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3 years ago

If you start with 0.020 g of Mg, how many moles of H2 will you make if the reaction is complete?

Chemistry

1 answer:

irina [24]3 years ago

6 0

If one starts with 0.020 g of Mg, 0.0008 moles of H2 would be made if the reaction is complete.

Going by the balanced equation of reaction in the image, 1 mole of Mg will produce 1 mole of H2 in a complete reaction.

If 0.020 g of Mg is started with:

mole of Mg = mass/molar mass

= 0.020/24.3

= 0.0008 moles

Since the mole of Mg to H2 is 1:1, thus, 0.0008 moles of H2 will also be made from the reaction.

More on stoichiometry can be found here: brainly.com/question/9743981

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Aspirin (acetylsalicylic acid, C9H8O4) is a weak monoprotic acid. To determine its acid-dissociation constant, a student dissolv

Triss [41]

Answer:

1. $3.57\times 10^{-4}$ was the $K_a$ value calculated by the student.

2. $5.93\times 10^{-4}$ was the $K_b$ of ethylamine value calculated by the student.

Explanation:

The $pH$ value of Aspirin solution = 2.62

$pH=-\log[H^+]$

$[H^+]=10^{-2.62}=0.00240 M$

Moles of s asprin = $\frac{2.00 g}{180 g/mol}=0.01111 mol$

Volume of the solution = 0.600 L

The initial concentration of Aspirin = c = $\frac{0.01111 mol}{0.600 L}=0.0185 M$

$HAs\rightleftharpoons As^-+H^+$

initially

c 0 0

At equilibrium

(c-x) x x

The expression of dissociation constant :

$K_a=\frac{[As^-][H^+]}{[HAs]}$ :

$K_a=\frac{x\times x }{(c-x)}$

$=\frac{0.00240 M\times 0.00240 M}{(0.0185-0.00240 )}$

$K_a=3.57\times 10^{-4}$

$3.57\times 10^{-4}$ was the $K_a$ value calculated by the student.

The $pH$ value of ethylamine = 11.87

$pH+pOH=14$

$pOH=14-11.87=2.13$

$pOH=-\log[OH^-]$

$[OH^-]=10^{-2.13}=0.00741 M$

The initial concentration of ethylamine = c = 0.100 M

$C_2H_5NH_2+H_2O\rightleftharpoons C_2H_5NH_3^{+}+OH^-$

initially

c 0 0

At equilibrium

(c-x) x x

The expression of dissociation constant :

$K_b=\frac{[C_2H_5NH_3^{+}][OH^-]}{[C_2H_5NH_2]}$ :

$K_b=\frac{x\times x}{(c-x)}$

$=\frac{0.00741\times 0.00741}{(0.100-0.00741)}$

$K_b=5.93\times 10^{-4}$

$5.93\times 10^{-4}$ was the $K_b$ of ethylamine value calculated by the student.

3 0

3 years ago

What is the molarity of a solution in which 0.321 g of calcium chloride is dissolved in 1.45 L water?

lana66690 [7]

Answer:

Molarity = 0.002 M

Explanation:

Given data:

Mass of calcium chloride = 0.321 g

Volume of water = 1.45 L

Molarity of solution = ?

Solution:

Molarity = number of moles / volume in litter.

We will calculate the number of moles of calcium chloride first.

Number of moles = mass/molar mass

Number of moles = 0.321 g/ 110.98 g/mol

Number of moles = 0.003 mol

Molarity:

Molarity = 0.003 mol / 1.45 L

Molarity = 0.002 M

7 0

3 years ago

The stops in a chemical reaction means ______ A. Yields or makes B. Difference C. Sum D. Together

Sergeu [11.5K]

The answer will be A.

3 0

3 years ago

What does it mean for a chemical equation to be balanced?

Troyanec [42]

it is c because i did this with my teacher and we are doing about chemical atoms

7 0

3 years ago

34.2 gram of sucrose is dissolved in 180 gram water. Calculate the number of hydrogen and oxygen atoms present in the solution.

Naddika [18.5K]

Explanation:

34.2g of C12H22O11 is dissolved in 180g of H20.

Molar mass of sucrose = 342g/mol

Moles of sucrose = 342 / 34.2 = 10 mol.

Molar mass of water = 18g/mol

Moles of water = 180 / 18 = 10 mol.

For hydrogen atoms, there are 22 * 10 in sucrose and 2 * 10 in water, which gives a total of 240.

For oxygen atoms, there are 11 * 10 in sucrose and 1 * 10 in water, which gives a total of 120.

8 0

3 years ago