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
First, you need to have a periodic table that contains the electronegativities values. once you have them, you just need to subtract the values of the atoms and each bond. I have attached a table with these values. also, it does not matter then order in which you subtract them because they are always positive values. even though you get negative values in your calculator, just make it positive.
H-S----> 2.1 - 2.5= 0.4
H-Cl---> 2.1 -3.0=0.9
H-O---> 2.1- 3.5= 1.4
H-F----> 2.1 - 4.0= 1.9
HF is the most polar because it has the highest electronegativity difference.
Calcium carbonate is CaCO3.
So there is calcium, symbol is Ca and an atomic number of 20.
Carbon: symbol is C and an atomic number of 6.
Oxygen: symbol is O and an atomic number of 8.
In one molecule of CaCO3, there is one atom of Ca, one atom of C, and three atoms of O as shown by the subscript next to O in the formula. There are no other subscripts to indicate more than one atom of the other elements, so there is only one atom of the other two elements
Because in SI, the expectation is that area and volume will be expressed in terms of a linear dimension( the metre) or its multiples.
