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sukhopar [10]
2 years ago
5

The combustion of magnesium creates so much energy so quickly that it is hard to measure its enthalpy directly using a simple ca

lorimeter. However, you will break this reaction down into other intermediate reactions whose enthalpies you can – and will – measure. What broad question are you answering by doing this experiment?
Chemistry
2 answers:
riadik2000 [5.3K]2 years ago
6 0
I believe your answer is: What is the enthalpy of formation of magnesium oxide?
Hope this helps! :)
QveST [7]2 years ago
5 0

Answer:  Enthalpy of the reaction of combustion of magnesium

Explanation: The enthalpy of reaction of combustion of methane is usually determined by the usage of the Hess law .

Hess Law states that regardless of the multiple steps of the reaction, the total enthalpy change is equal to the sum of the enthalpies of all the steps involved.

Thus in order to find out the total change in enthalpy of magnesium oxide , we can break the reaction into several intermediate reactions whose entalpies can be easily determined.

You might be interested in
Picric acid has been used in the leather industry and in etching copper. However, its laboratory use has been restricted because
olchik [2.2K]

Answer:

0.3023 M

Explanation:

Let Picric acid = H_{picric}

So,  H_{picric}     +       H_2}O          ⇄      H_3}O^+     +     Picric^-

The ICE table can be given as:

                          H_{picric}     +       H_2}O          ⇄      H_3}O^+     +     Picric^-

Initial:                0.52                                               0                  0

Change:             - x                                                 + x                 + x

Equilibrium:      0.52 - x                                        + x                 + x

Given that;

acid dissociation constant  (K_a) = 0.42

K_a = \frac{[H_3O^+][Picric^-]}{H_{picric}}

0.42 = \frac{[x][x]}{0.52-x}}

0.42 = \frac{[x]^2}{0.52-x}}

0.42(0.52-x) = x²

0.2184 - 0.42x = x²

x²  + 0.42x - 0.2184 = 0                   -------------------- (quadratic equation)

Using the quadratic formula;

\frac{-b+/-\sqrt{b^2-4ac} }{2a}    ;     ( where +/-  represent ± )

= \frac{-0.42+/-\sqrt{(0.42)^2-4(1)(-0.2184)} }{2*1}

= \frac{-0.42+/-\sqrt {0.1764+0.8736} }{2}

= \frac{-0.42+\sqrt {1.0496} }{2}     OR   \frac{-0.42-\sqrt {1.0496} }{2}

= \frac{-0.42+1.0245}{2}       OR    \frac{-0.42-1.0245}{2}

= \frac{0.6045}{2}                 OR    -\frac{1.4445}{2}

= 0.30225          OR     - 0.72225

So, we go by the +ve integer that says:

x =  0.30225

x = [ H_3}O^+ ] = [   Picric^- ] =  0.3023  M

∴  the value of  [H3O+] for an 0.52 M solution of picric acid  = 0.3023 M     (to 4 decimal places).

6 0
2 years ago
A precipitate of zinc hydroxide can be formed using the reaction below.
worty [1.4K]

Answer:

Option B is correct. KOH is the limiting reagent, and 0.27 mole of Zn(OH)2 precipitate is produced.

Explanation:

Step 1: Data given

Number of moles ZnCl2 = 0.36 moles

Number of moles KOH  = 0.54 moles

Step 2: The balanced equations

ZnCl2(aq) + 2 KOH(aq) → Zn(OH)2(s) + 2 KCl(aq)

For 1 mol ZnCl2 we need 2 moles KOH to produce 1 mol Zn(OH)2 and 2 moles KCl

Step 3: Calculate the limiting reactant.

KOH is the limiting reactant. It will completely be consumed (0.54 moles). ZnCl2 is in excess. There will react 0.54/2 = 0.27 moles

There will remain 0.36 - 0.27 = 0.09 moles.

