Answer:
The ratio of the amounts of U 238 and Pb 206 in a rock sample enables the age of the rock to be estimated using the technique of radiometric dating. It moves back in the periodic table until the isotope falls in the band of stability at Pb 206.
Answer:
1= Ionic compounds
2= Covalent compounds
Explanation:
Ionic bond:
It is the bond which is formed by the transfer of electron from one atom to the atom of another element.
Both bonded atoms have very large electronegativity difference. The atom with large electronegativity value accept the electron from other with smaller value of electronegativity.
For example:
Sodium chloride is ionic compound. The electronegativity of chlorine is 3.16 and for sodium is 0.93. There is large difference is present. That's why electron from sodium is transfer to the chlorine. Sodium becomes positive and chlorine becomes negative ion.
Covalent bond:
It is formed by the sharing of electron pair between bonded atoms.
The atom with larger electronegativity attract the electron pair more towards it self and becomes partial negative while the other atom becomes partial positive.
For example:
In water the electronegativity of oxygen is 3.44 and hydrogen is 2.2. That's why electron pair attracted more towards oxygen, thus oxygen becomes partial negative and hydrogen becomes partial negative.
Answer : The volume of solution will be 2.96 liters.
Explanation :
Molarity : It is defined as the number of moles of solute present in one liter of volume of solution.
Formula used :
In this question, the solute is NaF.
Now put all the given values in this formula, we get:
Therefore, the volume of solution will be 2.96 liters.
A. dose
a dose is an amount, a response is an action, and pollutant and toxins are substances
The enthalpy of reaction for the decomposition of calcium carbonate is 177.4 KJ/mole .
We know that the enthalpy of reaction can be obtained from the enthalpy of formation of the reactants and that of the products using the formula;
ΔHrxn = ΔHf (products) - ΔHf (reactants)
The heat of formation of the species are as follows;
ΔHf (CaCO3(s)) = −1206.9 KJ/mol
ΔHf (CaO(s)) = - 636 KJ/mole
ΔHf (CO2(g)) = -393.5 KJ/mole
ΔHrxn = [( -393.5 KJ/mole ) + ( - 636 KJ/mole)] - [ −1206.9 KJ/mol]
ΔHrxn = 177.4 KJ/mole
Learn more: brainly.com/question/13164491