Mass is always conserved in a physical change. Energy may be released or absorbed when a substance changes from one physical state to another. In a chemical change, a chemical reaction yields a completely new substance. A substance's particles are changed during a chemical reaction.
Answer:
3.01×10²⁶ molecules
Explanation:
From the question given above, the following data were obtained:
Mass of H₂ = 1 Kg
Number of molecules =?
From Avogadro's hypothesis,
1 mole of H₂ = 6.02×10²³ molecules
But 1 mole of H₂ = 2 × 1 = 2 g
Now, we shall determine the number of molecules present in 1 Kg (i.e 1000 g) of H₂ as follow:
From Avogadro's hypothesis,
2 g of H₂ = 6.02×10²³ molecules
Therefore,
1000 g of H₂ = 1000 × 6.02×10²³ / 2
1000 g of H₂ = 3.01×10²⁶ molecules
Thus, the number of molecules present in 1 Kg (i.e 1000 g) of H₂ is 3.01×10²⁶ molecules
True hope this helped u out cuh
The starting substances in a chemical reaction are called reactants - they are written on the left side of a chemical equation.
D=m/v ⇒ v=m/d
d=density
m=mass
v=volume
Density (Fe)=7.86 g/cm³=7.86 g/ ml
m=4.18 Kg.(1000 g/1Kg)=4180 g
v=m/d=(4180 g) / (7.86 g/ml)=531.8 ml
v=531.8 ml*(1 dl / 100 ml)=5.32 dl
v=5.32 dl
