if density = m(mass) / v(volume) then the answer would be 3
Answer:
Explanation:
<u>1. Convert Grams to Moles</u>
Use the molar mass (found on the Periodic Table) to convert from grams to moles.
Use this value as a ratio.
Multiply by the given number of grams.
Flip the ratio so the grams of boron cancel out.
<u>2. Convert Moles to Atoms</u>
We use Avogadro's Number, 6.02*10²³: the number of particles (atoms, molecules, etc.) in 1 mole of a substance. In this case, the particles are atoms of boron.
Multiply by the number of moles we calculated.
The moles of boron cancel.
The original value of grams has 4 significant figures, so our answer should have the same. For the number we calculated, that is the thousandth place.
The 6 tells us to round the 2 to a 3.
25.00 grams of boron is equal to 1.393*10²⁴ atoms.
Answer:A) It was developed from past observations- true
It is subject to experimentation and revision.- false
It explains why mass is conserved- false
It predicts future observations-true
Explanation:
Before a hypothesis is proclaimed to be a law in science, numerous observation must have confirmed its validity and rigorous experimentation under carefully controlled conditions usually precedes the acceptance of a hypothesis as a law. The law of conservation of mass was developed from numerous past observation that proved its validity.
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)
