Answer:
Calcium
Explanation:
"Calcium is a mineral that is necessary for life. In addition to building bones and keeping them healthy, calcium enables our blood to clot, our muscles to contract, and our heart to beat. About 99% of the calcium in our bodies is in our bones and teeth.
"
6.337 X 10^-7. To get this, divide the atoms by Avogadro's number, them multiply my the molar mass of Ni.
Answer:
pH = 4
Solution is acidic
Explanation:
Given data;
Hydronium ion concentration = 1 × 10⁻⁴ M
pH of solution = ?
Solution:
pH = -log [H₃O⁺]
pH = -log [ 1 × 10⁻⁴ ]
pH = 4
According to pH scale the pH 7 is neutral while the pH less than 7 is acidic and greater than 7 is basic. The given solution has pH 4 it means solution is acidic.
Answer:
A chemical change is required to separate the elements present in it.
Explanation:
The only true statement from the choices given is that water as a pure substance requires a chemical change to separate the elements present in it.
Water is a molecule consist of two atoms of hydrogen and one atom of oxygen.
- The atoms are covalently bonded together.
- A chemical process, the electrolysis of water is often used to separate the atoms of a water.
- Physical changes cannot be used to separate the atoms of water.
- Water is a compound which consists of two elements.
Therefore, we see that only the first choice satisfies this problem.
It's pretty easy to balance equations! Basically you want to make sure that the number of each compound is equal on both sides of the arrow.
For example number one is
Fe + H2SO4 -> Fe2(SO4)3 + H2
A 3 in front of H2SO4 because there's a subscript of 3 on the right side.
Then a 3 in front of H2 because of the previous step.
Then add a 2 in front of Fe because of the 2 subscript in Fe2(SO4)3
Then add a 1 in front of Fe2(SO4)3 because you already have an equal number of each element.
<u>2</u>Fe + <u>3</u>H2SO4 -> <u>1</u>Fe2(SO4)3 + <u>3</u>H2
I hope this explanation helps! You should really do your homework because practice is everything when it comes to chemistry. You'll need to know how to do it for exams.
