The solution is basic
The solution is neutral
The solution is acidic
The litmus paper is faulty
Correct answer is C
If a blue litmus paper turns red when dipped into a solution, it indicates the presence of an acid in the solution. Acids turn blue litmus paper red.
When a substance is oxidized, it
Loses electrons
Gains oxygen atoms
Gains electrons
Loses protons (H+ ions)
Correct answer is A
When a substance is oxidized, it loses electrons. Oxidation is a chemical reaction that involves the moving of electrons. Specifically, it's a process that involves the substance losing electrons. This is an old definition of oxidation, based on the oxygen's role in reactions. The modern definition of oxidation involves an increase in oxidation state by a molecule, atom, or ion.
What is the symbol used to represent an alpha particle?
α
γ
δ
β
Correct answer is A
An alpha particle is represented by the Greek letter 'α'. Alpha particles are a type of ionizing radiation ejected by certain types of radioactive materials. They consist of two protons and two neutrons, so they can be represented as a Helium-4 nucleus.
Which of the following is a common property of non-metals?
Exist as solids at room temperature
Tend to gain electrons in chemical reactions
High thermal conductivity
Readily form cations in chemical reactions
Correct answer is B
Tend to gain electrons in chemical reactions. Non-metals typically have a high electronegativity and tend to gain electrons to achieve a stable electron configuration. This results in the formation of negatively charged ions (anions) during chemical reactions.
25%
12%
75%
50%
Correct answer is C
The molar mass of methane (CH4) is calculated by adding the atomic masses of carbon (approximately 12 g/mol) and hydrogen (approximately 1 g/mol). Therefore, the molar mass of CH4 is 12 g/mol + 4 x 1 g/mol = 16 g/mol. The mass percentage of carbon in CH4 is given by (mass of carbon / total mass) x 100% = (12 g / 16 g) x 100% = 75%.