Which changes increase the rate of reaction between calcium
hydrochloric acid?
carbonate and dilute
1
2
3
increasing the concentration of the acid
increasing the temperature
increasing the size of the pieces of calcium carbonate

1. Increasing the concentration of the acid

2. Increasing the temperature

Explanation:

CaCO₃ + 2HCl ⟶ CaCl₂ + H₂O + CO₂

Increasing the concentration of the acid increases the number of hydronium ions in contact with the surface of the CaCO₃ per unit time.

Increasing the temperature increases the kinetic energy of the hydronium ions, so they hit the surface of the CaCO₃ mor frequently and with greater force.

3. is wrong. The bigger the pieces, the smaller the surface area that is available for reaction.

answer: enthalpy

explanation:

for a exothermic reaction, the energy is released i.e. the energy of the products is lower than the energy of the reactants.

= enthaply

= energy of products

= energy of reactants

as , thus comes out to be negative. negative value of enthalpy shows that the reaction is exothermic.

it can be observed without changing the identity of the object.

it depends on what substance you're talking about as well as many other factors. in quantum mechanics, the observation of particles affects the observers ability to measure certain properties. for example: you can know the velocity of a particle, but you can't know it's position; or you can know it's position, but not it's velocity. it's like trying to find out where a grain of sand is by throwing other grains of sand at it. once you find out where it is, it's been moved. it's also like trying to find an answer to the question of whether or not a tree falling in a forest makes a sound if nobody is there to hear it. paradoxically, the only way to find out is to be there and hear it.