Answer: The 
for the given chemical reaction is -175.51 kJ/mol
Explanation: Enthalpy change of the reaction is defined as the amount of heat released or absorbed in a given chemical reaction.
Mathematically,
We are given a chemical reaction. The reaction follows:
Enthalpy change for the reaction of he given chemical reaction is given by:
Putting the values in above equation, we get
When we say decrease in boiling point, that means, we achieve boiling at a more lower temperature (lower than 100deg C). This is due to the lower atmospheric pressure. Boiling happens when the vapor pressure is equal the atmospheric pressure. Lower atmospheric pressure takes lower temperature for vapor pressure to equate with the atmospheric pressure. The answer here is letter B.
At higher elevations, it would take longer to hard boil an egg, because there is a lower boiling point, so the egg is boiling in water at a lower temperature.
(~26grams/mole) and Avogadros # (6.022x10^23) 84.3grams x 1mole/26grams x 6.022x10^23 molecules/mole = 1.95x10^24 molecules of C2H2
Answer:
Fe
Explanation:
The electrical conductivity depends mainly on the type of chemical bonds between the atoms of a compound.
In the case of MgF2, FeCl3 and FeO3, these have the type of ionic bond. This means that in the atoms of the compound there is an electron transfer, to keep eight electrons in the outermost layer and thus resemble the electronic configuration of the inert gas closest to each of the two elements, due to this ions of opposite charges are formed that are held together by electrostatic forces. These types of compounds are good conductors of electricity, however, to have this property, they must be dissolved in water or molten.
In the case of Fe, however, the type of union between atoms is metallic. In this type of junction, valence electrons are quite free inside the metal, which makes it easy for them to move. For this reason, this compound will conduct electricity in a solid state.
Explanation:
Half life is simply the amount of time it takes for half of a substance to decompose.
Options;
- Carbon-14 has a half-life of 5,730 years. A 30 gram sample will be 10 grams after 5,730 years. This is incorrect. After 5730 years, 15g of the sample ought to remain.
- Nickel-59 has a half-life of 76,000 years. A sample would go through 3 half-lives in 228,000 years. This is correct. 3 * 76000 = 228,000
- Hafnium-182 has a half-life of 9 million years. A 38 gram sample would be 4.75 grams in 27 million years. This is incorrect. Mass after 3 half lives (27/9) = 9.5 (38 / 2 / 2)
- Iron-60 has a half-life of 1.5 million years. In 6 million years a 40 gram sample would be reduced to 10 grams. This is incorrect. Mass after 4 half lives (6 / 1.5) = 2.5 gram (40 / 2 / 2 /2 / 2)
- Lead-202 has a half-life of 52,500 years. The original sample must have been 120 grams if you have a 60 gram sample after 105,000 years. This is incorrect. Original sampe = 240 gram. So after 2 half lives (105,000/52500), mass left = 60 (240 / 2 /2)
