List of top Chemistry Questions

H$_2$ can be added to ethylene in the presence of a heterogeneous catalyst such as solid. What might account for the initial attraction between the hydrogen molecules and the solid platinum?
Given the following notation for an electrochemical cell,
Pt(s) $|$ H$_2$(g)$|$ H$^+$(aq) $//$ Ag$^+$(aq)$|$Ag(s)
Which of the following represents the overall balanced (net) cell reaction?
Which of the following periodic properties increases with increasing atomic number within a family in the periodic table?
Using the above information, determine the standard reduction potential for the following reaction,
\[ 2M(s) + 3Zn^{2+}(aq) \rightarrow 2M^{3+}(aq) + 3Zn(s); \quad E^\circ = 0.90V \] \[ Zn^{2+}(aq) + 2e^- \rightarrow Zn(s); \quad E^\circ = -0.76V \]
If a mole of C$_3$H$_8$ is reacted with 2.5 moles of O$_2$ how many moles of H$_2$O will be produced ?
Which of the following demonstrates non-ideal behaviour of a gas?
What type of intermolecular bonding occurs in gaseous CH$_4$?
Given that
\[ \text{Zn}^{2+}(aq) + 2e^- \rightarrow \text{Zn}(s); \quad E^\circ_{\text{red}} = -0.76\,\text{V} \] \[ \text{Cr}^{3+}(aq) + 3e^- \rightarrow \text{Cr}(s); \quad E^\circ_{\text{red}} = -0.74\,\text{V} \] Calculate the equilibrium constant K at 25°C for the following balanced reaction,
\[ 3\text{Zn}(s) + 2\text{Cr}^{3+}(aq) \rightarrow 3\text{Zn}^{2+}(aq) + 2\text{Cr}(s) \]
Which of the following is true for an electrolytic cell?
Calcium chloride is sometimes sprinkled on winter sidewalks to melt snow and ice. If 333g of calcium chloride is dissolved completely in 1.00 kg of water, what will be the freezing point of the solution? (The molal freezing point depression constant for water is 1.86°C kg/mol)
The values of all of the following are reversed when a reaction is reversed except
The molar masses of C, H, A, CHOH, and CHF are very similar. How do their boiling points compare?
Which of the following is the \(K_b\) for the conjugate base of carbonic acid?
Which of the following groups contains only atoms that are paramagnetic in their ground state?
The acid dissociation constant for \( HC_6H_7O_6 \) is \( 8.0 \times 10^{-5} \). If a solution contains equal concentrations of \( HC_6H_7O_6 \) and \( C_6H_7O_6^- \), what will be the pH of the solution?
NaCl dissolves spontaneously in water. Based upon the following reaction, NaCl(s) $\rightarrow$ Na$^{+}$(g) + Cl$^{-}$(g)
What is the total heat needed to change 1g of water from -10°C to 110°C at 1 atm? \[ \Delta H_{fusion} = 80 \, \text{cal/g}, \Delta H_{vaporisation} = 540 \, \text{cal/g}, \text{specific heat of ice and steam are 0.5 cal/g°C} \]
What is the IUPAC name for the following cycloalkane?
20 g of NaCl is poured into a coffee cup calorimeter containing 250 mL of water. If the temperature inside the calorimeter drops 1°C by the time, the NaCl is totally dissolved, what is the heat of solution for NaCl and water? (specific heat of water is 4.18 J/g°C)
Which of the following solutions is the most concentrated? (assume 1 L of water has a mass of 1 kg)
Describe the phase change for H$_2$O as pressure is raised at 100°C.
Why can the relative strength of HCl and HClO$_4$ be determined in acetic acid but not in water?
Rechargeable batteries have become an essential part of our environmentally conscientious society. The nickel-cadmium cell battery is a rechargeable battery used in small electronic devices. The half reactions that take place in the nickel-cadmium battery during discharge are: Half reaction 1: Cd(OH)$_2$(s) + 2e$^{-}$ → Cd(s) + 2OH$^{-}$ Half reaction 2: 2NiO$_2$(s) + H$_2$O + 2e$^{-}$ → 2Ni(OH)$_2$(s) + 2OH$^{-}$ What is the oxidising agent in the nickel cadmium battery during discharge?
Aldehydes are readily oxidised to yield carboxylic acids but ketones are inert to oxidation. Which is the most likely explanation regarding this difference in reactivity?
Which molecular formula is also an empirical formula?