Answer:
part 1
3) 5.47 molecules
4) 11.15 moles
5) 2.95 × 10^23 molecules
6) 7670.9g
part2
1) 216000g
2) 5.71 molecules
3) 0.18 moles
4) 737.40g
5) 2.89×10^23 molecules
Explanation:
part 1
3) number of moles = (6.02 × 10^23)/11.0
=5.47molecules.
4) moles= (6.02 × 10^23)/(5.40×10^23)
= 11.15 moles
5) molar mass of NH3= 14+(3×1)= 14+3=17
number of molecules= (6.02 × 10^23) × 17/35
= (6.02 × 10^23)× 0.49 =2.95 × 10^23 molecules
6) molar mass of N2I6= (2×14) + (6×127)
= 28+762= 790g/mol
mass= 790 × (6.02 × 10^23)/(6.20×10^22)
=790× 9.71= 7670.9g
part 2
1) molar mass of CuBr= 64+80= 144g/mol
mass= 1500 × 144= 216000g
2) molecules = (6.02 × 10^23)/1.055
= 5.71 molecules
3) moles = (6.02 × 10^23)/(3.35×10^24)
= 0.18 moles
4) molar mass of SiO2= 28+ (2×16)= 28+32
=60gmol
mass= 60 × (6.02 × 10^23)/(4.90×10^22)
= 60× 12.29= 737.40g
5) molar mass of CH4= 12+(4×1)= 12+4=16g/mol
number of molecules= (6.02 × 10^23) × 16/33.6
= (6.02 × 10^23)× 0.48
= 2.89×10^23 molecules
Answer: 0.4mL of the stock solution is needed
Explanation:
This is simply a dilution analysis. From the question, the following were obtained:
C1 = 25 mg/mL = 25x10^-3g/mL
V1 =?
C2 = 25 ug/mL = 25x10^-6g/mL
V2 = 400ml
Applying the dilution formula, we have:
C1V1 = C2V2
25x10^-3 x V1 = 25x10^-6 x 400
Divide both side by 25x10^-3, we have:
V1 = (25x10^-6 x 400) / 25x10^-3
V1 = 0.4mL
Therefore, 0.4mL of the stock solution need.
Data:
V1 = 6.7 liter
T1 = 23° = 23 + 273.15 K = 300.15 K
P1 = 0.98 atm
V2 = 2.7 liter
T2 = 125° = 125 + 273.15 K = 398.15 K
P2 = ?
Formula:
Combined law of ideal gases: P1 V1 / T1 = P2 V2 / T2
=> P2 = P1 V1 T2 / (T1 V2)
P2 = 0.98 atm * 6.7 liter * 398.15 K / (300.15K * 2.7 liter)
P2 = 3.22 atm
Answer:
False
Explanation: isotopes generally have the same physical and chemical properties because they have the same numbers of protons and electrons.
Band theory
The atomic orbitals of metals combine to form <em>molecular orbitals</em>. The molecular orbitals are so close in energy that they form a <em>band</em> of energies.
<em>Ionic bond theory</em> is incorrect because there are no ions in metals.
<em>Covalent bond theory</em> is incorrect because there are no covalent bonds in metals.
<em>Electron bond theory</em> is incorrect because there is no theory with that name (but there is a <em>valence bond theory</em>).
