Answer:
Explanation:
First write all numerators above the common denominator
4/5 - 1/2 - 1/2=
- 1/2
Subtract the numbers
- 1/2 =
- 
Write all numerators above the least common denominator 10
- =
Subtract the numbers and you got your answer :)
Answer : The amount of in kilojoules released is, -5.53 kJ
Explanation :
Formula used :
where,
q = heat released = ?
c = specific heat of ethanol = 
m = mass of ethanol = 23.4 g
= final temperature = 
= initial temperature = 
Now put all the given values in the above formula, we get:
Therefore, the amount of in kilojoules released is, -5.53 kJ
the answer is Cl2Mn . The 2 is below .
Answer:
Mass = 17.8 g
Explanation:
Given data:
Number of atoms of Ca = 2.68 × 10²³
Mass in gram = ?
Solution:
Avogadro number:
The given problem will solve by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.
The number 6.022 × 10²³ is called Avogadro number.
1 mole = 6.022 × 10²³ atoms
2.68 × 10²³ atoms × 1 mole /6.022 × 10²³ atoms
0.445 mol
Mass in gram;
Mass = number of moles × molar mass
Mass = 0.445 mol × 40 g/mol
Mass = 17.8 g
Molecular mass of Mg(OH)2
= Atomic mass of Mg + 2(Atomic mass of O) + 2(Atomic mass of H)
= 24 g/mol + 2(16 g/mol) + 2(1 g/mol )
= 58 g/mol
Molecular mass of Fe2O3
= 2(Atomic mass of Fe) + 3(Atomic mass of O)
= 2(56 g/mol) + 3(16 g/mol)
= 160 g/mol
