Answer:
0.014mol
Explanation:
Given parameters:
Mass of Na₂CO₃ = 1.5g
Unknown:
Number of moles = ?
Solution:
Number of moles of a compound is mathematically expressed as;
Number of moles =
Molar mass of Na₂CO₃ = 2(23) + 12 + 3(16) = 106g/mol
Number of moles = = 0.014mol
Answer:
1.2 × 10⁴ cal
Explanation:
Given data
We can calculate the heat released by the water () when it cools using the following expression.
where
c is the specific heat capacity of water (1 cal/g.°C)
According to the law of conservation of energy, the sum of the heat released by the water () and the heat absorbed by the reaction (
) is zero.
An electron is a negatively charged subatomic particle present in the space outside the nucleus of an atom. The loss of electron from an atom results in the formation of cation whereas gaining of electron by an atom results in the formation of anion. The cation possesses positive charge due to loss of electron and anion possesses negative charge due to gain of electron.
The neutral atom has no charge on it.
For given atomic symbols:
The atomic number of hydrogen is 1 and the given symbol has no charge that means it is in its neutral state. So, the number of electrons in is 1.
The atomic number of helium is 2 and the given symbol has no charge that means it is in its neutral state. So, the number of electrons in is 2.
The atomic number of hydrogen is 1 and the given symbol has a negative charge that represents a gain of electron. So, the number of electrons in is 2.
The atomic number of helium is 2 and the given symbol has two positive charge that represents loss of two electrons. So, the number of electrons in is 0.
Hence, has no electrons.