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
slavikrds [6]
2 years ago
12

Câu 47: Cách pha chế dung dịch từ hoá chất tinh khiết, phát biểu sai:

Chemistry
1 answer:
VashaNatasha [74]2 years ago
6 0

Answer:

a

Explanation:

You might be interested in
During a combustion reaction, 9.00 grams of oxygen reacted with 3.00 grams of CH4.
Monica [59]

Answer:

0.74 grams of methane

Explanation:

The balanced equation of the combustion reaction of methane with oxygen is:

  • CH₄ + 2 O₂ → CO₂ + 2 H₂O

it is clear that 1 mol of CH₄ reacts with 2 mol of O₂.

firstly, we need to calculate the number of moles of both

for CH₄:

number of moles = mass / molar mass = (3.00 g) /  (16.00 g/mol) = 0.1875 mol.

for O₂:

number of moles = mass / molar mass = (9.00 g) /  (32.00 g/mol) = 0.2812 mol.

  • it is clear that O₂ is the limiting reactant and methane will leftover.

using cross multiplication

1 mol of  CH₄ needs → 2 mol of O₂

???  mol of  CH₄  needs → 0.2812 mol of O₂

∴ the number of mol of CH₄ needed = (0.2812 * 1) / 2 = 0.1406 mol

so 0.14 mol will react and the remaining CH₄

mol of CH₄ left over = 0.1875 -0.1406 = 0.0469 mol

now we convert moles into grams

mass of CH₄ left over = no. of mol of CH₄ left over *  molar mass

                                    = 0.0469 mol * 16 g/mol = 0.7504 g

So, the right choice is 0.74 grams of methane

3 0
3 years ago
How can you determine the number of atoms in a mole of a molecular compound
Brilliant_brown [7]
Well if you go to Quiz-let it gives the answer the mass of a mole of compound is determined by adding the atomic masses of the atoms making up the molecules
7 0
3 years ago
Which type of matter can be separated by physical means? A. atom B. element C. compound D. mixture
madreJ [45]

Answer:

b

Explanation:

A pure substance has a constant composition and cannot be separated into simpler substances by physical means. There are two types of pure substances: elements and compounds.

7 0
2 years ago
Read 2 more answers
Which statement describes the energy changes that occur as bonds are brokes and a chemical reaction
Leni [432]

Answer:

Energy is released when bonds are broken, and energy is absorbed when bonds are formed.

7 0
2 years ago
What is the pH of 15 mL of .2 M HCl
fenix001 [56]
Easy peasy! All we need to do is plug this formula into our calculator:

-log(M)

So, we'd plug in -log(.2), which is 0.7 :)
3 0
3 years ago
Other questions:
  • What is generally true about rate over the course of a reaction?. Rate decreases because there are more collisions as the reacti
    9·2 answers
  • Why is water being a universal solvent important to living things
    6·1 answer
  • The product of a combination reaction is Ca(OH)2. If one of the reactants is H20 wat is the other reactant
    14·2 answers
  • How did Mendeleev arrange the known elements in his periodic table?
    8·1 answer
  • Which of the following changes would have no effect on the equilibrium position of the reaction below? 2 NOBR (g) 2 NO (g)+ Br2
    7·1 answer
  • HELPPPPPPPP PLZZZZ MVP ME .!!!
    15·1 answer
  • Which chromosome cause apples to be a `paticular` color?
    7·1 answer
  • 17. A sample of oxygen gas has volume 150.0 mL, at 0.947 atm, what will be the volume of the gas at 750.12 mm of Hg if temperatu
    10·1 answer
  • Cho biết độ tan của NH4Cl trong nước ở 20oC và 70oC lần lượt là 37,2 g/100 gam nước và 60,2 gam/100 g nước. Hòa tan 166,8 gam NH
    15·1 answer
  • Gold (Au) is considered a(n)<br><br><br> Compound<br><br> Potatoes<br><br> Mixture<br><br> Element
    10·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!