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
Kryger [21]
3 years ago
11

The limiting reactant is the chemical substance that determines the amount of product(s) that can ultimately be formed in a reac

tion. During the reaction, the limiting reactant is completely consumed or used up, and therefore, causes the reaction to stop. The limiting reactant can be identified through stoichiometric calculations. After comparing the results, the reactant that produces the smaller mass of product is identified as the limiting reactant. Determine the excess reactant and calculate the mass of the remaining excess reactant after 20.0 grams of Al and 10.0 grams of O2 react. 4 Al(s) + 3 O2(g) → 2 Al2O3(s) For the calculations in this module, the molar mass of an element will be rounded to the hundredths place (0.01 g).
Chemistry
1 answer:
Tamiku [17]3 years ago
5 0

Answer:

The reactant in excess is Al (s)

The mass of remaining excess reactant is 8.76 g.

Explanation:

This is the reaction:

4 Al(s) + 3 O₂(g) → 2 Al₂O₃(s)

4 moles of solid aluminun reacts with 3 moles of oxygen, to make 2 moles of alumina.

Molar mass Al: 26.98 g/m

Molar mass O₂ : 32.00 g/m

Mass / Molar mass : Moles

20 g Al / 26.98 g/m = 0.741 moles

10 g O₂ / 32.00 g/m =  0.312 moles

Let's find out the limiting reactant and the reactant in excess by rules of three:

4 moles of Al reacts with 3 moles of O₂

0.741 moles of Al reacts with  (0.741 .3)/4 = 0.555 moles

Now we know that are needed 0.555 moles of O₂ to consume all the Al but we only have 0.312 moles of O₂.

The O₂ is the limiting reactant, so the Al is the reactant in excess.

Let's make another rule of three

3 moles of O₂ reacts with 4 moles of Al

0.312 of O₂ reacts with  (0.312  .4)/3 = 0.416

We need 0.416 moles to consume all the O₂ and we have 0.741 moles of Al. There's still Al to consume, that's why the Al is the reactant in excess.

When we use 0.416 moles of 0.741 moles of Al, 0.325 moles are remaining to consume all the Al.

Let's calculate the mass

0.325 moles . 26.98 g/m = 8.76 grams

You might be interested in
Consider the halogenation of ethene, where x is a generic halogen: h2c=ch2(g)+x2(g)→h2xc−ch2x(g) you may want to reference (page
KengaRu [80]
Consider the halogenation of ethene is as follows:
CH₂=CH₂(g) + X₂(g) → H₂CX-CH₂X(g)
We can expect that this reaction occurring by breaking of a C=C bond and forming of two C-X bonds.
When bond break it is endothermic and when bond is formed it is exothermic.
So we can calculate the overall enthalpy change as a sum of the required bonds in the products:
Part a) 
C=C break = +611 kJ
2 C-F formed = (2 * - 552) = -1104 kJ
Δ H = + 611 - 1104 = - 493 kJ

2C-Cl formed = (2 * -339) = - 678 kJ
ΔH = + 611 - 678 = -67 kJ

2 C-Br formed = (2 * -280) = -560 kJ
ΔH = + 611 - 560 = + 51 kJ

2 C-I Formed = (2 * -209) = -418 kJ
ΔH = + 611 - 418 = + 193 kJ

Part b)
As we can see that the highest exothermic bond formed is C-F bond so from bond energies we can found that addition of fluoride is the most exothermic reaction
8 0
3 years ago
A 0.187 M weak acid solution has a pH of 3.99. Find Ka for the acid. Express your answer using two significant figures.
Anna35 [415]

Answer:

5.56 × 10⁻⁸

Explanation:

Step 1: Given data

  • Concentration of the weak acid (Ca): 0.187 M
  • pH of the solution: 3.99

Step 2: Calculate the concentration of H⁺

We will use the following expression.

pH = -log [H⁺]

[H⁺] = antilog -pH = antilog -3.99 = 1.02 × 10⁻⁴ M

Step 3: Calculate the acid dissociation constant (Ka)

We will use the following expression.

Ka = \frac{[H^{+}]^{2} }{Ca} = \frac{(1.02 \times 10^{-4})^{2} }{0.187} = 5.56 \times 10^{-8}

3 0
2 years ago
Define and give 3 examples of psychical properties ​
Katen [24]

Answer:

A physical property is any property that is measurable, whose value describes a state of a physical system.

Explanation:

-color

-density

-volume

3 0
3 years ago
When two aqueous solutions are combined the reaction forms a solid that settles out of solution. What is this solid called?
Rama09 [41]
During the chemical reaction, the solid substance that is insoluble formed during the combination of two aqueous solutions is called a precipitate. The answer is letter C. The precipitation reaction occurs when a salt is formed in the reaction of solutions with salts. 
6 0
3 years ago
The recommended daily allowance (RDA) of the trace metal magnesium is 410 mg/daymg/day for males. Express this quantity in μg/da
Ira Lisetskai [31]

Answer:

410mg/day *\frac{1000 ug}{1 mg}

Recommended daily Amount (RDA) of magnesium is  410,000 μg/day.

Explanation:

There are 1000μg in 1 mg and 1000 mg in 1g

1 mg=1000μg

The Recommended daily Amount (RDA) is 410 mg/day of magnesium. Converting 410 mg/day into μg/day

410mg/day *\frac{1000 ug}{1 mg}

It will become 410,000 μg/day

So Recommended daily Amount (RDA) of magnesium is  410,000 μg/day.

4 0
3 years ago
Other questions:
  • Which atom has the weakest attraction for electrons in a chemical bond? A) a boron atom B) a calcium atom C) a fluorine atom D)
    11·1 answer
  • Classify correct or incorrect.
    14·2 answers
  • If 2.5 moles of nitrogen (N2) react with hydrogen, how many moles of NH3 are produced​
    8·2 answers
  • Which phrase best describes a covalent bond?
    8·1 answer
  • Mixing sand and salt is it a chemical or physical change​
    6·1 answer
  • Which of the following statements best describes why electrons
    5·1 answer
  • 1.(03.02 LC)<br> Which of the following best defines weather? (3 points)
    15·1 answer
  • Tin-126 has a half life of 100,000 years. How many years does it take to
    5·2 answers
  • Does SiO2 also equal Si2O4?<br> (silicon atom 1 oxygen atom 2 = silicon atom 2 oxygen atom 4?)
    5·1 answer
  • 4. When the speed of the following water increases it cuts into the
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!