A sample originally contained 1.28 g of a radioisotope. It now contains 1.12 g of its daughter isotope. How many half-lives have passed since the sample originally formed?
3
4
8
16
Answers
The relation between number of half-lives (n) and decimal amount remaining (x) can be expressed as:
We need to calculate n, but we need x to do that. To calculate what percentage of a radioactive species would be found as daughter material, we must calculate what amount remained:
1.28 - 1.12 = 0.16
If 1.28 is 100%, how much percent is 0.16:
1.28 : 100% = 0.16 : x
x = 12.5%
Presented as decimal amount:
x = 0.125
Now, let's implement this in the equation:
Because of the exponent, we will log both sides of the equation:
Therefore, 3 half-lives have passed since the sample originally formed.
Answer:
3
Explanation:
Related Questions
What will happen to the volume if the amount of a gas is decreased at constant temperature and pressure?
Read the information in the table below: Reaction A Energy to break bonds is more than energy release to form bondsB Energy to break bonds is less than energy release to form bonds Which type of reaction is represented by B? Endothermic reaction Exothermic reaction Reaction between liquids Reaction between solids
How much does 1.2 moles of koh weight
A chemistry teacher adds 50.0 mL of 1.50 M H2SO4 solution to 200 mL of water. What is the concentration of the final solution? A)0.300 M B)0.375 M. C)6.00 M. D)7.50 M.
happens when John rubs his hands?
O A. The skin on his hands rapidly conducts heat, similar to metal.
O B. He traps heat between his hands because skin is an insulator. IS
O C. The particles In his hands vibrate faster because of friction.
O D. Thermal energy moves from his fingertips to his palms.
O E. He simulates a fever that'll raise his core body temperature.
Answers
Answer:
Fairly certain it's C. The particles In his hands vibrate faster because of friction :)
Answer:
C
Explanation:
B. similar to other minerals
C. variable depending on where its found
D. influenced by heat and light
Answers
The chemical compositions of minerals is very necessary in order to define or describe a certain mineral. Some minerals can be written in simple chemical formula while others are also written in complicated chemical formulas.
(B) reduction
(C) deposition
(D) fission
Answers
fermentation is when organic matericals go bad and delope mold for exg,
reduction is when atoms of elements have their oxidation states changed (exg rusting)
deposition is when molecules set out in any sort of solution.
Answer: Option D) is correct which is fission
B. Solids are high in density and compressible.
C. Solids are low in density and incompressible.
D. Solids are high in density and incompressible.
Answers
Answer: Option (D) is the correct answer.
Explanation:
Solids are the substances whose molecules are closely packed together due strong inter molecular forces between them. This causes the solid to have a fixed shape and volume.
Whereas density is mass divided by per unit volume.
Mathematically, Density =
Since, density is proportional to mass. So, more is the mass that is, more is the number of molecules held together by strong forces more will be its density.
Therefore, we can conclude that the statement solids are high in density and incompressible, best describes solids.
Multiple answers could be chosen, just due to the fact that a solid is nothing more than just an object that cannot change it's physical shape into an object; just as water would. a solid can have a low density; such as paper, plastics, or even just a piece of wood.
But think of a block of ice. You can break it, and crush it. It cannot be formed into any other shape. If you did break it, it only would make more ice fragments. And it's next phase is a liquid; if it were to be melted.
Answers
Answer:
A.
Explanation:
The amount of mass always stays the same, matter cannot be created nor destroyed, it can only change forms. Thus, the answer is A.
In a chemical reaction the total mass of all the substances taking part in the reaction remains the same. Also, the number of atoms in a reaction remains the same. Mass cannot be created or destroyed in a chemical reaction.
I hope this helps..
b. is an intrusive igneous rock
c. is an organic sedimentary rock
d. forms from regional metamorphism
Answers
Granite forms when magma cools slowly underground. Granite is an intrusive igneous rock. The answer is letter B. granite is composed mostly of quartz and feldspar with minor amounts of mica, amphiboles and other minerals.