Answer:
Explanation:
Molar mass of Argon
= 35.96755 x .00337 + 37.96272 x .00063 + 39.96240 x .99600
= .12121 + .0239165 + 39.80255
= 39.95
Molar mass of silicon
27.97693 x .9223 + 28.97649 x .0467 + 29.97376 x .0310
= 25.803 + 1.35320 + .929
= 28.08
b )
No of atoms of Si in 78.2 g = 78.2 x 6.02 x 10²³ / 28.08
= 16.76 x 10²³ .
c )
42 Ar / 40 Ar = 1.05006
42 Ar / 39.95 = 1.05006
42Ar = 41.95
2 )
C₁₆H₁₅F₂N₃O₄S
Mol weight = 16 x 12 + 1 x 15 + 2 x 19 + 3 x 14 + 4 x 16 + 32
= 192 + 15 + 38 + 42 + 64+ 32
= 383
No of molecules = .078 x 6.02 x 10²³ / 383
= 1.226 x 10²⁰ molecules .
Answer:
not sure if this is the right way to answer this question but PbS is Phosphate-buffered saline (i think)
Explanation:
In rubidium oxide - Rb₂O , the ions are Rb⁺ and O²⁻
Rb is a group one element with one valence electron. To become stable it loses its outer electron to gain a complete outer shell.
Electronic configuration of Rb is - 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 5s¹
Once it loses its valence electron the configuration is;
- 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶
The noble gas with this configuration is Krypton - Kr
Oxygen electron configuration is 1s² 2s² 2p⁴
Once it gains 2 electrons the configuration is - 1s² 2s² 3p⁶
The noble gas with this configuration is Neon - Ne
Answer:
B) exothermic.
Explanation:
Hello!
In this case, we need to keep in mind that exothermic reactions release heat, so they increase the temperature as the final energy is less than the initial energy; in contrast, endothermic reactions absorb heat, so they decrease the temperature as the final energy is greater than the initial energy.
In such a way, when a dissolution process shows off a negative enthalpy of dissolution, we infer it is an exothermic process due to the aforementioned; therefore, the answer is:
B) exothermic
.
Best regards!
If the moon did not rotate we would see all hemispheres of the moon as it revolves around the Earth and not just the phases.
