Elements, compounds and mixtures

9.Match each type of chemical bond to the type of compound it typically forms.

10.Arrange the following in the order they were historically proposed: Aristotle's four elements, Boyle's corpuscles, Dalton's atomic theory, Mendeleev's periodic table.

11.Which of the following are examples of chemical compounds? (Select all that apply)

12.A substance that cannot be broken down into simpler substances by chemical means is called:

13.A molecule of oxygen (O₂) is considered a chemical compound.

14.Which of the following statements about non-stoichiometric compounds is correct?

15.Which of the following is a mixture?

16.Match each term to its correct description.

17.Arrange the following substances in order of increasing complexity: compound, element, mixture.

18.A student is given a white powder. When heated strongly, it decomposes into a colourless gas and a black solid. The original powder could be classified as:

19.A molecule of ozone (O₃) is a chemical compound.

20.Which of the following are chemical compounds? (Select all that apply)

21.Match each substance to its classification.

22.The ancient Greek philosopher Aristotle believed that all matter was made of four elements: earth, air, fire, and water. According to modern chemistry, which of these is actually an element?

23.A sample of a substance is analysed and found to contain 5.85 g of sodium and 9.00 g of chlorine. Is this substance an element, compound, or mixture?

24.A student is given a sample of a white crystalline solid. When heated, it melts and then decomposes, releasing a colourless gas that turns limewater milky. The solid conducts electricity when dissolved in water. Which of the following is the most likely classification of the solid?

25.A mixture can be separated into its components by physical methods such as filtration or distillation.

26.A student has a sample of a grey powder. When a magnet is passed over it, some of the powder is attracted. The remaining powder is then dissolved in water, and the solution is filtered. A black solid remains on the filter paper, and the filtrate is colourless. The original sample is best classified as:

27.A student is given a sample that appears uniform and cannot be separated into components by filtration. However, when heated, it decomposes into two different gases. The original sample is best classified as:

28.The ancient Greek philosopher Aristotle believed that all matter was made of four elements: earth, air, fire, and water. According to modern chemistry, which of these four is actually an element?

29.Arrange the following in order of increasing complexity: atom, molecule of element, molecule of compound, mixture.

30.Which of the following is a chemical compound?

31.A molecule consisting of atoms of only one element is considered a chemical compound.

32.Match each substance to its correct classification (element, compound, or mixture).

33.Arrange the following in order of increasing complexity (simplest first): atom, molecule of compound, molecule of element, mixture.

34.According to the source, who first used the term 'compound' with a meaning similar to the modern one?

35.Arrange the following in the order they were historically proposed (earliest first): Dalton's atomic theory, Mendeleev's periodic table, Boyle's corpuscles, Aristotle's four elements.

36.A sample of a substance is heated and decomposes into two different gases. The original substance is most likely:

37.A student is given a sample of a grey powder. When a magnet is passed over it, some of the powder is attracted. The remaining powder is then dissolved in water, and the solution is filtered. A black solid remains on the filter paper, and a blue solution passes through. How many different substances are present in the original sample?

38.Which of the following are methods that can be used to separate a mixture into its components? (Select all that apply)

39.A compound can be separated into its elements by physical methods such as filtration or distillation.

40.Arrange the following in order of increasing complexity (simplest first): molecule of water (H₂O), atom of oxygen, mixture of hydrogen and oxygen gases, molecule of oxygen (O₂).

41.Complete the sentence:

42.How many different types of atoms are present in a molecule of sulfuric acid (H₂SO₄)?

43.What is the chemical formula for water?

44.Complete the sentence: A substance made of two or more different elements chemically bonded together in fixed proportions is called a ___.

45.A sample of a compound contains 2.0 g of hydrogen and 16.0 g of oxygen. What is the mass of oxygen that would combine with 5.0 g of hydrogen to form the same compound?

46.Complete the sentence.

47.Explain why carbon monoxide (CO) is considered a compound but oxygen gas (O₂) is not.

48.A sample of a compound contains 5.0 g of carbon and 13.33 g of oxygen. What is the mass of oxygen that would combine with 12.0 g of carbon in the same compound? Give your answer in grams to one decimal place.

49.Complete the sentence using the words provided.

50.State whether each of the following is an element, compound, or mixture: (a) iron (b) salt (c) air.

51.A compound has the formula MgO. If 24.3 g of magnesium combines with 16.0 g of oxygen, what mass of magnesium oxide is produced? Give your answer in grams to one decimal place.

52.Complete the sentence about chemical formulas.

53.Explain why a molecule of oxygen (O₂) is not considered a chemical compound, but a molecule of carbon monoxide (CO) is.

54.A sample of a compound contains 5.0 g of carbon and 13.33 g of oxygen. What is the mass of oxygen that would combine with 12.0 g of carbon in the same compound? Show your working.

55.How many different types of atoms are present in a molecule of sulfuric acid (H₂SO₄)?

56.A sample of a compound contains 2.0 g of hydrogen and 16.0 g of oxygen. What is the mass of oxygen that would combine with 5.0 g of hydrogen to form the same compound?

57.A sample of a compound contains 5.0 g of carbon and 13.33 g of oxygen. What is the mass of oxygen that would combine with 12.0 g of carbon in the same compound? Give your answer in grams to one decimal place.

58.A compound has the formula MgO. If 24.3 g of magnesium combines with 16.0 g of oxygen, what mass of magnesium oxide is produced? Give your answer in grams to one decimal place.