Which kind of heat transfer does wind represent?

If a radioactive isotope has a half-life of 26.5 days, how many days does it take for a sample of the isotope to decrease by 35.

dangina [55]

Answer:

16.5 days

Explanation:

Given that:

Half life = 26.5 days

$t_{1/2}=\frac {ln\ 2}{k}$

Where, k is rate constant

So,

$k=\frac {ln\ 2}{t_{1/2}}$

$k=\frac {ln\ 2}{26.5}\ days^{-1}$

The rate constant, k = 0.02616 days⁻¹

Using integrated rate law for first order kinetics as:

$[A_t]=[A_0]e^{-kt}$

Where,

$[A_t]$ is the concentration at time t

$[A_0]$ is the initial concentration

Given:

35.0 % is decomposed which means that 0.35 of $[A_0]$ is decomposed. So,

$\frac {[A_t]}{[A_0]}$ = 1 - 0.35 = 0.65

t = 7.8 min

$\frac {[A_t]}{[A_0]}=e^{-k\times t}$

$0.65=e^{-0.02616\times t}$

t = 16.5 days.

7 0

4 years ago

Why do we have different blocks on the periodic table?

DerKrebs [107]

We have different blocks because of the different groups. One way to group elements is by element blocks, sometimes known as element families. Element blocks are distinct from periods and groups because they were developed based on a very different way of categorizing atoms.

8 0

3 years ago

Choose the pair of substances that are most likely to form a homogeneous solution.

oksano4ka [1.4K]

Answer is: a. c6h14 and c10h20.
This pair will most likely form a homogeneous solution because they are both nonpolar substances and "like dissolves like".
Other pairs will not form homogeneous solution because nonpolar substances have low solubility in polar or ionic substances (for example LiBr is ionic and C₅H₁₂ is nonpolar).

7 0

3 years ago

Read 2 more answers

Cytochromes are critical participants in the electron transport chains used in photosynthesis and cellular respiration. How do c

goblinko [34]

Answer:

4) Each cytochrome has an iron‑containing heme group that accepts electrons and then donates the electrons to a more electronegative substance.

Explanation:

The cytochromes are proteins that contain heme prosthetic groups. Cytochromes undergo oxidation and reduction through loss or gain of a single electron by the iron atom in the heme of the cytochrome:

$Cytochrome-Fe²⁺ ⇄ cytochrome-Fe³⁺-e⁻$

The reduced form of ubiquinone (QH₂), an extraordinarily mobile transporter, transfers electrons to cytochrome reductase, a complex that contains cytochromes b and c₁, and a Fe-S center. This second complex reduces cytochrome c, a water-soluble membrane peripheral protein. Cytochrome c, like ubiquinone (Q), is a mobile electron transporter, which is transferred to cytochrome oxidase. This third complex contains the cytochromes a, a₃ and two copper ions. Heme iron and a copper ion of this oxidase transfer electrons to O₂, as the last acceptor, to form water.

Each transporter "downstream" is more electronegative than its neighbor "upstream"; oxygen is located in the inferior part of the chain. Thus, the electrons fall in an energetic gradient in the electron chain transport to a more stable localization in the electronegative oxygen atom.

7 0

3 years ago

Question 7 5 pts Which of these describes the property of being a thermal insulator?

allochka39001 [22]

One of the properties of thermal insulators is that it does not conduct heat easily.

<h3>What is thermal insulation?</h3>

The process of reducing heat transfer between objects in thermal contact or a range of radiative influence is known as thermal insulation.

To get lower system thermal conductivity, low thermal conductivity materials are used to create thermal insulations.

In addition to using the right product forms and materials, specially engineered technologies or processes can also be used to provide thermal insulation.

<h3>What are the properties of a good thermal insulator?</h3>

The properties that make a good thermal insulator are

Low thermal conductivity

High resistance to heat

Should be made using thermo-insulating materials

High air permeability

Thus, the property of a good thermal insulator is that it doesn't conduct heat easily

Disclaimer: The question was given incomplete on the portal. Here is the complete question

Question: Which of these describes the property of being a thermal insulator?

answer choices

lustrous

does not conduct heat easily

malleable

has a low specific heat capacity

Learn more about insulators:

brainly.com/question/14630058

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8 0

2 years ago