Answer:
C. The mass of an electron is much less than the mass of a proton or
a neutron.
Explanation:
When we compare the mass of an electron to that of proton or neutron, the mass of an electron is much less than the mass of a proton or a neutron.
Electrons are negatively charged particles in an atom
Protons are positively charged particles
Neutrons do not carry any charges.
- The relative mass of an electron compared to that of a proton is
- This is a very small value
- Electrons generally have mass of 9.11 x 10⁻³¹kg
- Protons weigh 1.67 x 10⁻²⁷kg
- Neutrons weigh 1.68 x 10⁻²⁷kg
We can see that electrons have very small mass and this is why when calculating the mass of an atom, we use the sum of the number of protons and neutrons.
Answer:
volume of 
Explanation:
Firstly balance the given chemical equation,

From the given balance equation it is clearly that,
2 mole of Li gives 1 mole of H2 gas
⇔
⇔
⇔
hence
3 mole of Li will give 1.5 mole H2 gas
therefore volume of gas produced from 3 mole Li at 
volume of H2=33.6 litre
I am assuming that the apparatus you're referring to would be a container wherein there is water placed inside. To answer your question, I expect the water level to rise when it's placed in warm water and I expect it to fall when placed in cool water. This is because the water molecules get excited when placed in water molecule, thus, moving with more kinetic energy. The opposite goes with cool water.
15.9 grams is the amount of copper sulfate this reaction will produce.
Given:
- The reaction between copper and sulfur:

- 12.7 grams of copper completely reacts with 3.2 grams of sulfur to give copper sulfide.
To find:
The mass of copper sulfide produced
Solution
Mass of copper used by the scientist = 12.7 g
Mass of sulfur used by the scientist = 3.2 g
Mass of copper sulfide this reaction will produce. =?
According to the law of conservation of mass:
Total mass of reactants = Total mass of products
The total mass of reactants in the reaction = R = 12.7 g + 3.2 g = 15.9 g
The total mass of product formed in the reaction = P
P = R = 15.9 g
Mass of copper sulfide this reaction will produce = 15.9 g
15.9 grams is the amount of copper sulfate this reaction will produce.
Learn more about the law of conservation of mass:
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