Answer:The green growing on the penny of copper and the rust forming on the nail of iron are chemical changes. Boiling away salt water, scraping iron filings from a mixture of sand with a magnet, and breaking a rock with a hammer, are physical changes.
Explanation:
Hello there what is the question?
This is an incomplete question, here is a complete question.
The conversion of cyclopropane to propene occurs with a first-order rate constant of 2.42 × 10⁻² hr⁻¹. How long will it take for the concentration of cyclopropane to decrease from an initial concentration 0.080 mol/L to 0.053 mol/L?
Answer : The time taken will be, 17.0 hr
Explanation :
Expression for rate law for first order kinetics is given by:
where,
k = rate constant = 
t = time passed by the sample = ?
a = initial concentration of the reactant = 0.080 M
a - x = concentration left = 0.053 M
Now put all the given values in above equation, we get
Therefore, the time taken will be, 17.0 hr
Answer:
The temperature of a substance when the average kinetic energy of its particles increases and decreases when the average kinetic energy decreases.
Explanation:
Atoms and molecules are in constant motion. Kinetic energy is a form of energy, known as energy of motion. Kinetic energy is a form of energy, known as energy of motion. The kinetic energy of an object is that which is produced due to its movements, which depends on its mass (m) and speed (v).
Temperature refers to a quantity used to measure the kinetic energy of a system. That is, temperature is defined as an indicator of the average kinetic energy of the particles in a body.
So, since temperature is a measure of the speed with which they move, the higher the temperature the faster they move.
Finally, <u><em>the temperature of a substance when the average kinetic energy of its particles increases and decreases when the average kinetic energy decreases.</em></u>
Answer:
Exothermic
Explanation:
I think it is exothermic because heat is being released
