Polylactic acid is the correct answer
Answer: A. Limestone rocks dissolving in water
Explanation:
B: This is a physical change; it changes an object physically rather than chemically. It does not change the composition of the concrete, only the shape.
C: This is also a physical change because the water is just dragging sand with it, but not actually changing the composition of it.
D: Similar to option B, this is an example of physical weathering because the ice only divides the rock into different parts but doesn't change the composition or complexity of it.
As temperature increases, the average kinetic energy of a sample of gas molecules decreases.
Answer:
A.
A chemical reaction was producing a new substance.
Explanation:
Equation of the reaction
NaOH + HCl --> NaCl + H2O
Heat of neutralization is the amount of heat evolved when one mole of acid reacts with one mole of an alkaline to form one mole of water.
When a neutralisation reaction is carried out, there is an exothermic change; energy released into the surroundings therefore since heat is given out which is what is felt.
The solute is sodium chloride seeing as it is being dissolved. The solvent would be water.
