Tüm alıştırma soruları

A $250\text{ cm}^3$ sample of dry air is passed over excess heated phosphorus in a closed tube to remove all the oxygen gas present. Assuming oxygen constitutes $21\%$ by volume of dry air, what is the volume of the remaining gas mixture in $\text{cm}^3$?

An electromagnetic microwave signal used in telecommunication has a wavelength of $0.02\text{ m}$ in a vacuum. Given that the speed of light in a vacuum is $3.0 \times 10^8\text{ m/s}$, calculate the frequency of the signal in gigahertz ($\text{GHz}$).

A thin converging lens forms a real image of an object on a screen placed $60\text{ cm}$ from the lens. If the object is located $30\text{ cm}$ in front of the lens, what is the focal length of the lens in centimeters ($\text{cm}$)?

An alternating voltage source of root-mean-square (RMS) voltage $200\ \text{V}$ is connected across a series combination of a resistor with resistance $60\ \Omega$ and a capacitor with capacitive reactance $80\ \Omega$. Calculate the root-mean-square current in the circuit.

When $10.0\text{ g}$ of pure calcium carbonate ($\text{CaCO}_3$) is strongly heated, it completely decomposes into solid calcium oxide ($\text{CaO}$) and carbon(IV) oxide gas ($\text{CO}_2$). According to the Law of Conservation of Mass, if $5.6\text{ g}$ of calcium oxide remains in the container, what is the mass of carbon(IV) oxide gas released in grams?

A satellite revolves around a planet in a circular orbit of radius $1.0 \times 10^4 \text{ km}$ with an orbital period of $12 \text{ hours}$. Calculate the orbital period, in hours, of a second satellite orbiting the same planet in a circular path of radius $4.0 \times 10^4 \text{ km}$.

A satellite of mass $500\text{ kg}$ orbits a spherical planet of radius $R = 6.0 \times 10^6\text{ m}$ with surface gravitational acceleration $g = 10\text{ m/s}^2$. The satellite is transferred from an initial circular orbit of radius $2R$ to a higher circular orbit of radius $3R$. What is the minimum energy required, in megajoules ($\text{MJ}$), to perform this transfer?

An agricultural economist recorded the prices per bag of fertilizer (in thousands of Naira) across five regional markets as $₦12$, $₦15$, $₦18$, $₦21$, and $₦24$. What is the mean deviation of the fertilizer prices (in thousands of Naira)?

A gaseous mixture containing carbon monoxide ($\text{CO}$) and carbon dioxide ($\text{CO}_2$) has a total mass of $10.0\text{ g}$. If the mixture contains a total of $2.408 \times 10^{23}$ oxygen atoms, calculate the mass, in grams, of carbon dioxide ($\text{CO}_2$) present in the mixture. $[\text{C} = 12.0, \text{O} = 16.0, N_A = 6.02 \times 10^{23}\text{ mol}^{-1}]$

For the thermal decomposition of a compound, the standard enthalpy change ($\Delta H^\circ$) is $+117.0\text{ kJ mol}^{-1}$ and the standard entropy change ($\Delta S^\circ$) is $+180.0\text{ J K}^{-1}\text{ mol}^{-1}$. What is the minimum temperature, in kelvin ($\text{K}$), above which the reaction becomes spontaneous?

In a chemical reaction, the potential energy of the reactants is $45\text{ kJ mol}^{-1}$, while the potential energy of the activated complex at the peak of the energy profile diagram is $125\text{ kJ mol}^{-1}$. What is the activation energy for the forward reaction in $\text{kJ mol}^{-1}$?

For a reversible gaseous reaction $A + B \rightleftharpoons C + D$, the potential energy of the reactants is $120\text{ kJ mol}^{-1}$ and the potential energy of the products is $45\text{ kJ mol}^{-1}$. If the activation energy for the reverse reaction is $140\text{ kJ mol}^{-1}$, calculate the activation energy for the forward reaction in $\text{kJ mol}^{-1}$.

A chemical reaction has a standard enthalpy change ($\Delta H^\circ$) of $+75.0\text{ kJ mol}^{-1}$ and a standard entropy change ($\Delta S^\circ$) of $+250\text{ J K}^{-1}\text{mol}^{-1}$. Calculate the minimum temperature in Kelvin ($\text{K}$) at which this reaction becomes spontaneous.

A gas sealed inside a rigid container of fixed volume is connected to a pressure gauge that displays a gauge pressure of $1.50\text{ atm}$ at an initial temperature of $27^\circ\text{C}$. If the ambient atmospheric pressure is $1.00\text{ atm}$, calculate the temperature in degrees Celsius ($^\circ\text{C}$) to which the gas must be heated for its total absolute pressure to double.

A solution is formed by mixing $300\text{ cm}^3$ of $0.10\text{ mol dm}^{-3}$ tetraoxosulfate(VI) acid ($\text{H}_2\text{SO}_4$) solution with $700\text{ cm}^3$ of $0.10\text{ mol dm}^{-3}$ sodium hydroxide ($\text{NaOH}$) solution at $25^\circ\text{C}$. Assuming complete dissociation of both electrolytes, what is the pH of the resulting mixture?

During a chemical reaction between zinc metal and dilute hydrochloric acid, the volume of hydrogen gas produced was recorded over time. At $10\text{ s}$, the total volume of hydrogen gas collected was $15.0\text{ cm}^3$, and at $30\text{ s}$, the volume collected reached $45.0\text{ cm}^3$. What is the average rate of hydrogen gas evolution in $\text{cm}^3\text{ s}^{-1}$ over this $20\text{-second}$ time interval?

At $25^\circ\text{C}$, an aqueous solution of a weak monoacidic base has a concentration of $0.08\text{ mol dm}^{-3}$ and a degree of ionization ($\alpha$) of $0.025$ ($2.5\%$). What is the concentration of hydroxide ions, $[\text{OH}^-]$, in the solution in $\text{mol dm}^{-3}$?