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Questions in chemistry

📝 Answered - The fire tetrahedron includes fuel, heat, combustion (chemical reaction), and A. Aerosol B. Oxygen C. Carbon monoxide D. Gasoline

📝 Answered - The production of water proceeds according to the following equation: [tex]$2 H_2(g)+O_2(g) \rightarrow 2 H_2 O(g)$[/tex] Which describes a way to speed up the collisions between hydrogen and oxygen molecules to produce more water? A. Use a less-intense source of heat on the reactants. B. Maintain the same temperature of the reactants. C. Place the reactants in a smaller container. D. Reduce the concentration of the reactants.

📝 Answered - Which balances the equation $Mg + O _2 \rightarrow MgO$? A. $Mg +2 O _2 \rightarrow 4 MgO$ B. $2 Mg +2 O _2+2 MgO$ C. $2 Mg + O _2 \rightarrow 2 MgO$ D. $2 Mg +2 O _2 \rightarrow 4 MgO$

📝 Answered - Ammonia, [tex]$NH _3(\Delta H_{ f }=-45.9 kJ)$[/tex], reacts with oxygen to produce water ([tex]$\Delta H_{ f }=-241.8 kJ$[/tex]) and nitric oxide, [tex]$NO (\Delta H_{ f }=$[/tex] 91.3 kJ ), in the following reaction: [tex]$4 NH_3(g)+5 O_2(g) \rightarrow 6 H_2 O(g)+4 NO(g)$[/tex] What is the enthalpy change for this reaction? Use [tex]$\Delta H_{r x n}=\sum(\Delta H_{f, \text { products }})-\sum(\Delta H_{f, \text { reactants }})$[/tex]. A. -902 kJ B. -104.6 kJ C. 104.6 kJ D. 900.8 kJ

📝 Answered - Element with the electron configuration $1 s^2 2 s^2 2 p^6 3 s^2 3 p^5$ is A. potassium B. fluorine C. sulfur D. chlorine E. carbon

📝 Answered - Activity 1 Which are Elements? Which are Compounds? Directions: Inside the box are the substances that are found in the cabinet. Identify the elements and compounds by accomplishing the table below. | IRON | SODIUM CHLORIDE (SALT) | SULFUR | CARBON | |---|---|---|---| | MAGNESIUM RIBBON | SUGAR | OIL | BAKING SODA | | COPPER | ALUMINUM | DISTILLED WATER | CHLORINE | | ELEMENTS | COMPOUNDS | |---|---| | | |

📝 Answered - What is the primary purpose of writing a lab report? A. to summarize the rules of the laboratory to the students who will use it B. to communicate the specifics of an experiment that was conducted C. to record observations in an organized format during the experiment D. to record which days a student worked in the laboratory

📝 Answered - How many atoms of each element are in the chemical formula [tex]$Ca ( OH )_2$[/tex]? A. 1 cakium, 1 oxygen, and 1 hydrogen B. 1 cakium, 2 oxygen, and 2 hydrogen C. 2 cakium, 1 oxygen, and 2 hydrogen D. 2 cakium, 2 oxygen, and 2 hydrogen

📝 Answered - The mass number of [tex]$Fe ^{2+}$[/tex] is 56. How many neutrons are there in a single [tex]$Fe ^{2+}$[/tex] atom? A. 28 B. 30 C. 56 D. 58

📝 Answered - Select the correct answer. Vitellium (V) has the following composition: V-188: 187.9122 amu, 10.861% V-191: 190.9047 amu, 12.428% V-193: 192.8938 amu; 76.711% Based on this data, what can you predict about the average atomic mass of vitellium? A. It will be equal to the arithmetic mean of the masses of the three isotopes. B. It will be closer to the mass of Vi-188. C. It will be closer to the mass of V-193. D. It will be equal to the mass of Vi-193.