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3 years ago

Kinetic molecular theory states... (choose all that apply)

Chemistry

1 answer:

liraira [26]3 years ago

6 0

I think it’s B hopefully

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Excess magnesium reacts with 165.0 grams of hydrochloric acid in a single displacement reaction.

JulsSmile [24]

Answer:

The volume of hydrogen gas produced will be approximately 50.7 liters under STP.

Explanation:

Relative atomic mass data from a modern periodic table:

H: 1.008;
Cl: 35.45.

Magnesium is a reactive metal. It reacts with hydrochloric acid to produce

Hydrogen gas $\rm H_2$ , and
Magnesium chloride, which is a salt.

The chemical equation will be something like

$\rm ?\;Mg\;(s) + ?\;HCl \;(aq)\to ?\;H_2 \;(g)+ [\text{Formula of the Salt}]$ ,

where the coefficients and the formula of the salt are to be found.

To determine the number of moles of $\rm H_2$ that will be produced, first find the formula of the salt, magnesium chloride.

Magnesium is a group 2 metal. The oxidation state of magnesium in compounds tends to be +2.

On the other hand, the charge on each chloride ion is -1. Each magnesium ion needs to pair up with two chloride ions for the charge to balance in the salt, magnesium chloride. The formula for the salt will be $\rm MgCl_2$ .

$\rm ?\;Mg\;(s) + ?\;HCl\;(aq) \to ?\;H_2 \;(g)+ ?\;MgCl_2\;(aq)$ .

Balance the equation. $\rm MgCl_2$ contains the largest number of atoms among all species in this reaction. Start by setting its coefficient to 1.

$\rm ?\;Mg\;(s) + ?\;HCl\;(aq) \to ?\;H_2 \;(g)+ {\bf 1\;MgCl_2}\;(aq)$ .

The number of $\rm Mg$ and $\rm Cl$ atoms shall be the same on both sides. Therefore

$\rm {\bf 1\;Mg}\;(s) + {\bf 2\;HCl}\;(aq) \to ?\;H_2 \;(g)+ {1\;\underset{\wedge}{Mg}\underset{\wedge}{Cl_2}}\;(aq)$ .

The number of $\rm H$ atoms shall also conserve. Hence the equation:

$\rm {1\;Mg}\;(s) + {2\;\underset{\wedge}{H}Cl}\;(aq) \to {\bf 1\;H_2 \;(g)}+ {1\;MgCl_2}\;(aq)$ .

How many moles of HCl are available?

$M(\rm HCl) = 1.008 + 35.45 = 36.458\;g\cdot mol^{-1}$ .

$\displaystyle n({\rm HCl}) = \frac{m(\text{HCl})}{M(\text{HCl})} = \rm \frac{165.0\;g}{36.458\;g\cdot mol^{-1}} = 4.52576\;mol$ .

How many moles of Hydrogen gas will be produced?

Refer to the balanced chemical equation, the coefficient in front of $\rm HCl$ is 2 while the coefficient in front of $\rm H_2$ is 1. In other words, it will take two moles of $\rm HCl$ to produce one mole of $\rm H_2$ . $\rm 4.52576\;mol$ of $\rm HCl$ will produce only one half as much $\rm H_2$ .

Alternatively, consider the ratio between the coefficient in front of $\rm H_2$ and $\rm HCl$ is:

$\displaystyle \frac{n(\text{H}_2)}{n(\text{HCl})} = \frac{1}{2}$ .

$\displaystyle n(\text{H}_2) = n(\text{HCl})\cdot \frac{n(\text{H}_2)}{n(\text{HCl})} = \frac{1}{2}\;n(\text{HCl}) = \rm \frac{1}{2}\times 4.52576\;mol = 2.26288\;mol$ .

What will be the volume of that many hydrogen gas?

One mole of an ideal gas occupies a volume of 22.4 liters under STP (where the pressure is 1 atm.) On certain textbook where STP is defined as $\rm 1.00\times 10^{5}\;Pa$ , that volume will be 22.7 liters.

