The radioisotope U-238 is primarily used in dating geologic formation. This method is used for dating sediments from either a marine or playa lake environment. Because this method is used for the period between 100,000 years and 1,200,000 years before the present, it aids in bridging the gap between the carbon-14 dating method and the potassium-argon dating method.
Answer: HA + H2O ⇌ H3O+ + H- (option #4)
Explanation: Since the acid is weak you have to use a ⇌ (equilibrium) sign. Equilibrium is denoted in a chemical equation by the ⇌ symbol. Also, when any acid dissolves into water, it produces hydronium (H3O+ or H+). Therefore, the fourth chemical reaction is your answer.
The balanced chemical reaction would be:
FeS(s)+2HCl(aq)→FeCl2(s)+H2S(g)
We are given the amount of the reactants to be used for the reaction. We use these amounts. First, we determine the limiting reactant of the reaction. From the data, we can say that FeS is the limiting ad HCl is the excess reactant. We calculate as follows:
Amount of HCl used: 0.240 mol FeS x 2 mol HCl / 1 mol FeS = 0.48 mol HCl
0.646 - 0.48 = 0.166 mol HCl left
Answer:
Incomplete
Explanation:
I wouldn't say that a scientific theory is wrong.
It is the best we have at the time, based on all available knowledge .
As each new discovery is made, scientists modify the theory to fit the new knowledge.
The scientific method is a never-ending process.
