Omg I wish I knew this one sorry
Hope you can figure it out
The object can no longer be returned to its original self, like ashes can't turn back to wood. The color changes, and bubbles.Also odor change, and gas formation.
Answer:
Number of molecules = 23.9 × 10²³ molecules
Number of moles = 3.97 mol
Explanation:
Mass of HNO₃ = 250 g
Number of moles = ?
Number of molecules = ?
Solution:
Number of moles = mass / molar mass
Number of moles = 250 g/63 g/mol
Number of moles = 3.97 mol
Number of molecules:
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.
For example,
18 g of water = 1 mole = 6.022 × 10²³ molecules of water
1.008 g of hydrogen = 1 mole = 6.022 × 10²³ atoms of hydrogen
For 250 g of HNO₃:
250 g/ 63 g/mol = 3.97 mole
3.97 × 6.022 × 10²³ molecules = 23.9 × 10²³ molecules
Valance electron are called
Answer:
a) 4869 kj will be released
b) 43.86 g of octane
Explanation:
The heat of combustion is the amount of heat released when one mole of a substance reacts with enough oxygen
since the heat of combustion is per mol of combustible substancewjat we are required to do in this problem is calculate number moles in the reactions although in a different manner
a) MW C3H6O = 158 g/ mol
mol C3H6O = 158 g × 1 mol/ 58.08 g
= 2.72 - 1790 kj / mol ×2.72 mol = 4869 kj
b) Here we are asked the mass of octane to produce 1950 kj of heat knowing that per mole of octane we get 5074.1 kj then
1 mol / 5074.1kj × 1950 kj= 0.384 mol
mass C8H18 = 0.384 mol × 114.23 g/ mol = 43.86 g
