1. States of matter
A section of Chemistry, 5070
Listing 10 of 56 questions
Oxygen, sulfur, selenium, tellurium and polonium are in Group VI. State the percentage composition by volume of oxygen in dry air. State one large-scale use for oxygen. Two isotopes of polonium are shown. 4Po 4Po Explain why both isotopes have the same chemical properties. Give one difference in the atomic structure of these two isotopes. Selenium forms a compound that contains only selenium, oxygen and chlorine. The compound contains 9.6% oxygen by mass and 42.8% chlorine by mass. Calculate the empirical formula of this compound. empirical formula A sample of oxygen has a volume of 11.5 dm3 at room temperature and pressure. The temperature of the sample is decreased. The pressure remains constant. Describe and explain, using kinetic particle theory, what happens to the volume of the sample. The pressure of the sample is decreased. The temperature remains constant. Describe and explain, using kinetic particle theory, what happens to the volume of the sample. Calculate the mass of oxygen in the 11.5 dm3 sample at room temperature and pressure. Give your answer to two significant figures. mass g
5070_s21_qp_22
THEORY
2021
Paper 2, Variant 2
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Group VII includes the elements fluorine, chlorine, bromine and iodine. Chlorine is a green gas at room temperature and pressure. State the appearance of iodine at room temperature and pressure. Chlorine reacts with aqueous potassium iodide in a displacement reaction. Cl2+ 2I–2Cl –+ I2Explain, in terms of electrons, why chlorine is an oxidising agent in this reaction. State the oxidation number of iodine in I2. Describe what is observed during the displacement reaction. The rate of diffusion of fluorine gas is greater than that of chlorine gas under the same conditions of temperature and pressure. State what is meant by the term diffusion. Explain why the rate of diffusion of fluorine is greater than that of chlorine under the same conditions. The rate of diffusion of fluorine increases as the temperature increases. Suggest why using ideas about kinetic particle theory.
5070_s23_qp_22
THEORY
2023
Paper 2, Variant 2
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Questions Discovered
56