Answer: B represents an element.
a) When the reaction takes place a yellow precipitate will be formed.
b) The law of conservation of mass is true.
<u>Explanation:</u>
a) When a lead nitrate solution is mixed with a potassium chromate solution, a yellow precipitate containing lead forms according to the equation:
→ 
b) Law of conservation of mass for the given reaction is true.
From the given table we know the mass of reactants and its products.
Law of conservation of mass is a principle when a reaction takes place in a closed system, the mass of the products and reactants in the system doesn't change.
⇒The sum of the mass of the reactants = The sum of the mass of the products.
The sum of the reactants = 128.71+128.97.
= 257.68 g.
The sum of the products = 154.10+103.58.
= 257.68 g.
Thus law of conservation of mass is true for the above reaction.
MgH2 + 2 H2O → Mg(OH)2 + 2 H2
Orbital
All atoms have the same number of electrons as protons. Negative electrons are attracted to the positive nucleus. This force of attraction keeps electrons constantly moving around the nucleus. The region where an electron is most likely to be found is called an orbital.
Here you go :)
Answer:
184.62 ml
Explanation:
Let
and
be the initial and
and
be the final pressure, volume, and temperature of the gas respectively.
Given that the pressure remains constant, so
...(i)
= 200 ml
K
K
From the ideal gas equation, pv=mRT
Where p is the pressure, v is the volume, T is the temperature in Kelvin, m is the mass of air in kg, R is the specific gas constant.
For the initial condition,

For the final condition,

Equating equation (i), and (ii)

[from equation (i)]

Putting all the given values, we have

Hence, the volume of the gas at 3 degrees Celsius is 184.62 ml.