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.
</span>

6 0

3 years ago

Solutions of Cu2+ turn blue litmus red because of the equilibrium: Cu(H2O)62+(aq) + H2O(l) ↔ Cu(H2O)5(OH)+(aq) + H3O+(aq) for wh

Elanso [62]

Answer: The pH of 0.10 M $Cu(NO_{3})_{2}(aq)$ is 4.49.

Explanation:

Given: Initial concentration of $Cu(H_{2}O)^{2+}_{6}$ = 0.10 M

$K_{a} = 1.0 \times 10^{-8}$

Let us assume that amount of $Cu(H_{2}O)^{2+}_{6}$ dissociates is x. So, ICE table for dissociation of $Cu(H_{2}O)^{2+}_{6}$ is as follows.

$Cu(H_{2}O)^{2+}_{6} \rightleftharpoons [Cu(H_{2}O)_{5}(OH)]^{+} + H_{3}O^{+}$

Initial: 0.10 M 0 0

Change: -x +x +x

Equilibrium: (0.10 - x) M x x

As the value of $K_{a}$ is very small. So, it is assumed that the compound will dissociate very less. Hence, x << 0.10 M.

And, (0.10 - x) will be approximately equal to 0.10 M.

The expression for $K_{a}$ value is as follows.

$K_{a} = \frac{[Cu(H_{2}O)^{2+}_{6}][H_{3}O^{+}]}{[Cu(H_{2}O)^{2+}_{6}]}\\1.0 \times 10^{-8} = \frac{x \times x}{0.10}\\x = 3.2 \times 10^{-5}$

Hence, $[H_{3}O^{+}] = 3.2 \times 10^{-5}$

Formula to calculate pH is as follows.

$pH = -log [H^{+}]$

Substitute the values into above formula as follows.

$pH = -log [H^{+}]\\= - log (3.2 \times 10^{-5})\\= 4.49$

Thus, we can conclude that the pH of 0.10 M $Cu(NO_{3})_{2}(aq)$ is 4.49.

8 0

3 years ago

What is used to represent a bond in an ionic compound ?

Pie

Answer:

Electronegativity difference between 2 atoms

Explanation:

1. If the electronegativity difference (usually called ΔEN) is less than 0.5, then the bond is nonpolar covalent.

2. If the ΔEN is between 0.5 and 1.6, the bond is considered polar covalent

3. If the ΔEN is greater than 2.0, then the bond is ionic.

6 0

3 years ago

Why does hot tea brew faster than cold tea? Provide scientific data.

Ksivusya [100]

Answer:

Increased heat makes all the molecules in the tea/water mix vibrate and move around a great deal more, thus increasing the rate of diffusion, and therefore increasing the rate of brewing.

Explanation:

hope i help lol :)

5 0

3 years ago