Pure substances can or can not be chemically combined.
Pure substances can be either elements or compounds, but not mixture. Mixture are different substances mixing together without being chemically combined, such as air, which is a mixture of oxygen, carbon dioxide, water etc. Mixture can be separated by physical methods, like filtration or decantation.
Meanwhile, elements are the substances that cannot be further separated by any means. No matter physical or chemical methods. Examples of elements are oxygen, hydrogen, neon and all the other ones from the periodic table. Compounds are basically elements joining together, but they’re chemically combined which means their electrons (kind of subatomic particle) are either shared or given away. These elements can only be separated by chemical methods like electrolysis or heating.
Therefore, as long as the substance cannot be separated by physical methods, it can be considered as a pure substance. We can now conclude that pure substance can be (element) or can not be (compound) chemically combined.
Answer:
a) increases
b) decreases
c) does not change
d) increases
Explanation:
The vapour pressure of a liquid is dependent on;
I) the magnitude of intermolecular forces
II) the temperature of the liquid
Hence, when any of these increases, the vapour pressure increases likewise.
Similarly, the boiling point of a liquid depends on the magnitude of intermolecular forces present because as intermolecular forces increases, more energy is required to break intermolecular bonds.
Lastly, increase in surface area of a liquid does not really affect it's vapour pressure.
Answer:
the answer is b Li + Cl2 .....
Answer:
Stage 1: 1 days.
Stage 2: 2-3 days.
Stage 3: 4-5 days.
Stage 4: 6 days.
Stage 5 (a-c): 7-12 days.
Stage 6: c. 17 days.
Stage 7: c. 19 days.
Stage 8: c. 23 days.
