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Fundamentals of chemistry
Class 9 · Chemistry · 19 questions
Name: ____________________ Date: ____________
What is the relative atomic mass of oxygen?
- A 16
- B 2
- C 32
- D 8
How many atoms are present in one molecule of H2SO4?
- A 3
- B 9
- C 5
- D 7
What is the mass of one mole of water, H2O? (H = 1, O = 16)
- A 20 g
- B 18 g
- C 34 g
- D 16 g
The number of particles in one mole of any substance is:
- A 3.01 x 10^23
- B 1.2 x 10^24
- C 6.02 x 10^22
- D 6.02 x 10^23
A substance made of only one kind of atom is called:
- A A solution
- B A mixture
- C An element
- D A compound
How many moles are there in 36 g of water? (molar mass 18 g/mol)
- A 3
- B 2
- C 0.5
- D 1
Which of these is a compound?
- A Oxygen
- B Iron
- C Hydrogen
- D Water
The symbol of sodium is:
- A S
- B Na
- C So
- D Sd
The formula of carbon dioxide is:
- A CO2
- B CO
- C C2O
- D CO3
Which of these is a mixture?
- A Water
- B Salt
- C Air
- D Iron
A pure substance made of one kind of atom is a(n):
- A Element
- B Mixture
- C Compound
- D Solution
The molar mass of carbon dioxide (C = 12, O = 16) is:
- A 28 g/mol
- B 60 g/mol
- C 44 g/mol
- D 32 g/mol
How many moles are in 9 g of water? (H = 1, O = 16)
- A 2 mol
- B 0.5 mol
- C 1 mol
- D 0.9 mol
The number of particles in one mole is:
- A 6.022 × 10²³
- B 3.011 × 10²³
- C 1.66 × 10⁻²⁴
- D 6.022 × 10²⁰
One mole of any gas at STP occupies:
- A 11.2 dm³
- B 22.4 dm³
- C 44.8 dm³
- D 1 dm³
The relative atomic mass of an element is measured compared with one twelfth of an atom of:
- A Nitrogen-14
- B Hydrogen-1
- C Oxygen-16
- D Carbon-12
An atom that has lost one electron becomes a:
- A Anion
- B Neutral atom
- C Cation
- D Molecule
What is the mass of 2 mol of sodium chloride? (Na = 23, Cl = 35.5)
- A 23 g
- B 58.5 g
- C 35.5 g
- D 117 g
Which of these is a molecule of an element?
- A CO₂
- B H₂O
- C NaCl
- D O₂
Answer key
1. A, 2. D, 3. B, 4. D, 5. C, 6. B, 7. D, 8. B, 9. A, 10. C, 11. A, 12. C, 13. B, 14. A, 15. B, 16. D, 17. C, 18. D, 19. D
Oxygen atoms have a relative atomic mass of 16.
2 hydrogen + 1 sulphur + 4 oxygen = 7 atoms.
Molar mass = 2 x 1 + 16 = 18 g.
This is Avogadro's number.
An element contains only one kind of atom.
Moles = mass / molar mass = 36 / 18 = 2.
Water contains hydrogen and oxygen chemically combined.
Sodium is Na, from natrium.
Carbon dioxide is CO2.
Air contains several gases that are not chemically combined.
An element contains only one kind of atom.
12 + 2(16) = 44.
Molar mass is 18, so 9 ÷ 18 = 0.5 mol.
This is Avogadro's number.
Molar volume at STP is 22.4 dm³.
Carbon-12 is the standard.
Losing electrons leaves a positive charge, which is a cation.
Molar mass 58.5 g/mol times 2 gives 117 g.
O₂ contains atoms of one element only.