Gold has a very high density of about 19.32g/cm^3 while Aluminum has a low density of 2.7 gm/cm^3 which means gold can pack more amount of matter in a comparatively small space as compared to Aluminum.
Bicarbonate, sodium, potassium
are regulated by the kidneys.
<u>Answer:</u> The number of gold atoms per cubic centimeters in the given alloy is 
<u>Explanation:</u>
To calculate the number of gold atoms per cubic centimeters for te given silver-gold alloy, we use the equation:
where,
= number of gold atoms per cubic centimeters
= Avogadro's number = 
= Mass percent of gold in the alloy = 42 %
= Density of pure gold = 
= Density of pure silver = 
= molar mass of gold = 196.97 g/mol
Putting values in above equation, we get:
Hence, the number of gold atoms per cubic centimeters in the given alloy 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)
