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Questions in chemistry

📝 Answered - A beaker with water and the surrounding air are all at 24°C. After ice cubes are placed in the water, heat is transferred from: 1. the ice cubes to the air 2. the beaker to the air 3. the water to the ice cubes 4. the water to the beaker

📝 Answered - Which mixture will not yield hydrogen gas? A. Sodium and water B. Calcium and water C. Zinc and hydrochloric acid D. Zinc and concentrated nitric acid E. Steam and red hot iron

📝 Answered - A substance releases heat when it changes from: a. liquid to solid b. solid to gas c. liquid to gas d. solid to liquid

📝 Answered - Which element reacts spontaneously with 1.0 M HCl(aq) at room temperature? 1. Copper 2. Gold 3. Silver 4. Zinc

📝 Answered - Which of the following statements is true of the critical temperature of a pure substance? A. The critical temperature is the temperature above which the liquid phase of a pure substance can exist. B. The critical temperature is the temperature above which the liquid phase of a pure substance cannot exist. C. The critical temperature is the temperature below which the liquid phase of a pure substance cannot exist. D. The critical temperature is the temperature at which all three phases can coexist. E. The critical temperature is the temperature at which the pure substance reaches, but cannot go beyond, the critical pressure.

📝 Answered - Salt water is classified as a 1. compound because the proportion of its atoms is fixed 2. compound because the proportion of its atoms can vary 3. mixture because the proportion of its components is fixed 4. mixture because the proportion of its components can vary

📝 Answered - What is the approximate mass of a proton? (1) 1 u (2) 0.0005 u (3) 1 g (4) 0.0005 g

📝 Answered - An electron in a sodium atom gains enough energy to move from the second shell to the third shell. The sodium atom becomes: 1. a positive ion 2. a negative ion 3. an atom in an excited state 4. an atom in the ground state

📝 Answered - Which quantity represents the number of protons in an atom? (a) atomic number (b) oxidation number (c) number of neutrons (d) number of valence electrons

📝 Answered - The elements in Group 2 have similar chemical properties because each atom of these elements has the same: (a) atomic number (b) mass number (c) number of electron shells (d) number of valence electrons