1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
VMariaS [17]
3 years ago
13

14.7 grams of magnesium reacts completely with 9.7 grams of oxygen to form magnesium oxide (MgO). What is the percent compositio

n of the magnesium oxide?
Chemistry
1 answer:
swat323 years ago
5 0
The answer is 60.3% magnesium, 39.7% oxygen.
Solution:
The chemical equation for the reaction is 2 Mg + O2 → 2 MgO.
Since magnesium reacts completely with oxygen, it is the limiting reactant in the reaction. Hence, we can use the number of moles of magnesium to get the mass of MgO produced:
     moles of magnesium = 14.7g / 24.305g mol-1
                                       = 0.6048 mol

     mass of MgO = 0.6048mol Mg(2 mol MgO/2mol Mg)(40.3044g MgO/1 mol MgO) 
                           = 24.376g MgO

We can now solve for the percentage of magnesium:
     % Mg = (14.7g Mg / 24.376g MgO)*100% = 60.3%

We also use the number of moles of magnesium to get the mass of oxygen consumed in the reaction:
     mass of O2 =  0.6048 mol Mg (1mol O2 / 2mol Mg) (31.998g / 1mol O2) 
                        = 9.676g

The percentage of oxygen is therefore
     % O2 = (9.676g O2 / 24.376g MgO)*100%
               = 39.7%
Notice that we can just subtract the magnesium's percentage from 100% to get 
     % O2 = 100% - 60.3% = 39.7%
You might be interested in
1. Identify each of the following changes as endothermic, exothermic, or not possible to tell. The matter to keep in perspective
goldenfox [79]

Answer:

When effervescent antacid tablets are dropped into water, the tablets slowly disappear and the water becomes fizzy- endothermic

On a hot day, water vapor condenses out of the air and turns into liquid droplets on the outside of a cold glass of lemonade- exothermic

The copper on the Statue of Liberty oxidizes and turns blue.- endothermic

Explanation:

An exothermic reaction is a reaction in which heat is given out to the surrounding. The temperature of the system increases when an exothermic reaction occurs. An endothermic reaction occurs when heat is absorbed and the temperature of the system decreases. Oxidation of elements and effervescence of antacid solution are endothermic processes.

Given that the water vapour in air losses energy upon condensation to liquid, the process is exothermic

7 0
3 years ago
How many significant figures are in the following measurement: 68.99 mL
Tanzania [10]

Answer:

Count how many significant figures are in a number, and find which digits are significant. You can use this calculator for significant figures practice: Test your ability to find how many significant figures are in a number.Enter whole numbers, real numbers, scientific notation or e notation. Example inputs are, 3500, 35.0056, 3.5 x 10^3 and 3.5e3.

Explanation:

3 0
3 years ago
Find the molar masses of the following compounds
Hitman42 [59]
1. 134
2. 283
3. 58.3
4. 212
5. 149
6. 180
7. 400
8. 100
9. 127
10. 77
5 0
3 years ago
A total of 2.00 mol of a compound is allowed to react with water in a foam coffee cup and the reaction produces 107 g of solutio
AveGali [126]

Explanation:

The given data is as follows.

             mass (m) = 107 g,      

    \Delta T = (24.70 - 21.00)^{o}C = 3.7^{o}C

       Specific heat of water = 4.18 J/g^{o}C

Since, the relation between heat energy, mass and temperature change is as follows.

                     q = mC \Delta T

Hence, putting the given values into the above formula to calculate the heat energy as follows.

                     q = mC \Delta T

                        = 107 g \times 4.18 J/g^{o}C \times 3.7^{o}C

                        = 1654.86 J

Therefore, calculate the enthalpy of this reaction for 2.00 mol of a compound as follows.

                     \frac{1654.86 J}{2.00 mol}              

                  = 827.43 J/mol

or,               = 827.43 \times \frac{1 kJ}{1000 J}       (as 1 kJ = 1000 J)

                  = 0.827 kJ/mol

Therefore, we can conclude that enthalpy of this reaction is 0.827 kJ/mol.

4 0
3 years ago
A saline solution contains 1.1% NaCl by mass. How much NaCl is present in 96.3 g of this solution
timurjin [86]

Answer:

= 1.0593 g

Explanation:

1.1% NaCl by mass, means;

1.1 g per 100 g = 0.011

Therefore; the amount of NaCl present in 93.6 g of the solution is;

= 0.011 × 96.3 g

<u>= 1.0593 g</u>

8 0
4 years ago
Other questions:
  • Newtons second law of motion states that
    5·1 answer
  • Gas molecules colliding with the walls of a container exert a force called ___
    14·1 answer
  • Why do we use scientific notation or scientific exponential numbers in math calculations?
    8·1 answer
  • Which of the following is a compound? A. Sn B. CO C. H D. Mg
    9·1 answer
  • Write a balanced net ionic equation for the following reaction. Explain how you arrived at this answer. What did you cancel out?
    9·1 answer
  • Carbon hexafluroide formula
    13·1 answer
  • What happens to frequency as wavelength
    13·1 answer
  • How much force is needed to accelerate a 1,000kg car at a rate of 8m/s2
    8·2 answers
  • What has the lowest ionization erergy?
    5·1 answer
  • Why does liquid move like it does when heated in the middle?
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!