<span>C. New substances are always produced in chemical changes, which is not the case with physical changes. For example, when you cut wood into smaller pieces you still have wood in the end. But, with a chemical change you change the substance's whole composition. For example when you add two hydrogen's to one oxygen you have water and it can't break down from that. </span><span />
Answer: The difference between an element and a compound is that an element is a pure substance that is made of only one element, but a compound is 2 or more elements together
Explanation:
Answer:
0.940mol &
0.000301mol respectively.
Explanation:
number of moles = given mass / molar mass
given mass of Nacl = 55g Molar mass = 23 + 35.5
n=m/M = 55g/58.5g/mol = 0.940mol
note- (add the atomic weights of sodium and chlorine to get the molar mass of Nacl.) = 58.5g/mol
similarly, NaCO3 = 23 + 12 + 16*3 = 83g/mol
n=m/M = 0.025g/83g/mol = 3.01 * 10^-4 = 0.000301mol
extra: If you ever get asked to put it in number of particles just use the relation of 1mole = 6.02 * 10^23 particles.
The volume of the drum after chilled quickly is 3.6 L.
<u>Explanation:</u>
As per the Charles Law, for any gas at constant pressure, volume of the gas is in direct proportion with the temperature measured in Kelvin. As the temperature increases, the gas expands and vice versa.
After chilling the drum, the volume will get reduced and it can be found as,
V2 = 
= 
= 3.6 L
Here the drum is chilled quickly, that is temperature is reduced and so the volume also decreases.
