FREE IB Chemistry Questions and Answers
H2S + H2O --> HS- + H3O+
What is the conjugate base of H2S in the aforementioned reaction?
A pair of two molecules that differ only in the presence of a proton is referred to as a conjugate acid/base pair. The base of a conjugate acid has an extra proton added to it. The acid with one fewer proton is known as the conjugate base. The species with one fewer proton, HS-, is the conjugate base of
What is the most electronegative of the following elements?
The propensity of an atom to draw electrons into a covalent connection is known as electronegativity. In general, electronegativity rises as one moves up groups and through periods. The elements in the periodic table's upper right corner are the most electronegative as a result. The most electronegative element on the periodic table, oxygen, is the only one in the question's context.
What phrase describes a transition from a solid to a gas quickly?
A transition from a liquid to a gas is called vaporization. Phase transition from gas to solid is called deposition. A phase change is not described by effervescence. A transition from a solid to a liquid phase is fusion. As a result, sublimation must involve a transition from solid to gas.
A cell submerged in purified water has enlarged. Why?
The water must have flowed in and made the cell swell because the cell was hypertonic to the water (had a larger concentration of salts or other dissolved substances). The cell was in a hypotonic environment because the water is hypotonic to the cell in this case.
Which of the following quantum number sequences cannot exist for an electron?
Any positive integer value can be used as the principal quantum number. The value of the angular quantum number can range from to (n-1). The magnetic quantum number can range from -l to +l in value. Because the magnetic quantum number is greater than the angular quantum number, the set of quantum numbers n = 2, l = 1, ml = 2, and s = -1⁄2 cannot exist.
Which of the following scenarios ensures that an unplanned, forward-moving reaction will take place?
Higher energy reactants always move to lower energy products in a spontaneous process. As a result, there is a negative energy differential between the reactants and the products. Therefore, a decrease in Gibbs free energy ensures a spontaneous response that moves ahead.
Which of the subsequent hybridizations would allow one pi bond to form?
Sp2 hybridization permits the creation of a single double bond (flat, triangular formation). Sp3 only permits single bonds, whereas Sp permits triple bonds. There is no hybridization in S2.
3.0 moles of H20 are used to dissolve 80.0 grams of NaOH. What percentage of NaOH by moles is present in this solution?
A compound's mole fraction is expressed as (moles of the specified compound) / (total moles of system). There are five total moles in the system and two moles of NaOH in this question. This results in the mole fraction being written as 2/5, or.40.
Which of the following elements has an atomic radius that is the largest?
Atomic radius grows down a group and decreases over a period. The first group's elements will be the biggest throughout that time. The element with the greatest atomic number, which is at the bottom of the list, will have the largest atomic radius. As a result, of the elements listed, rubidium has the biggest atomic radius.
In order to induce a non-spontaneous reaction to occur, electrolysis needs energy input. False or true?
The assertion is true. Electrical current can induce a non-spontaneous reaction to proceed, which is known as electrolysis.
At 25 degrees Celsius, which of the following elements is a liquid?
Only bromine and mercury are liquid elements when the temperature is 25 degrees Celsius. Mercury is the sole element in the context of the question that is a liquid at 25 degrees Celsius.