$V(\text{H}_2) = \rm 2.26288\;mol\times 22.4\;L\cdot mol^{-1} = 50.69\; L$ , or

$V(\text{H}_2) = \rm 2.26288\;mol\times 22.7\;L\cdot mol^{-1} = 51.37\; L$ .

The value "165.0 grams" from the question comes with four significant figures. Keep more significant figures than that in calculations. Round the final result to four significant figures.

5 0

3 years ago

How many molecules of Mg3N2 (magnesium nitride) are formed when excess Mg (magnesium)

dybincka [34]

Explanation:

3Mg(s) + N2(g) = Mg3N2(s)

First check that the equation is balanced. In this case, it is.

Assuming that magnesium is the limiting reactant:

First find the molecular weight using the Periodic Table.

We find that the atomic mass of magnesium is approximately

24.3g, so the molecular weight is just 24.3g\mol

2. Next we need the mole to mole ratio. As there are 3

magnesiums for 1 magnesium nitride (shown by the coefficients), the

mole to mole ratio is 1 mol Mg3N2\3 mol Mg.

3. We need the amount of the substance, in grams. Since you have not

stated it in the question, I'll just do 10g AS AN EXAMPLE. Note that

depending on the amount, the LIMITING REAGENT MAY DIFFER.

4. Finally, we need the molecular weight of Mg3N2, which we can easily

calculate to be around 100.9\mol.

5. Putting this all together, we have 10gMg⋅ (mol Mg\24.3gMg)

(1mol Mg3N2\ 3mol Mg) (100.9g Mg3N2\mol Mg3N2)

the units will cancel to leave gMg3N2 (grams of magnesium nitride):

10gMg ⋅ (mol Mg\24.3gMg) (1mol Mg3N2\3mol Mg)

(100.9g Mg3N2\mol Mg3N2)

Doing the calculation yields approximately 13.84g.

Assuming that nitrogen is the limiting reactant:

Similarly, following the above steps but with 10g of nitrogen yields 36.04g

In conclusion, as we produce less amount of Mg3N2 when we assumed that Mg was the limiting reagent, magnesium is the limiting reagent and nitrogen is the excess.

Note: This is in THIS CASE, where we have 10g of both. The answer may vary depending on the amount of each substance.

7 0

2 years ago

Read 2 more answers

The gas in a closed container has a pressure of 3.00 x 10² kPa 30 ° C. What will the pressure be if the temperature is lowered t

Rainbow [258]

Answer: 100kPa

Explanation:

P1 = 3.00 x 10² kPa , P2 =?

T1 = 30°C = 30 +273 = 303k

T2 = —172°C = —172 + 273 = 101k

P1/T1 = P2/T2

3 x 10² / 303 = P2 / 101

P2 = (3 x 10² / 303) x 101

P2 = 100kPa

6 0

3 years ago

Which of the following would not be classified as a mineral?

Setler79 [48]

B. a sugar crystal

Because sugar comes from plants, it is classified as an organic compound, not a mineral.

7 0

3 years ago

Read 2 more answers

Write a chemical equation showing how this is an acid according to the Arrhenius definition. Express your answer as a balanced c

mylen [45]

Answer:

$HC_2H_3O_2_{(aq)}\rightarrow H^+_{(aq)}+C_2H_3O_2^-_{(aq)}$

Explanation:

Arrhenius theory:-

The Arrhenius theory was introduced introduced by Swedish scientist named Svante Arrhenius in 1887.

According to the theory, acids are the substances which dissociate in the aqueous medium to produce electrically charged atoms ( may be molecule). Out of these species furnished, one must be a proton or the hydrogen ion, $H^+$ .

So,

The expression for acid, $HC_2H_3O_2$ is:-

$HC_2H_3O_2_{(aq)}\rightarrow H^+_{(aq)}+C_2H_3O_2^-_{(aq)}$

6 0

3 years ago