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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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Car manufacturers are developing engines that use H₂ as fuel. In Iceland, Sweden, and other parts of Scandinavia, where hydroele
weeeeeb [17]

If the coulombs are supplied at 1.44 V, then 4.766 × 10¹¹ joules are produced.

(a) The reaction is

2H₂O + 2e⁻ → H₂ + 2OH⁻

According to the reaction, 2 moles of electrons flow per mole of reaction,

(b) Given

T = 25°C

Change Celsius into Kelvin

T = 25°C

   = (25 + 273 ) K

   = 298 K

<h3>What is Ideal Gas Law ?</h3>

It is expressed as

PV = nRT

Hence ,

n = \frac{PV}{RT}

   = \frac{(12)(3.5.10^{6} )}{(0.082057)(298)}

   = 1.7176 ×10⁶ mole

Now, From the given reaction we can say that ,1 mole of H₂  is produced by 2 moles of electron

Hence, 1.7176 × 10⁶ mole of H₂ is produced by

= 2 × 1.7176 × 10⁶ moles of  electron

= 3.435 ×10⁶ moles of electron

We know that

charge = moles of electron × F

          =  (3.435 ×10⁶ × 96500) C

           =  3.31 × 10¹¹ C

(c) We know that,

Voltage = \frac{energy}{charge}  =  \frac{J}{C}

1.44 V = \frac{energy}{3.31 . 10^{11} }

Energy = 1.44 V × 3.31 × 10¹¹ C

            =  4.766 × 10¹¹ Joules

Thus from the above conclusion we can say that, coulombs are supplied at 1.44 V, then 4.766 × 10¹¹ joules are produced.

Learn more about Fuel Cell here : brainly.com/question/16612142

#SPJ4

Disclaimer : The question given was incomplete on portal, Here is the complete question.

Question : Car manufacturers are developing engines that use H₂ as fuel. In Iceland, Sweden, and other parts of Scandinavia countries, where hydroelectric plants produce inexpensive electric power, the H₂ can be made industrially by the electrolysis of water.

a) How many moles of electrons flow per mole of reaction ?

b) How many coulombs are needed to produce 3.53X10⁶ L of H₂ gas at   12.0 atm and 25°C.

c) If the coulombs are supplied at 1.44 V, how many joules are produced?

8 0
2 years ago
19. When an atom of iron loses all of its 4s electrons and one of its 3d electrons, what is its charge?
Snowcat [4.5K]
Its charge would be the amount of electrons that are lost in total, which the information is not stated

7 0
3 years ago
A 1.68 g sample of water is injected into a closed evacuated 5.3 liter flask at 65°C. What percent (by mass) of the water will b
Angelina_Jolie [31]

Answer:

50.4 % of the water will be vapor

Explanation:

<u>Step 1:</u> Data given

Mass of water = 1.68 grams

volume of the flask = 5.3 L

Temperature = 65°C

Vapor pressure of water at 65°C = 187.5 mmHg = 0.2467 atm

<u>Step 2:</u> Calculate moles of H2O

p*V=n*R*T

⇒ p = the pressure of water = 0.2467 atm

⇒ V = the volume of the flask = 5.3 L

⇒ n = moles of water

⇒ R = gas constant = 0.08206 L*atm/ K*mol

⇒ T = the temperature = 65°C = 338 Kelvin

n = (p*V)/(R*T)

n = (0.2467 * 5.3) /(0.08206* 338)

n = 0.047 moles

<u>Step 3:</u> Calculate mass of water

Mass of water = moles of water * molar mass of water

Mass of water = 0.047 moles *18.02 g/mol

Mass of water = 0.84694 grams

<u>Step 4:</u> Calculate the percent of water vaporized

% = (0.84694 grams/1.68 grams) *100%

% = 50.4%

50.4 % of the water will be vapor

5 0
3 years ago
Which elements are in the same period?
worty [1.4K]

Answer:

Elements that are in the same period have chemical properties that are not all that similar. Consider the first two members of period 3: sodium (Na) and magnesium (Mg). In reactions, they both tend to lose electrons (after all, they are metals), but sodium loses one electron, while magnesium loses two.

Explanation:

(Hoped this helped! :D)

5 0
3 years ago
Ocean water contains 3.5% NaCl by mass. How many grams of sodium chloride can be obtained from 750 g of seawater
Masteriza [31]

26.25g

Explanation:

Given parameters:

Percentage of NaCl in ocean water = 3.5%

Mass of given seawater = 750g

Unknown:

Mass of NaCl in the seawater = ?

Solution:

  This is a simple percentage problem:

We have been given that ocean water contains 3.5% of NaCl;

 Therefore;

Mass of NaCl in seawater = Percentage of NaCl in ocean water x Mass of seawater

Mass of NaCl in seawater = \frac{3.5}{100} x 750g = 26.25g

Learn more:

Percentage brainly.com/question/2917248

#learnwithBrainly

3 0
3 years ago
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