Answer: Option (a) is the correct answer.
Explanation:
When two or more atoms are chemically combined together then the product formed is known as a molecule.
These atoms can be bonded through either covalent or ionic bonds.
For example, a water molecule consists of two hydrogen atoms combined with an oxygen atom. Chemical formula of water is 
.
Thus, we can conclude that an element can be made of many elements.
Answer:
D is the most soluble in water at 60 degrees Celsius
Its temperature will rise until reaching 0° C Its temperature will remain at 0° C until all the ice melts
Answer:
1.35 moles of O²⁻
21.6 grams of O²⁻
Explanation:
We know that the charge on Aluminium ion is +3 (i.e. Al³⁺) while, the charge on Oxide ion is -2 (i.e. O²⁻). Therefore, the overall neutral Al₂O₃ compound has 2 Al³⁺ ions and 3 O²⁻ ions. Since, we can say that,
1 mole of Al₂O3 contains = 3 moles of O²⁻ ions
So,
0.450 moles of Al₂O₃ will have = X g of O²⁻
Solving for X,
X = 0.450 mol × 3 mol ÷ 1 mol
X = 1.35 moles of O²⁻
As the mass of an atom is mainly due to the presence of protons and neutrons hence, the addition of two electrons (-ve 2 shows two gained electron) to Oxygen will make a negligible change to the atomic masss of Oxygen because electron is said to be almost 1800 times lighter than proton. Hence, the ionic mass of O²⁻ will be 16 g/mol and the mass of given moles is calculated as,
Mass = Moles × Ionic Mass
Mass = 1.35 mol × 16 g/mol
Mass = 21.6 g
<em>The frequency of the wave with a wavelength of is</em> <u>3.748 × 10 ⁶ /s</u>.
I attached the working and the answer to the question below. I hope I was able to help.
Please note that C = speed of light (2.998 × 10⁸ m/s), ν = frequency and λ= wavelength.
