B. a combustion reaction involves a hydrocarbon burning with oxygen gas to produce water and carbon dioxide.
C. this is an endothermic reaction since ΔH would be positive.
3. I am pretty sure it is referring to the activation energy which is a characteristic all chemical reaction have and in a combustion reaction the spark gets the reaction over the activation energy.
4. K₂O(s)+CO₂(g)⇒K₂CO₃(s)+energy
The energy level of the reactants is higher than the energy level of the products (you can see this with energy diagrams).
5. 2HgO(s)+energy⇒2Hg(l)+O₂(g)
the energy levels of the products is higher than the energy level of the reactants. (this can also be seen with energy diagrams)
Answer:
An Element
Explanation:
Such substance cannot be an element because an element cannot be chemically disintegrated (i.e it cannot be disintegrated via chemical reaction).
Answer:
269,000
Explanation:
The distance between Proxima Centauri and the Sun, d₁₁ = 4.246 light years
The distance between Earth and the Sun, d₂ = 1.58 × 10⁻⁵ light years
The ratio of the distances are;
d₁/d₂ = 4.246/(1.58 × 10⁻⁵) = 268734.177215 ≈ 269,000 times
Therefore, Proxima Centauri is approximately 269,000 times further from the Sun than the Earth is from the Sun
