Answer: The energy required to vaporize 12.5 g of liquid water is 28.2 kJ
Explanation:
Latent heat of vaporization is the amount of heat required to convert 1 gram of liquid into its vapor state without change in its temperature.
Given : The enthalpy of vaporization of water is 40.65 kJ/mol.
n = number of moles = ![\frac{\text{Mass of water}}{\text{Molar mass of water}}=\frac{12.5g}{18g/mole}=0.694mole](https://tex.z-dn.net/?f=%5Cfrac%7B%5Ctext%7BMass%20of%20water%7D%7D%7B%5Ctext%7BMolar%20mass%20of%20water%7D%7D%3D%5Cfrac%7B12.5g%7D%7B18g%2Fmole%7D%3D0.694mole)
Thus 1 mole of water requires heat = 40.65 kJ
0.694 moles of water requires heat = ![\frac{40.65}{1}\times 0.694=28.2kJ](https://tex.z-dn.net/?f=%5Cfrac%7B40.65%7D%7B1%7D%5Ctimes%200.694%3D28.2kJ)
Thus the energy required to vaporize 12.5 g of liquid water is 28.2 kJ
Answer:
3- gamma radiation
Explanation:
Hello,
In the above question, 4 of the options are related to polymerization which are
1. Synthetic polymer
2. Natural polymer
3. Condensation polymerization
4. Addition polymerization.
The first two options are types of polymer that exists while the last two are polymerization techniques.
The odd option here which is "gamma radiation" is a particle which is emitted from radioactive substances during decay. It has no mass and no charge but it is highly penetrating and dangerous to human health.
However,
Synthetic polymers are also known as man made polymers and they exist around us because they're present in materials which we use everyday. An example is polyethylene, nylon-6,6 etc
Natural polymers are compounds which are polymeric in nature (compounds catenating to form a complex molecule). Natrual occurring polymers can be found in proteins and some lipids.
When Ksp = [A2+] [S2-]
when A is the metal: Fe, Ni, Pb, and Cu
When we have [S2-] = 0.1 m and we have Ksp for each metal So by substitution in Ksp formula we can get [A2+] for each metal and compare its value with solution concentration 0.01 M, when we have a concentration more than 0.01 M So there are no sulfides precipitates
- [Fe2+] = Ksp/[S2-]
by substitution with Fe2+ Ksp value:
= 6x10^2 / 0.1
= 6x10^3 M
when [Fe2+] > 0.01 M
∴ no precipitate- [Ni2+] = Ksp /[S2-]
by sustitution with Ni Ksp value :
= 8x10^-1 / 0.1
= 8 M
When [Ni2+] > 0.01 M
∴ no precipitate-[Pb2+] = Ksp / [S2-]
by substitution with Pb Ksp value:
= 6x10^-7 / 0.1
= 6 x 10^-6 M
when [Pb2+] < 0.01 M
∴PbS will be precipited-[Cu2+] = Ksp / [S2-]
by substitution with Cu2+ Ksp value:
= 6x10^-16 / 0.1
= 6x10^-15 M
when [Cu2+] < 0.01 M
∴ CuS will be precipited∴The sulfides precipitates are CuS & PbS
1) All matter is made of atoms. Atoms are indivisible and indestructible.
2) All atoms of a given element are identical in mass and properties
3) Compounds are formed by a combination of two or more different kinds of atoms.
4) A chemical reaction is a rearrangement of atoms.
1 and 2 were proved wrong.
Answer:
No because protons determine what type of atom it is. It is protons and neutrons that account for atomic mass