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Questions in chemistry

[Terjawab] Select the correct answer. Which is the next logical step in balancing the given equation? [tex]3 CO_{(g)}+Fe_2 O_{3(s)} \rightarrow Fe_{(s)}+3 CO_{2(g)}[/tex] A. Place the coefficient 2 in front of iron(III) oxide. B. Leave it alone, as it is already balanced. C. Place the coefficient 2 in front of elemental fron. D. Replace the coefficient 3 in carkh monoxide with 6.

[Terjawab] Which of the following is a characteristic of carbon dioxide? A. It has a strong smell B. It is heavier than air C. It is flammable D. It is lighter than air

[Terjawab] 200 mL of a gas in a cylinder absorbs 800 J of heat and expands to three times its volume. Determine the internal energy change of the system.

[Terjawab] Select the correct answer. In the following combustion reaction of acetylene ($C_2H_2$), how many liters of $CO_2$ will be produced if 60 liters of $O_2$ is used, given that both gases are at STP? $2 C_2 H_2+5 O_2 \rightarrow 2 H_2 O+4 CO_2$ The volume of one mole of gas at STP is 22.4 liters. A. 48 liters B. 0.02 liters C. 240 liters D. 300 liters

[Terjawab] Which of the following is NOT a sign of a CO2 leak? A. Frost on the tank B. A strong chemical odor C. Hissing or whistling noises

[Terjawab] Select the correct answer. What is the theoretical yield of methanol [tex]$\left( CH _3 OH \right)$[/tex] when 12.0 grams of [tex]$H _2$[/tex] is mixed with 74.5 grams of CO? [tex]$CO +2 H _2 \rightarrow CH _3 OH$[/tex] A. 14.88 grams B. 47.65 grams C. 74.50 grams D. 85.12 grams E. 92.04 grams

[Terjawab] Daseous nyarogen burns in the presence of oxygen to form water: [tex]2 H_2+O_2 \rightarrow 2 H_2 O+ \text { energy }[/tex] Which molecule is oxidized and what kind of bond is formed? A. Oxygen, polar. B. Hydrogen, polar. C. Oxygen, nonpolar. D. Hydrogen, nonpolar.

[Terjawab] A typical aspirin tablet contains 323 mg acetylsalicylic acid [tex]$\left( HC _9 H _7 O _4\right)$[/tex]. Calculate the pH of a solution that is prepared by dissolving two aspirin tablets in enough water to make one cup (237 mL) of solution. Assume the aspirin tablets are pure acetylsalicylic acid, [tex]$K_{ a }=3.3 \times 10^{-4}$[/tex].

[Terjawab] The concentration of hydronium ions $(H_3 O ^{\prime})$ in a solution of (a) Calculate the concentration of hydroxide ions (OHF) in the solution of hydrofluoric acid (HF) at $25^{\circ} C$. (b) Write down the expression for the equilibrium constant for reaction (i). Calculate the concentration of un-ionised hydrofluoric in the solution at $25^{\circ} C$. for the hydrolysis of $NH _4 NO _3$ in water as represented by chemical equations below:

[Terjawab] Consider the chemical equations shown here. [tex]\begin{array}{l} P_4(s)+3 O_2(g) \rightarrow P_4 O_6(s) \quad \Delta H_1=-1,640.1 kJ \ P_4 O_{10}(s) \rightarrow P_4(s)+5 O_2(g) \quad \Delta H_2=2,940.1 kJ\\ \end{array}[/tex] What is the overall enthalpy of reaction for the equation shown below? Round the answer to the nearest whole number. [tex]P_4 O_6(s)+2 O_2(g) \rightarrow P_4 O_{10}(s)[/tex]