1.B
6.D
D because t<span>he mass of one mole (molar mass) of helium gas is </span>4.002602 g/mol. 4.002602 * 5=20.01309. Rounded equals 20. So, the answer is D.20 g.
All chemical reactions have a conversation of mass and energy.
Because:- There are only two laws for conversation in a chemical reaction. The conversation of mass, no mass can be created nor destroyed. Also, the law of conversation of mass states that no energy can be created nor destroyed in a chemical reaction. The charge can obviously change because they can bond and change charges.
3. Conducts electricity in aqueous solution.
Answer:
<em>The correct option is A) The atom has changed over the years.</em>
Explanation:
Option A is not correct because an atom does not change. It remains the same always. The structure of an atom will always contain neutrons, protons and electrons.
Scientific theories tend to change over time as new information is brought up. Novel techniques lead to more advanced experiments and results. As a result, a scientific theory is subjected to change whenever evidence is found for a new theory which challenges the older one.
The atomic theory has changed many times due to novel scientific techniques and experiments.
