5. B air is a mixture of many elements, but is not a chemically fused.
6. B Beef stew, composition varies throughout.
7. A. They can be chemically separated into their component elements, but they are all homogenous, and as such, have constant composition, which differs from the components properties, as the components must undergo a chemical change to become compounds.
Chromium , silver, zinc...
Answer:
1.02mole
Explanation:
The reaction equation is given as:
2NaOH + H₂SO₄ → Na₂SO₄ + 2H₂O
Given:
Mass of H₂SO₄ = 50g
Unknown:
Number of moles of NaOH = ?
Solution:
To solve this problem, we first find the number of moles of the acid given;
Number of moles =
Molar mass of H₂SO₄ = 2(1) + 32 + 4(16) = 98g/mol
Now;
Number of moles =
= 0.51mole
From the balanced reaction equation:
1 mole of H₂SO₄ will be neutralized by 2 mole of NaOH
0.51 mole of H₂SO₄ will be neutralized by 2 x 0.51 = 1.02mole of NaOH