Answer:
The molar solubility of lead bromide at 298K is 0.010 mol/L.
Explanation:
In order to solve this problem, we need to use the Nernst Equaiton:
E is the cell potential at a certain instant, E⁰ is the cell potential, n is the number of electrons involved in the redox reaction, [ox] is the concentration of the oxidated specie and [red] is the concentration of the reduced specie.
At equilibrium, E = 0, therefore:
[red] = 0.010 M
The reduction will happen in the anode, therefore, the concentration of the reduced specie is equivalent to the molar solubility of lead bromide.
Answer: The moles of melatonin are 0.000043
Explanation:
According to avogadro's law, 1 mole of every substance weighs equal to its molecular mass and contains avogadro's number of particles.
To calculate the moles, we use the equation:
Given mass of melatonin = 0.01 g
Molar mass of melatonin = 232.28 g/mol
Thus the moles of melatonin in 0.01 g are 0.000043
A chemical bond that involves the transfer of electrons from a metal to a nonmetal and thus forms ions and the atoms in the molecule are attracted towards each other through electrostatic force of attraction are said be ionic bond. In short, the bond formed between the two oppositely charged ions.
In salt, the compound formed between sodium and chlorine is sodium chloride having molecular formula where sodium is a metal and chlorine is the non-metal. The formation of the compound takes place by transfer of an electron from sodium thus forming a cation of formula
to chlorine which gains electron and thus results in an anion formation having formula
. The force of attraction between these oppositely charged ions that helds them together and results in formation of
compound is electrostatic force of attraction.
Hence in salt, the nature of bond between sodium and chlorine is ionic.
Isotopes are defined as atoms of same element with different mass number and same atomic number.
Here, atomic number is equal to number of protons and number of electrons, it is denoted by symbol Z thus,
and, mass number is equal to sum of number of protons and neutrons, it is denoted by symbol A thus,
The three isotopes of tin are given, Sn-116, Sn-120 and Sn-126, mass number for these three isotopes is 116, 120 and 126 respectively. Since, they are isotopes thus, atomic number remains the same that is 50.
Since, thus, number of protons and electrons will be 50.
For Sn-116,
Or,
Or,
For Sn-120,
For Sn-126,
Therefore, mass number, number of protons, electrons and neutrons in all three isotopes are:
Sn-116:
Mass number= 116
Protons=50
neutrons=66
electrons=50
Sn-120:
Protons=50
neutrons=70
electrons=50
Sn-126:
Protons=50
neutrons=76
electrons=50