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siniylev [52]
3 years ago
10

A sample of 2.0 moles of a metal reacts completely with excess oxygen to form 62.0 g of M2O. What element is represented by the

symbol M?
Chemistry
1 answer:
lana66690 [7]3 years ago
5 0
1) State the chemical reaction

4M + O2 ---> 2M2O

2) State the molar ratios

4 mol M : 1 mol O2 : 2 mol M2O

3) Calculate the number of moles of M2O produced

4 mol M / 2 mol M2O = 2 mol M / x => x = 2 mol M * 2 mol M2O / 4 mol M

=> x = 1 mol M2O

4) Calculate the molar mass of M2O

molar mass = mass in grams / number of moles = 62.0 g / 1 mol = 62.0 g/mol

5) Calculate the atomic mass of M

molar mass of M2O = 2 * atomic mass of M + atomic mass of O =>

62.0 = 2 * atomic mass of M + 16

=> atomic mass of M = [62.0 - 16] / 2 = 23

6) Compare that atomic mass with the atomic masses of the metals in the periodic table.

You will find that 23 is the atomic mass of sodium.

Answer: sodium


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give the chemical composition of the followings : Name Chemical Composition Coal gas Water gas Producer gas Natural gas
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Below.

Explanation:

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What type of reaction is shown below?
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Phosphate buffers are commonly used in biological research. If a small amount of strong acid is added to a buffer solution that
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Answer:

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Explanation:

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Buffers consist of a weak acid (HA) and its conjugate base (A–) or a weak base and its conjugate acid. Weak acids and bases do not completely dissociate in water, and instead exist in solution as an equilibrium of dissociated and undissociated species. When a small quantity of a strong acid is added to a buffer solution, the conjugate base, A-, reacts with the hydrogen ions from the added acid to form the weak acid and a salt thereby removing the extra hydrogen ions from the solution and keeping the pH of the solution fairly constant. On the other hand, if a small quantity of a strong base is added to the buffer solution, the weak acid dissociates further to release hydrogen ions which then react with the hydroxide ions of the added base to form water and the conjugate base.

For example, if a small amount of strong acid is added to a buffer solution that is 0.700 M H3PO4 and 0.700 M KH2PO4, the following reaction is obtained:

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