Answer:
Substances 1 and 2
Explanation:
an element only has 1 kind of atoms :3
A shared derived characteristics is usually a homologous structure, such as a backbone, that is shared by all organisms in a group.
Answer:
3,964 years.
Explanation:
- It is known that the decay of a radioactive isotope isotope obeys first order kinetics.
- Half-life time is the time needed for the reactants to be in its half concentration.
- If reactant has initial concentration [A₀], after half-life time its concentration will be ([A₀]/2).
- Also, it is clear that in first order decay the half-life time is independent of the initial concentration.
- The half-life of the element is 5,730 years.
- For, first order reactions:
<em>k = ln(2)/(t1/2) = 0.693/(t1/2).</em>
Where, k is the rate constant of the reaction.
t1/2 is the half-life of the reaction.
∴ k =0.693/(t1/2) = 0.693/(5,730 years) = 1.21 x 10⁻⁴ year⁻¹.
- Also, we have the integral law of first order reaction:
<em>kt = ln([A₀]/[A]),</em>
where, k is the rate constant of the reaction (k = 1.21 x 10⁻⁴ year⁻¹).
t is the time of the reaction (t = ??? year).
[A₀] is the initial concentration of the sample ([A₀] = 100%).
[A] is the remaining concentration of the sample ([A] = 61.9%).
∴ t = (1/k) ln([A₀]/[A]) = (1/1.21 x 10⁻⁴ year⁻¹) ln(100%/61.9%) = 3,964 years.
The correct answer is that last one
Answer: Carbon dioxide concentrations are rising mostly because of the fossil fuels that people are burning for energy.
(1)Extra greenhouse gases in our atmosphere are the main reason that Earth is getting warmer.
(2)Greenhouse gases, such as carbon dioxide (CO2) and methane, trap the Sun's heat in Earth's atmosphere.
(3)It says that the 1997 Kyoto Protocol was an unmitigated success, with every single one of the 36 countries that signed up reducing their mean annual greenhouse gas emissions from 2008-2012 by an average of 5% relative to the levels seen in 1990.Jun 15, 2016 Many argue that Kyoto's failure is due to deficiencies in the structure of the agreement, such as the exemption of developing countries from reductions requirements, or the lack of an effective emissions trading scheme.by 2012
Explanation: