The particals in a physical change alwayd stay the same, but for a chemical change that is the only time they will change. Not during a physical change
Answer:
21 kJ
Step-by-step explanation:
The formula for the heat q is
q = mCΔT
<em>Data:
</em>
m = 200 g; C = 4.184 J·°C⁻¹g⁻¹
T₁ = 50. °C; T₂ = 25 °C
<em>Calculations:
</em>
ΔT = T₂ - T₁
ΔT = 25 – 50.
ΔT = -25 °C
q = 200 × 4.184 × (-25)
q = -21 000 J Convert to kilojoules
q = -21 kJ
The negative sign shows that energy is released, so the water has released 21 kJ of energy.
I would say its option number 2 and since its an ''ion'' it would be written as H3O+ :)
The valency of nitride and magnesium is incorrect