Answer:
I think the answer is c!
Explanation:
Pure substances are further broken down into elements and compounds. Mixtures are physically combined structures that can be separated into their original components. A chemical substance is composed of one type of atom or molecule. hope this helps you!
Answer:
Electronegativity in group 1 decreases as we go from Lithium to Francium.
Explanation:
Electronegativity is defined as the tendency of an element to attract an electron pair towards itself.
In a group generally this tendency decreases from top to bottom as the size of the atom increases and hence the positive nucleus get far from the outer orbital.
In the same way group 1 elements i.e. from Lithium to Francium electronegativity decreases.
Answer : The molecule of ethane present in 64.28 L of ethane gas at STP is, 
molecule.
Solution :
At STP,
22.4 L volume of ethane present in 1 mole of ethane gas
64.28 L volume of ethane present in 
of ethane gas
And, as we know that
1 mole of ethane molecule contains 
molecules of ethane
2.869 moles of ethane molecule contains 
molecules of ethane
Therefore, the molecule of ethane present in 64.28 L of ethane gas at STP is, molecule.
Answer:
When atom undergoes the alpha emission the original atom convert into the atom having mass number less than 4 and atomic number 2 less than the starting atom.
Explanation:
Alpha radiations are emitted as a result of radioactive decay. The atom emit the alpha particles consist of two proton and two neutrons. Which is also called helium nuclei. When atom undergoes the alpha emission the original atom convert into the atom having mass number less than 4 and atomic number 2 less than the starting atom.
Properties of alpha radiation:
Alpha radiations can travel in a short distance.
These radiations can not penetrate into the skin or clothes.
These radiations can be harmful for the human if these are inhaled.
These radiations can be stopped by a piece of paper.
₉₂U²³⁸ → ₉₀Th²³⁴ + ₂He⁴ + energy
This problem is providing the chemical reaction whereby barium nitride reacts with water to produce barium hydroxide and ammonia, so the number of moles of barium nitride are required in order to produce 8.3 moles of ammonia. It asks for us to evaluate the student's setup, so we conclude the answer is C. "1 mol of NH3 should be replaced with 2 mol of NH3", according to:
<h3>Mole ratios:</h3>
In chemistry, stoichiometric calculations are used to figure out the moles or mass of a substance, given information about another one in the reaction. In this case, for the given chemical equation:
We evidence a 1:2 mole ratio of barium nitride to ammonia, for that reason, the student's setup:
Is incorrect, because the ammonia must be accompanied by a 2 rather than the 1 it is given there:
Thereby, the correct answer is C. "1 mol of NH3 should be replaced with 2 mol of NH3"
Learn more about mole ratios: brainly.com/question/15288923
