For a reaction to occur, energy must be absorbed to break chemical bonds
<u>Explanation:</u>
Reactions can be classified as chemical reaction, nuclear reaction, thermal reaction. So in these three reaction types, the nature of energy will only be varying.
But in order to execute a reaction, there should be breaking of existing bonds and then formation of new bonds. So for breaking of the bonds of reactants, energy should be absorbed from the surrounding.
Then the extra energy will be released after forming the products. Thus, the process of absorption of energy will lead to endothermic process and the process of releasing of energy will lead to exothermic reaction. So for a reaction to occur, energy must be absorbed to break the chemical bonds.
<h2>
Answer: can see</h2>
Explanation:
The portion visible by the human eye of the electromagnetic spectrum is between 380 nm (violet-blue) and 780 nm (red) approximately. Which means this part of the spectrum is located between ultraviolet light and infrared light.
Note the fact only part of the whole electromagnetic spectrum is visible to humans is because the receptors in our eyes are only sensitive to these wavelengths.
Therefore:
<h2>The visible spectrum refers to the portion of the electromagnetic spectrum that <u>we </u><u>
can see</u></h2>
Answer:
Force of friction, f = 751.97 N
Explanation:
it is given that,
Mass of the car, m = 1100 kg
It is parked on a 4° incline. We need to find the force of friction keeping the car from sliding down the incline.
From the attached figure, it is clear that the normal and its weight is acting on the car. f is the force of friction such that it balances the x component of its weight i.e.


f = 751.97 N
So, the force of friction on the car is 751.97 N. Hence, this is the required solution.
Answer: EL ZINC ES EL ELEMENTO PURO PORQUE NO HA REACCIONADO CON NINGÚN OTRO METAL O NO METAL. EL SULFURO DE ZINC ES UN COMPUESTO PORQUE HA REACCIONADO CON EL AZUFRE PARA HACER EL COMPUESTO.
english:
ZINC IS THE PURE ELEMENT BECAUSE IT HAS NOT REACTED WITH ANY OF OTHER METAL OR NONMETAL. ZINC SULPHIDE IS A COMPOUND BECAUSE IT HAS REACTED WITH SULPHUR TO MAKE COMPOUND.
I think the answer would be C