a deliquescent salt
a neutral salt
an alkaline gas
an acid anhydride
Correct answer is D
The compound that could be dried by using conc. tetraoxosulphate (VI) acid and not calcium oxide is an acid anhydride.
Acid anhydrides are compounds that can react with water to form acids. When acid anhydrides are exposed to air, they will absorb water from the air and become hydrated. This can make them difficult to dry with calcium oxide, which is a base.
2.15 mol dm-3
0.74 mol dm-3
0.60 mol dm-3
0.57 mol dm-3
Correct answer is B
Molar mass of Na2SO4 = 2(Na) + S + 4(O) = 2(23.0 g/mol) + 32.1 g/mol + 4(16.0 g/mol) = 46.0 g/mol + 32.1 g/mol + 64.0 g/mol = 142.1 g/mol
Now, we can calculate the number of moles of Na2SO4 in the solution:
Number of moles = Mass of the salt / Molar mass
Number of moles = 10.5 g / 142.1 g/mol ≈ 0.0739 mol
Next, we need to find the volume of the saturated solution, given as 100 cm³, and convert it to liters:
Volume of solution = 100 cm³ = 100 cm³ / 1000 cm³/dm³ = 0.1 dm³
Finally, we can calculate the solubility in mol/dm³:
Solubility = Number of moles / Volume of solution
Solubility = 0.0739 mol / 0.1 dm³ ≈ 0.739 mol/dm³
Rounded to two decimal places, the solubility of sodium tetraoxosulphate (VI) at 30°C is approximately 0.74 mol/dm³.
Therefore, the correct option is:
0.74 mol dm-3.
Solubility = 10.5 g / 100 cm3 * 142 g/mol = 0.739 mol/dm3
The periodic property that is used to determine whether a covalent molecule is polar or not is
atomic radius
ionization energy
electron affinity
electronegativity
Correct answer is D
The periodic property that is used to determine whether a covalent molecule is polar or not is electronegativity.
Electronegativity is a measure of the ability of an atom to attract electrons in a chemical bond. The greater the electronegativity of an atom, the more strongly it will attract electrons.
The gas that is less dense than air is
nitrogen
chlorine
Carbon(IV) oxide
Oxygen
Correct answer is A
The density of a gas is directly proportional to its molar mass. This means that gases with a lower molar mass will be less dense than gases with a higher molar mass. Nitrogen (N2) has a molar mass of 28 g/mol, which is less than that of air (approximately 29 g/mol), making it less dense than air.
The primary component of natural gas
ethane
methane
butane
propane
Correct answer is B
Natural gas is a fossil fuel primarily composed of hydrocarbon gases. The primary component of natural gas is methane, which typically makes up a significant portion of the gas mixture. Methane is a simple hydrocarbon with one carbon atom and four hydrogen atoms (CH4). It is the main component of natural gas, often accounting for over 90% of its composition.