: 10.7 moles / 6.4 L = 1.67 mol/L.
3. Your calculation is right: 4.85 moles / 0.75 M = 6.46 L.
4. To find the molarity of sodium hydroxide, first, we need to find the moles of HCl used in the titration.
Moles of HCl = (0.3 mol/dm³) * (22.0 cm³) / (1000 cm³/dm³) = 0.0066 moles
Since the balanced equation indicates one mole of NaOH reacts with one mole of HCl, there must have been 0.0066 moles of NaOH in the 37 cm³ of NaOH solution.
Moles of NaOH / Volume of NaOH solution = Molarity of NaOH
0.0066 moles / (37 cm³ / 1000 cm³/dm³) = 0.1784 mol/dm³ = 0.178 mol/L
To find the concentration of NaOH in g/dm3, multiply the molarity by the molar mass of NaOH:
0.178 mol/L * 40 g/mol = 7.12 g/dm³
1. You have been given a sample of unknown molarity. Calculate the molarity of a solution which has been prepared by dissolving 8.75 moles of sodium chloride in enough water to produce a solution of 6.22l.
2. You have a sample which consists of 428g sodium hydroxide (NaOH) dissolved in enough water to make a final solution of 6.4l. What is the molarity?
3. You have been given a sample of 4.85 moles of glucose (C6H12O6) and you want to make a 0.75M solution with it. What will be the final volume of solution?
4. 37.0cm³ of a sodium hydroxide (NaOH) solution was pipetted into a conical flask and titrated with a standard solution of 0.45 mol dm-3 (0.3M) hydrochloric acid according to the following equation:
NaOH(aq) + HCl(aq) → NaCl(aq) + H2O(l)
A universal indicator solution was used for the titration and it was found that 22.0 cm3 of the acid (HCl) was required to neutralise the alkali (NaOH). Calculate the molarity of the sodium hydroxide and its concentration in g/dm3.
MY ANSWERS:
1. 8.75/6.22 = 875/622 = 1.406752412 = 1.41mol/L = M
2. 428/6.41 = 42800/641 = 66.770670826833... = 66.77mol/L = M
3. 4.85/0.75 = 97/15 = 6.46 = 6.46mol/L = M
QUESTION 4 I HAVE NO CLUE PLEASE PLEASE SOMEBODY HELP ME
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