Question

Y'all i need this to be doneee!! Don't answer this quest if you don't know what's the answer, please explain why'd you chose that letter:> tysm!!


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Answer 1

Questions:

6. _____ is the mass of 1 mole of a substance expressed in grams

7. How many Aluminium atom/atoms are there in Al(OH)₃

8. The molar mass of H₂O is

9. What is the percent by mass of Carbon in Methane (CH₄)

10. How can you apply the knowledge on Percentage composition?

Answers:

Answer 6:

Molar Mass is the mass of 1 mole of a substance expressed in grams

Explanation:

As the name suggests, mass of 1 mole of a substance in grams is denoted by Molar Mass.

Talking about other options,

• Percentage composition gives the percentage of 1 element in a compound.
• Number of particles = Number of moles multiplied by Avogadro number.
• Number of moles = Mass divided by Molar Mass.

Answer 7:

a) 1

Explanation:

Al(OH)₃ refers to Aluminium Hydroxide

Al(OH)₃ contains 1 atom of Aluminium, 3 atoms of oxygen and 3 atoms of Hydrogen.

Answer 8:

a) 18.008 g/mol

Explanation:

H₂O contains 2 atoms of Hydrogen and 1 atom of Oxygen.

So, Molar mass = 2 (Hydrogen mass) + 1 (Oxygen mass)

⇒ Molar mass = 2 (1.008) + 1 (16)

⇒ Molar mass = 2.016 + 16

⇒ Molar mass = 18.016

≈ Molar mass = 18.008 g/mol (According to given options)

Answer 9:

b) 75 %

Explanation:

Here, for finding the percentage composition; we shall find out the molar mass.

Molar mass of CH₄ = Carbon mass + 4(Hydrogen mass)

⇒ Molar mass of CH₄ = 12.01 + 4(1.008)

⇒ Molar mass of CH₄ = 12.01 + 4.032

⇒ Molar mass of CH₄ = 16.042

Now, percentage of carbon in methane

$= \: \sf{\dfrac{12.01}{16.042} \times 100}$

= 75 %

Answer 10:

a) In identifying the correct amount of substance present in a sample.

Explanation:

As we did in the previous question, Percentage composition gives the exact percentage of an atom present in a compound.