Calculate no. Of moles in 329g of H2so4

Nuclear Processes Unit Test

Finger [1]

Answer:

?

Explanation:

8 0

3 years ago

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How many molecules are in 20,484 grams of H2O?

alexandr1967 [171]

Answer:

3.4027x10^-22

Explanation:

4 0

3 years ago

A sample of Manganese (II) chloride has a mass of 19.8 grams before heating, and 12.6 grams after heating until all the water is

IRINA_888 [86]

Answer:

no. of water molecules associated to each molecule of $MnCl_2$ = 4

Explanation:

Mass of $MnCl_2$ before heating = 19.8 g

Mass of $MnCl_2$ after heating = 12.6 g

Difference in mass of $MnCl_2$ before and after heating

= 19.8 - 12.6 = 7.2 g

Difference in mass corresponds to mass of water driven out.

Molar mass of water = 18 g/mol

No. of moles of water = $\frac{7.2}{18} = 0.4\ mol$

Mass of $MnCl_2$ obtained after heating is mass of anhydrous $MnCl_2$ .

Mass of anhydrous $MnCl_2$ = 12.6 g

Molar mass of $MnCl_2$ = 125.9 g/mol

No. of mol of anhydrous $MnCl_2$ = $\frac{125.9}{125.9} = 0.1\ mol$

so,

0.1 mol of $MnCl_2$ have 0.4 mol of water

1 mol of $MnCl_2$ will have = $\frac{0.4}{0.1} =4\ mol$

Hence, no. of water molecules associated to each molecule of $MnCl_2$ = 4

5 0

3 years ago

Calculate the pH of: (a) 0.1M HCl; (b) 0.1M NaOH; (c) 3 X 10% M HNO3; (d) 5 X 10-10 M HCIO.; and (e) 2 x 10-8 M KOH.

Shtirlitz [24]

Answer:

(a) $pH = -Log (0.1M) = 1$

(b) $pH = -Log (10^{-13}M) = 13$

(c) $pH = -Log (3x10^{-3}M) = 2.5$

(d) $pH = -Log (4.93x10^{-10}M) = 9.3$

(e) $pH = -Log (5^{-7}M) = 6.3$

Explanation:

To calculate de pH of an acid solution the formula is:

$pH = -Log ([H^{+}]) = 1$

were [H^{+}] is the concentration of protons of the solution. Therefore it is necessary to know the concentration of the protons for every solution in order to solve the problem.

(a) and (c) are strong acids so they dissociate completely in aqueous solution. Thus, the concentration of the acid is the same as the protons.

(b) and (e) are strong bases so they dissociate completely in aqueous solution too. Thus, the concentration of the base is the same as the oxydriles. But in this case it is necessary to consider the water autoionization to calculate the protons concentration:

$K_{w} =[H^{+} ][OH^{-}]=10^{-14}$

clearing the $[H^{+} ]$

$[H^{+} ]=\frac{10^{-14}}{[OH^{-}]}$

(d) is a weak base so it is necessary to solve the equilibrium first, knowing $Ka=3.24x10^{-8}$

The reaction is $HClO$ → $H^{+} + CO^{-}$ so the equilibrium is

$Ka=3.24x10^{-8}=\frac{x^{2}}{5x10^{-8}-x}$

clearing the x

${x^{2}={1.62x10^{-17}-3.24x10^{-8}x}$

$x=[H^{+}]=4.93x10^{-10}$

6 0

3 years ago

Which liquid has the strongest intermolecular forces? a.chcl3 b.ccl4 c.h2o?

elixir [45]

In a solution of water and ethanol, hydrogen bonding is the strongest intermolecular force between molecules. Hydrogen bonding occurs when the partially negative oxygen end of one of the molecules is attracted to the partially positive hydrogenend of another molecule.

4 0

3 years ago