Which chemical reaction upholds the principle of the conservation of matter?(1 point)

Question

Responses

2K + MgBr → 2KBr + Mg
2K + MgBr → 2KBr + Mg

K + 2MgBr → KBr + 2Mg
K + 2MgBr → KBr + 2Mg

2K + 2MgBr → KBr + 2Mg
2K + 2MgBr → KBr + 2Mg

K + MgBr → KBr + Mg

Answer 1

The principle of conservation of matter states that matter cannot be created or destroyed in a chemical reaction. This means that the number of atoms of each element must be the same on both sides of the reaction.

To find the reaction that upholds this principle, we need to balance the equations by counting the number of atoms of each element on both sides.

1. 2K + MgBr → 2KBr + Mg

   • Left: 2 K, 1 Mg, 1 Br
   • Right: 2 K, 1 Mg, 2 Br
   • Not balanced.

2. K + 2MgBr → KBr + 2Mg

   • Left: 1 K, 2 Mg, 2 Br
   • Right: 1 K, 1 Mg, 1 Br
   • Not balanced.

3. 2K + 2MgBr → KBr + 2Mg

   • Left: 2 K, 2 Mg, 2 Br
   • Right: 1 K, 2 Mg, 1 Br
   • Not balanced.

4. K + MgBr → KBr + Mg

   • Left: 1 K, 1 Mg, 1 Br
   • Right: 1 K, 1 Mg, 1 Br
   • Balanced.

The only equation that upholds the conservation of matter (is balanced) is:

K + MgBr → KBr + Mg