Answer:
If one element is a metal and the other element is a non metal
Explanation:
Ionic bonds are formed between metals and non metals. The nonmetal atom receives electron(s) from a metal atom to form an ionic substance. This means that ionic substances are basically an ion pair.
Covalent bonds are mostly formed between two nonmetals. These elements share electrons with each other in order to form the compound.
Answer:
- Question 19: the three are molecular compounds.
Explanation:
<em>Question 19.</em>
All of them are the combination of two kinds of different atoms in fixed proportions.
- C₂H₄: two carbon atoms per four hydrogen atoms
- HF: one hydrogen atom per one fluorine atom
- H₂O₂: two hydrogen atoms per two oxygent atoms
Thus, they all meet the definition of compund: a pure substance formed by two or more different elements with a definite composition.
Molecular compounds are formed by covalent bonds and ionic compounds are formed by ionic bonds.
Two non-metal elements, like H-F, C - C, C - H, H-O, H - H, and O - O will share electrons forming covalent bonds to complete their valence shell. Thus, the three compounds are molecular and not ionic.
<em>Question 20. </em>Formula of copper(II) sulfate hydrate with 36.0% water.
Copper(II) sulfate is CuSO₄. Its molar mass is 159.609g/mol
Water is H₂O. Its molar mass is 18.015g/mol
Calling x the number of water molecules in the hydrate, the percentage of water is:

From which we can solve for x:

Thus, there are 5 molecules of water per each unit of CuSO₄, and the formula is:
Because the rate at which water vapour condenses gets increase slowly to get equal to the rate of evaporation of the water.
Explanation:
When a bottle is partly filled with liquid water is leaves space for vapours to escape and get condensed equally.
When sealed and kept below the lamp the rate of condensation increases due to the empty space in the bottle for getting vapours cool down.
A point arrives when evaporation equates the condensation of the liquid in bottle becomes stable because vapours cannot pass the bottle eventually condense and become liquid.