Which of the following is a solution?

lakkis [162]

I think it is 3, but I'm not sure

4 0

3 years ago

How many grams of iron metal do you expect to be produced when 325 grams of an 87.5 percent by mass iron (II) nitrate solution r

Debora [2.8K]

Answer: 88.2 g

Solution:

1) Chemical equation:

<span>2Al (s) + 3Fe(NO3)2 (aq) → 3Fe (s) + 2Al(NO3)3 (aq)

2) Theoretical molar ratios

2 mol Al : 3 mol Fe(NO3)2 : 3 mol Fe : 2 mol Al(NO3)3

3) Starting mass of pure iron nitrate

% = (mass of iron nitrate / mass of solution) * 100 = 87.5

=> mass of iron nitrate = 87.5 * mass of solution / 100

mass of solution = 325 g

=> mass of iron nitrate = 87.5 * 325 g / 100 = 284.375 g

4) moles of iron nitrate

moles = mass in grams / molar mass

molar mass of Fe(NO3)2 = 179.85 g/mol

moles = 284.375 g/ 179.85 g/mol = 1.58 moles Fe(NO3)2

5) proportion:

             x                                 3 mol Fe
--------------------------- =     ----------------------
1.58 mol Fe(NO3)2          3 mol Fe(NO3)2

Clear x:

x = 1.58 mol Fe

6) Convert 1.58 mol Fe into grams

mass = number of moles * atomic mass

atomic mass of iron = 55.845 g / mol

mass = 1.58 moles * 55.845 g/mol = 88.24 g

Rounded to 3 significant figures: 88.2 grams of Fe.
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6 0

3 years ago

What is the definition of titration

Setler [38]

A titration is a technique where a solution of known concentration is used to determine the concentration of an unknown solution. Typically, the titrant (the know solution) is added from a buret to a known quantity of the analyte (the unknown solution) until the reaction is complete

6 0

3 years ago

A sample of potassium phosphate octahydrate (K3PO4•8H2O) is heated until 7.93 grams of water are released. How many grams did th

Gekata [30.6K]

The original sample of potassium phosphate octahydrate had a mass of 19.6 grams. When it was heated, it released 7.93 grams of water.

Further Explanation:

For every mole of the compound potassium phosphate octahydrate, there are 8 moles of water of hydration which can be removed from the crystal by heating without altering the chemical composition of the substance.

To determine how much original sample was used, the amount of water released upon heating may be used as well as the mole ratio of the water of hydration with the compound itself following the steps below:

Convert mass of water released to moles.
Use the mole ratio of water of hydration to the compound (8 mol water for every mol of potassium phosphate octahydrate) to get the moles of original sample.
Convert the moles of original sample to grams.

STEP 1: Convert 7.93 g water to moles.

$moles \ of\ H_{2}O \ = 7.93 \ g \ H_{2}O \ (\frac{1 \ mol \ H_{2}O}{18.00 \ g \ H_{2}O})\\\boxed {moles \ of \ H_{2}O \ = 0.4406 \ mol}$

STEP 2: Calculate the moles of original sample using the mole ratio: 1 mol K3PO4 8H2O : 8 mol H2O.

$moles \ of \ K_{3}PO_{4}\ 8H_{2}O \ = 0.4406 \ mol \ H_{2}O \ (\frac{1 \ mol \ K_{3}PO_{4}\ 8H_{2}O \ }{8 \ mol \ H_{2}O})\\\\\boxed {moles \ of \ K_{3}PO_{4}\ 8H_{2}O \ = 0.0551 \ mol}$

STEP 3: Convert the moles of original sample to mass.

$mass \ of \ K_{3}PO_{4}\ 8H_{2}O = 0.0551 \ mol \ K_{3}PO_{4}\ 8H_{2}O \ (\frac{356.3885 \ g}{1 \ mol\ K_{3}PO_{4}\ 8H_{2}O})\\ mass \ of \ K_{3}PO_{4}\ 8H_{2}O \ = 19.637 \ g$