Answer:
(a) 1s2 2s1
Explanation:
Electron configurations of atoms are in their ground state when the electrons completely fill each orbital before starting to fill the next orbital.
<h3><u>
Understanding the notation</u></h3>
It's important to know how to read and interpret the notation.
For example, the first part of option (a) says "1s2"
- The "1" means the first level or shell
- The "s" means in an s-orbital
- The "2" means there are 2 electrons in that orbital
<h3><u>
</u></h3><h3><u>
Other things to know about electron orbitals</u></h3>
It important to know which orbitals are in each shell:
- In level 1, there is only an s-orbital
- In level 2, there is an s-orbital and a p-orbital
- in level 3, there is an s-orbital, a p-orbital, and a d-orbital <em>(things get a little tricky when the d-orbitals get involved, but this problem is checking on the basic concept -- not the higher level trickery)</em>
So, it's also important to know how many electrons can be in each orbital in order to know if they are full or not. The electrons should fill up these orbitals for each level, in this order:
- s-orbitals can hold 2
- p-orbitals can hold 6
- d-orbitals can hold 10 <em>(but again, that's beyond the scope of this problem)</em>
<h3><u>
Examining how the electrons are filling the orbitals</u></h3>
<u>For option (a):</u>
- the 1s orbital is filled with 2, and
- the 2s orbital has a single electron in it with no other orbitals involved.
This is in it's ground state.
<u>For option (b):</u>
- the 1s orbital is filled with 2,
- the 2s orbital is filled with 2,
- the 2p orbital has 5 (short of a full 6), and
- the 3s orbital has a single electron in it.
Because the 3s orbital has an electron, but the lower 2p before it isn't full. This is NOT in it's ground state.
<u>For option (c):</u>
- the 1s orbital is filled with 2,
- the 2s orbital has 1 (short of a full 2), and
- the 2p orbital is filled with 6
Although the 2p orbital is full, since the 2s orbital before it was not yet full, this is NOT in it's ground state.
<u>For option (d):</u>
- the 1s orbital has 1 (short of a full 2), and
- the 2s orbital is filled with 2
Again, despite that the final orbital (in this case, the 2s orbital), is full, since the 1s orbital before it was not yet full, this is NOT in it's ground state.
Answer:
The molecular formula is C3H6
Explanation:
Step 1: Data given
Suppose the compound has a mass of 100 grams
The compound contains:
85.63 % C = 85.63 grams C
14.37 % H = 14.37 grams H
Molar mass C = 12.01 g/mol
Molar mass H = 1.01 g/mol
Step 2: Calculate moles
Moles = grams / molar mass
Moles C = 85.63 grams / 12.01 g/mol
Moles C = 7.130 moles
Moles H = 14.37 grams / 1.01 g/mol
Moles H = 14.2 moles
Step 3: Calculate the mol ratio
We divide by the smallest amount of moles
C: 7.130 moles / 7.130 moles = 1
H = 14.2 moles / 7.130 moles = 2
The empirical formula is CH2
The molar mass of CH2 = 14 g/mol
Step 4: Calculate molecular formula
We have to multiply the empirical formula by n
n = 42 / 14 = 3
n*(CH2) = C3H6
The molecular formula is C3H6
Answer is: heat energy.
Braking is the process of controlling the velocity of an object (in this example bicycle) by inhibiting its motion.
Mechanical energy can be either kinetic or potential energy and has to do with the energy of position and motion of an object.
Kinetic energy is energy of the speed of an object and how much mass it has; basically how the object is moving.
Potential energy is type of energy is stored energy; it can be increased by getting into a higher position and/or stretching an object such as a rubber band.
A mechanical brake applies a friction force to convert the kinetic energy of the bicycle into heat energy which then dissipates into the atmosphere.
Answer:
23 g of Zn will produce 0.352 mole of zinc chloride.
Explanation:
Given data:
mass of Zn = 23 g
Moles of ZnCl = ?
Solution:
Chemical equation:
2Zn + CuCl₂ → 2ZnCl + Cu
Number of moles of Zn:
<em>Number of moles of Zn = mass/ molar mass</em>
Number of moles of Zn = 23 g / 65.38 g/mol
Number of moles of Zn = 0.352 mol
now we will compare the moles of ZnCl with Zn because it is limiting reactant.
Zn : ZnCl
2 : 2
0.352 : 0.352
So 23 g of Zn will produce 0.352 mole of zinc chloride.
