Learn more about the properties, composition, and structure of substances (elements and compounds) with these Chemistry questions and answers. This Test can be used by students preparing for Chemistry in JAMB, WAEC, NECO or Post UTME.
The molecule that has a non-polar covalent bond is
HCl
\(NH_3\)
\(Cl_2\)
\(H_2O\)
Correct answer is C
In \(Cl_2\), the two chlorine atoms are identical and have the same electronegativity. Since both atoms have the same electronegativity, the electrons in the covalent bond are shared equally, resulting in a non-polar covalent bond. The molecule does not have a significant separation of charge and lacks a permanent dipole moment
Petrochemistry is an example of
applied chemistry
Biochemistry
Pure chemistry
Environmental chemistry
Correct answer is A
Applied chemistry refers to the practical application of chemical principles and techniques to solve real-world problems and create useful products. Petrochemistry is a branch of applied chemistry that deals specifically with the chemical processes and transformations involved in the extraction, refining, and processing of petroleum and its derivatives
Which of the following elements has its valence electrons in the s-orbital?
Aluminum
Phosphorus
Sodium
Carbon
Correct answer is C
Sodium is an alkali metal, and its atomic number is 11. This means that it has 11 electrons, and its electron configuration is \(1s^2 2s^2 2p^6 3s^1\). The valence electrons are the electrons in the outermost shell, which in this case is the 3s orbital.
Which of the following statements about the collision theory is correct?
Ineffective collision brings about chemical reaction
All collisions bring about reactions
The rate of reaction is proportional to the number of effective collisions
Collision of molecules will split the molecules to react
Correct answer is C
The rate of reaction is proportional to the number of effective collisions. This means that if the number of collisions increases, the rate of reaction will also increase. These successful collisions are known as effective collisions. The rate of reaction is directly proportional to the number of effective collisions between reactant molecules. In other words, the more frequent and successful the collisions, the faster the rate of the reaction.
66.00
65.50
65.00
65.40
Correct answer is D
Isotope \(^{65}X_{30}\) (with a mass of 65 and an abundance of 60%):
Relative mass contribution = (65 * 60%) = 39.00
Isotope \(^{66}X_{30}\) (with a mass of 66 and an abundance of 40%):
Relative mass contribution = (66 * 40%) = 26.40
Now, add the relative mass contributions of both isotopes:
Relative atomic mass \(A_r\) = 39.00 + 26.40 = 65.40
So, the relative atomic mass of element X is 65.40. The correct option is:
65.40