The matter that has the same composition and properties throughout is called pure chemical substance. So the answer is substance.
Answer:
Explanation:
Combination of oxidation and reduction reactions.
Where there is oxidation, there is reduction too.
Answer: Q= -34.6 J
Explanation: Use Q= mc∆T
c for solid lead is equal to 0.159 J/g°C
Substitute the values:
=14.8 g(0.159J/g°C)(23.7°C-38.4 °C)
= 14.8 g(0.159J/g°C) ( -14.7°C)
= -34.6 J
Cancel out the following units: g and °C so the remaining unit is in J.
Answer: Pure substances cannot be separated by physical means.
Explanation:
A pure substance is a substance which contains definite composition of only one type of component. Hence, it cannot be separated by physical means.
On the other hand, a mixture is a substance which contains two or more than two types of components and they can be separated by physical means as well.
Thus, option (a) is correct one that is pure substances cannot be separated by physical means.
Answer:
5 g of H₂ are contained in the vessel
Explanation:
A typical excersise of conversion:
We determine molar mass of H₂.
This is a dyatomic molecule, as molar mass of H is 1g/mol, molar mass of H₂ will be 2g/mol.
Let's make the conversion of units:
2.5 mol . 2g/mol = 5 g
5 g of H₂ are contained in the vessel
