Answer:
1. Elements
2. one
3. properties
4. Chemical
5. metal
6. non-metal
7. metalloids
8. Compounds
9. one
10. more
11. components
12. chemical process
Explanation:
In the given paragraph a brief about the difference between element and compound is given.
Elements are made up of the same type of atoms and each element is made up of one atom, that is they cannot be broken down into any other substance. Each element is different from each other due to its properties, though some have the same physical properties but are different in chemical properties. Elements can be classified as metals such as iron and silver, non-metals such as oxygen and hydrogen, and metalloids such as boron and silicon.
Compounds are a combination of one or more elements such as water and salt. Compounds can be easily broken down into components through a chemical process.
Hence, the correct answer is:
1. Elements
2. one
3. properties
4. Chemical
5. metal
6. non-metal
7. metalloids
8. Compounds
9. one
10. more
11. components
12. chemical process
Given the concentration of aniline hydrochloride is 
Aniline hydrochloride is the conjugate acid of aniline a weak base.
pH can be calculated from 
anilinium ion the conjugate acid of aniline.
Answer:
Option A.
2Na + 2H2O —> 2NaOH + H2
Explanation:
To know which option is correct, we shall do a head count of the number of atoms present on both side to see which of them is balanced. This is illustrated below below:
For Option A:
2Na + 2H2O —> 2NaOH + H2
Reactant >>>>>>> Product
2 Na >>>>>>>>>>> 2 Na
4 H >>>>>>>>>>>> 4 H
2 O >>>>>>>>>>>> 2 O
Thus, the above equation is balanced.
For Option B:
2Na + 2H2O —> NaOH + H2
Reactant >>>>>>> Product
2 Na >>>>>>>>>>> 1 Na
4 H >>>>>>>>>>>> 3 H
2 O >>>>>>>>>>>> 1 O
Thus, the above equation is not balanced.
For Option C:
2Na + H2O —> 2NaOH + H2
Reactant >>>>>>> Product
2 Na >>>>>>>>>>> 2 Na
2 H >>>>>>>>>>>> 4 H
1 O >>>>>>>>>>>> 2 O
Thus, the above equation is not balanced.
For Option D:
Na + 2H2O —> NaOH + 2H2
Reactant >>>>>>> Product
1 Na >>>>>>>>>>> 1 Na
4 H >>>>>>>>>>>> 5 H
2 O >>>>>>>>>>>> 1 O
Thus, the above equation is not balanced.
From the illustrations made above, only option A is balanced.
Answer:
Hot material near Earth's surface is more dense and sinks, and when it cools, it becomes less dense and rises.
Explanation:
Convection is a process by which less dense material rises and more dense material sinks near Earth's surface. Water, air, rocks and other materials expands when temperature rises and they become less dense. When the water is heated it becomes vapors and carries away thermal energy from the water.
