Half-life is defined as the amount of time it takes a given quantity to decrease to half of its initial value. The equation to describe the decay is
Nt=N0(1/2)
where N0 is the initial quantity, Nt is the remaining quantity after time t, t1/2 is the half-time. So work out the equation, t1/2 = t (-ln2)/ln(Nt/N0) = 11.5*(-ln2)/ln(12.5/100) = 3.83 days
Answer:
The correct answer is option D.
Explanation:
Rate of the reaction is a change in the concentration of any one of the reactant or product per unit time.
Rate of the reaction:
Rate of decrease in nitrogen dioxide concentration is equal to the rate of decrease in carbon monoxide.
Given rate expression of the reaction:
Rate of the reaction on doubling concentration of nitrogen dioxide and carbon monoxide : R'
Doubling the concentrations of nitrogen dioxide and carbon monoxide simultaneously will increase the rate of the reaction by a factor of eight.
Hence, none of the given statements are true.
It has to be D. the time needed to boil the water decreased
Leah's experiment:
A. Takes careful and regular measurements (she measures the growth every day)
B. Has a specific hypothesis and a controlled experiment (the music is the only changing variable, the growth conditions are identical, and this is what she wants to test in her hypothesis)
C. Experimental data that can be recorded and analyzed (measuring the growth of plant fits this)
So the answer must be D, since there is no mention of past research that scientists have found on this topic.
Hello!
Elements are made up of atoms, and elements combine to make compounds. Compounds are made up of molecules, and molecules are made up of atoms.
Nitrogen is an element. It could be made up of one or many atoms. A mixture is made up of compounds, so it is not the answer.
Molecules and compounds are made up of different atoms and elements, but nitrogen is not a molecule or a compound.
There is such a thing as a nitrogen atom, though.
Therefore, your answer would be 2) Atom.
I hope this helps!