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Questions in chemistry

[Homework Help] What is the predicted order of first ionization energies from highest to lowest for lithium (Li), sodium (Na), potassium $( K )$, and rubidium $( Rb )$? A. $Rb > K > Na > Li$ B. $K > Rb > Na > Li$ C. $Li > Na > K > Rb$ D. $Rb > K > Li > Na$

[Homework Help] What is the first quantum number of a $1 s^2$ electron in phosphorus, $1 s^2 2 s^2 2 p^6 3 s^2 3 p^3$? A. $n=1$ B. $n=0$ C. $n=2$ D. $n=3

[Homework Help] Select the correct answer. Which of the following is true for balancing equations? A. The number of products should be equal to the number of reactants. B. The properties of products should be the same as the properties of reactants. C. There must be an equal number of compounds on both sides of the equation. D. There must be an equal number of atoms of each element on both sides of the equation.

[Homework Help] Can you use melting point to determine the identity of an unknown solid? The metal is observed to begin to melt when the temperature of its container is approximately $29^{\circ} C$. The metal is most likely: copper lead mercury tin gallium | Substance | Melting Point | |---|---| | copper | $1,085^{\circ} C$ | | lead | $327.5^{\circ} C$ | | mercury | $-38.6^{\circ} C$ | | tin | $232^{\circ} C$ | | gallium | $29.78^{\circ} C$

[Homework Help] Select the correct answer. Which is a balanced chemical equation? A. $C _7 H _{16}+5 O _2 \rightarrow 6 CO _2+4 H _2 O$ B. $C _7 H _{16}+11 O _2 \rightarrow 7 CO _2+8 H _2 O$ C. $C _7 H _{16}+14 O _2 \rightarrow 7 CO _2+5 H _2 O$ D. $C _7 H _{16}+22 O _2 \rightarrow 14 CO _2+16 H _2 O$

[Homework Help] Calculate the work done when one mole of an ideal gas at 298 K and 5 atm pressure is allowed to expand irreversibly against the constant outside pressure of 1 atm until the internal pressure becomes the same as the outside pressure.

[Homework Help] 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.

[Homework Help] 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

[Homework Help] 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.

[Homework Help] 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