Isotopes are atoms of the same element that differ in the number of neutrons.
Remember that all the atoms of an element have the same number of protons. So the only difference between isotopes of an element is the number of neutrons.
86 Sr means that the mass number of this isotope is 86. Also, remember that the mass number is the number of protons plus the number of neutrons.
87 Sr means that the mass number of this isotope is 87.
So, 86 Sr and 87 Sr differ 1 neutron.
Answer: 1 neutron
To prevent the hydrolysis and to catalyse the reaction.
Explanation:
- Sulphuric acid is the catalyst and also a dehydrating agent in this reaction.
- Sulphuric acid is using in redox reaction because sulphuric acid is providing H+ ions which is necessary for this reaction to occur more quickly, but the sulphate ions from the sulphuric acid barely react during this process. So H2SO4 is adding in this reaction to make it more acidic.
- H2SO4 is preventing hydrolysis by providing excess H+ ions into the reaction. H2SO4 is stable towards the direction of oxidation.
Answer:

Explanation:
We know we will need a balanced chemical equation with masses and molar masses, so, let's gather all the information in one place.
You don't tell us what the reaction is, but we can solve the problem so long as we balance the OH.
M_r: 58.32
Mg(OH)₂ + … ⟶ … + 2HOH
m/g: 58.3
(a) Moles of Mg(OH)₂

(b) Moles of H₂O
The molar ratio is 2 mol H₂O = 1 mol Mg(OH)₂.

The reaction will form
of water.
Explanation:
they have different mass number but same atomic number