Answer:
12
Explanation:
To get to this answer you have to look at the number first. So the given number is 12.47 and you need 2 sig figs.
To help you understand this more start off by underlining the first 2 numbers because 2 sig figs are needed. <u>12</u>.47
Now you want to look at the number after the underlined (I bolded that number). <u>12</u>.47
If the number is above 5 then you would round the previous number up by one but in this case it is 4 so you do not increase the number. Hence, you getting 12 as your final answer.
Hope this helped! Let me know if you have any questions.
Answer:
The metal surface becomes more positive as electrons are lost from it.
Explanation:
Let us note that photoelectric effect refers to a phenomenon in which electrons are ejected from a clean metal surface irradiated with light of appropriate frequency. This photon must possess a frequency above the threshold frequency of the metal and its energy must exceed the work function of the metal. When these conditions are met, electrons are emitted from a clean metal surface, having a constant kinetic energy as long as the frequency of the incident photon remains constant.
However, as photoelectric effect progresses and electrons are lost from the metal surface, the metal surface becomes more positive. The more positive the surface, the greater the attraction of the positive surface for the emitted electrons. This reduces the kinetic energy of the emitted photons even though the frequency of incident photons is held constant.
Answer:
1.087L
Explanation:
No of mole = concentrate × volume
Volume= 0.25/0.23 = 1.087L
Answer:
They have different amounts of neutrons.
They have different mass numbers.
Explanation:
Carbon-12 and carbon-13 are two isotopes of the element carbon. The difference between carbon-12 and carbon-13 is the number of neutrons in each atom. Atoms of both isotopes of carbon contain 6 protons. Atoms of carbon-12 have 6 neutrons, while atoms of carbon-13 contain 7 neutrons. And because the mass number is the sum of protons and neutrons in the nucleus then will be different too. Atoms of carbon-12 have the mass number equal to 12 a.m.u. while atoms of carbon-13 have the mass number equal to 13 a.m.u. .
a.m.u. - atomic mass units