Answer:
<h2>Volume = 9.29 mL</h2>
Explanation:
Density of a substance can be found by using the formula

From the question
Density = 11.3 g/mL
mass = 105 g
Substitute the values into the above formula and solve for the volume
That's

Cross multiply
11.3v = 105
Divide both sides by 11.3

v = 9.29203
We have the final answer as
<h3>Volume = 9.29 mL</h3>
Hope this helps you
Answer:

Explanation:
We already know that the mass number of an atom is the sum of the number of protons and the number of neutrons.
So, the mass number of this isotope is;
Number of protons = 7
Number of neutrons = 8
Mass number = 7 + 8 = 15
Hence, the isotope is;

Answer:
The shape of the BF3 molecule is best described as trigonal planar.
Explanation:
The Lewis Structure for BF3 is like this:
_ _
| F | | F |
\ /
B
|
| F |
---
It forms three angles of 120° each. The bonds are in the same planar that's why it is trigonal planar and they are exactly the same.
Boron and Fluorine have 3 covalent bonds, produced by electronic promotion that enables the 2py and 2pz orbitals, leaving an electron to pair in the 2px. So boron will have 3 possible electrons to pair in 2s1, 2px and 2py, remember that electronic configuration for B is 1s2, 2s2, 2p1
By hybridization between the orbitals 2s2 and 2p1, the electrons of F, can joined to make the covalent bond. The new B configuration is 1s2, 2s1, 2px1, 2py1 (these last three, hybrid orbitals)