A. Water can dissolve a wide variety of substances
Approximately 99 because there is the same amount of electrons and the only things that go into the nucleus is protons and neutrons.
Answer:
Yes.
Explanation:
Substances are made up of matter or matter are made up of tiny molecules or atoms that occur naturally or some are synthetic or man made.
All matter are made up of substances called elements and each elements have its own physical and chemical properties and cannot be broken easily by ordinary chemical reactions.
Of all the 118 elements only 92 occur naturally and 26 are man made or synthetic which are made in the laboratories.
Answer:
0.44g
Explanation:
Given parameters:
Mass of magnesium hydroxide = 0.645g
Solution
The balanced reaction equation is shown below:
Mg(OH)₂ → MgO + H₂O
From the equation above, we see that the number of atoms are conserved.
To find the mass of magnesium oxide produced, we find the number moles of the decomposed magnesium hydroxide first:
Molar mass of Mg(OH)₂ = 24 + 2(16+1) = 58g/mol
Number of moles of Mg(OH)₂ = 
= 
= 0.011mole
Now, from the balanced equaiton, we know that:
1 mole of Mg(OH)₂ produces 1 mole of MgO
Therefore, 0.011mole of Mg(OH)₂ will produce 0.011mole of MgO
so mass of MgO = number of moles of MgO x molar mass of MgO
Molar mass of MgO = 24 + 16 = 40g/mol
mass of MgO = 0.011 x 40 = 0.44g