Combustion is a chemical reaction that occurs between a fuel and an oxidizing agent that produces energy, usually in the form of heat and light.
Answer:
Two-third of the toxic metal, mercury comes from gold mining.
Explanation:
During gold mining small pieces of gold which are within the soil are separated with the help of mercury. Both gold and mercury are mixed and they forms amalgam. Further gold can be extracted by vaporizing the mercury, thus releasing it into air and contributing to two-third of the air pollution by human activities.
Therefore (d) gold mining is the correct answer.
Answer:
TRUE!!!!
Explanation:
Water can act as both an acid and a base in solution and undergoes autoionization, where it can be both an acid and a base to itself. When mixed with an acid, water accepts hydrogen ions and acts as a base. However, when water is mixed with a base, it donates hydrogen ions and acts like an acid.
Not my words! I hope this helps :)
Answer:
Explanation:
For a general equilibrium
aA +bB ⇔ cC + dD ,
the equilibrium constant is K = [C]^c [D]^d / [A]^a[B]^b.
Our reasoning here should be based on the fact that Q has the same expression as K, but is used when the system is not at equilibrium, and the system will react to make Q = K to attain it ( Le Chatelier´s principle ).
So with this in mind, lets answer this question.
1. False: Q can large or small but is not the value of the equilibrium constant, it will predict the side towards the equilibrium will shift to attain it.
2. False: Given the expression for the equilibrium constant, we know if K is small the concentrations of the reactants will be large compared to the equilibrium concentrations of the products.
3. False: when the value of K is large, the equilibrium concentrations of the products will be large and it will lie on the product side.
4. True: From our previous reasongs this is the true one.
5. False: If K is small, the equilibrium lies on the reactants side.
D) Physical Change, I would argue, because you can reverse this change by boiling off (evaporating) the water. But there are arguments for both physical and chemical change being what occurs.
A physical change results in a change of the material's appearance, but no new chemical products result. A chemical change involves a chemical reaction, with new substances produced as a result of the change.
