Balancing of chemical equation is essential because of the law of conservation of mass, which states that the mass of a system can not be created or removed.

The second equation is balanced

$2KCl_(_a_q_) +Pb(NO_3)_2_(_a_q_) ==> 2KNO_3_(-a_q_) + PbCl_2(_a_q_)$

This is because the number of elements of each atom in the product side equal the number of elements of each atom on the reactant side.

The first equation is not balanced

$H_2SO_4 _(_a_q) + 2Al_(_s_) ==> Al(SO_4)_3_(_a_q_) + H_2_(_g_)$

This is because there is 1 molecule of $SO_4^{-2}$ on reactant side as compared to 3 molecules of $SO_4^{-2}$

To balance the equation we add a coefficient of 3 on sulphuric acid ( $H_2SO_4$ ) and a coefficient of 3 on hydrogen ( $H_2$ )

$3H_2SO_4_(_a_q_) + 2Al_(_s_) ==> Al(SO_4)_3_(_a_q_) + 3H_2_(_g_)$

7 0

4 years ago

Are all single bonds sigma bonds?

Nikolay [14]

Single bonds are those that bond with one atom, and sigma bonds are the strongest type of covalent bonds that are single bonded.

That means NO, not all single bonds are sigma bond, but all sigma bonds are single bonds.

6 0

3 years ago

When the electron from the n=4 excited state drops to the ground state, does it absorb energy or emit energy?

zubka84 [21]

Answer:

It emits energy since to move from a higher energy level to a lower energy level or ground state, it must lose energy.

3 0

3 years ago