Step 4: The products

There will be produced 2 moles KCl and 1 mol Zn(OH)2. Zn(OH)2 is the precipitate produced.

For 1 mol ZnCl2 we need 2 moles KOH to produce 1 mol Zn(OH)2 and 2 moles KCl

For 0.54 moles KOH, we will produce 0.27 moles precipitate (Zn(OH)2)

Option A is not correct because 0.27 mol of Zn(OH)2 will precipitate, not 0.54 mol

Option B is correct

Option C is not correct because ZnCl2 is not the limiting reactant, but the excess reactant

Option D is not correct because ZnCl2 is not the limiting reactant, but the excess reactant

7 0
2 years ago
The volume of hcl gas required to react with excess ca to produce 11.4 l of hydrogen gas at 1.62 atm and 62.0 °c is ________ l.
seropon [69]

Answer:

22.8 L  

Step-by-step explanation:

We can use <em>Gay-Lussac's Law of Combining Volumes</em> to solve this problem:

Gases <em>at the same temperature and pressure</em> react in simple whole-number ratios.

1. Write the chemical equation.

Ratio:                 2 L                             1 L

          Ca(s) + 2HCl(g) ⟶ CaCl₂(s) + H₂(g)

V/L:                                                     11.4

2. Calculate the volume of HCl.

According to the law, 2 L of HCl form 1 L of H₂.

Then, the conversion factor is (2 L HCl/1 L H₂).

Volume of HCl = 11.4 L H₂ × (2 L HCl/1 L H₂)

                         = 22.8 L HCl

3 0
2 years ago
Anyway, which is a spectator ion involved in the reaction of k2cro4(aq) and ba(no3)2(aq)?
marissa [1.9K]

Nitrate ions \text{NO}_3^{-} and potassium ions \text{K}^{+}.

<h3>Explanation</h3>

Potassium dichromate undergoes a double-decomposition reaction with barium nitrate to produce barium dichromate and potassium nitrate. The reaction is possible due to the low solubility of barium dichromate that precipitate out of the solution readily after its production.

Start with the balanced chemical equation for this process:

\text{K}_2\text{CrO}_4 \; (aq) + \text{Ba}(\text{NO}_3)_2 \; (aq) \to \text{Ba}(\text{CrO}_4)_2 \; (s) + 2 \; \text{KNO}_3 \; (aq)

Rewrite the chemical equation as an ionic one; express all soluble salts- those with state symbol (aq)- as their constituting ions while leaving the insoluble (s) intact.

2 \; \text{K}^{+}\; (aq)+ 2\; \text{CrO}_4^{-} \; (aq) + \text{Ba}^{2+} \; (aq) + 2 \; \text{NO}_3^{-} \; (aq) \\ \to \text{Ba}(\text{CrO}_4)_2 \; (s) + 2 \; \text{K}^{+} \; (aq) + 2 \; \text{NO}_3^{-} \; (aq)

\text{K}^{+} and \text{CrO}_4^{-} are found on both sides of the equation by the same quantity. The two ions thus took no part in the net reaction and act as spectator ions.

5 0
2 years ago
32. Mercury has an atomic mass of 200.59 amu. Calculate the a. Mass of 3.0 x 1023 atoms. b. Number of atoms in one nanogram of M
Radda [10]

a.200.59 amu of mercury contains = 6.02 * 1023 molecules

Mass for 3.0 * 1023 molecules = (3.0 * 1023 * 200.59) /6.02 * 1023

= 100.29 amu

Thus, mass for 3.0 * 1023 molecules is 100.29 amu

b.As, 200.59 g mercury contains = 6.02 * 1023 atoms

1 g mercury contains = (6.02 * 1023 /200) atoms

= 3.01 * 1021 atoms

Thus, 1 ng mercury contains = (3.01 * 1021) / 109

= 3.01 * 1012 atoms

Thus, 3.0 * 1012 atoms present in 1 ng mercury


6 0
2 years ago
Read 2 more answers
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