a. Hydrogen
Hydrogen has a line at 410 nm.
Mercury has a line at 405 nm.
Sodium and neon have no lines near 412 nm.
Answer: 33%
Explanation: Because carbon atoms are only 1/3 of the compound since the other 2 atoms are oxygen. Like H20, Oxygen is one out of the three atoms in the compound.
The first thing you need to do is calculate the molar mass of C4H10. To do this, look at a periodic table for the atomic mass of carbon and hydrogen. For Hydrogen it's 1.008 amu. For Carbon its 12.01 amu. This means that a mole of hydrogen has a mass of 1.008 amu. So to calculate the molar mass of C4H10:
atomic mass of H * number of H atoms in one molecule + atomic mass of C * number of C atoms in one molecule
1.008 * 10 + 4 * 12.01
= 58.12 g
So one mole of C4H10 would have a mass of 58.12 g.
Now you were told to find the number of moles for 2.50 g, so you need to change 2.50g into moles
2.50g *1 mole/ 58.12 g = .043014 moles of C4H10
You know that for every mole of C4H10, there are 4 moles of Carbon
so
.043014 mole C4H10 * 4 mole C/1 mole C4H10 = .172 mol C
Now to find the number of atoms, use avogadros numbe5r
6.022 * 10^23 * .17 mol = 1.024 × 10^23 atoms your answer.The first thing you need to do is calculate the molar mass of C4H10. To do this, look at a periodic table for the atomic mass of carbon and hydrogen. For Hydrogen it's 1.008 amu. For Carbon its 12.01 amu. This means that a mole of hydrogen has a mass of 1.008 amu. So to calculate the molar mass of C4H10:
atomic mass of H * number of H atoms in one molecule + atomic mass of C * number of C atoms in one molecule
1.008 * 10 + 4 * 12.01
= 58.12 g
So one mole of C4H10 would have a mass of 58.12 g.
Now you were told to find the number of moles for 2.50 g, so you need to change 2.50g into moles
2.50g *1 mole/ 58.12 g = .043014 moles of C4H10
You know that for every mole of C4H10, there are 4 moles of Carbon
so
.043014 mole C4H10 * 4 mole C/1 mole C4H10 = .172 mol C
Now to find the number of atoms, use avogadros numbe5r
6.022 * 10^23 * .17 mol = 1.024 × 10^23 atoms your answer.
Hope it helps
Answer:
The valency does not change going down a group since the bonding behavior is not affected by the core electrons.
There is this thing called isotopes
it means that atoms of the same element can have a different number of neutrons.
if there is a change in the no. of neutrons, there will definitely be a change in the mass number.
so the answer is A) mass number
