What can we tell from the column that an element is in?

In composting, gardeners allow a pile of plant material such as dead leaves to decay. Composting is a form of combustion.

maks197457 [2]

Answer:

This is true

Explanation:

Because it mixes in with the earth making the earth more suitable for gardening and/or farming.

8 0

2 years ago

The carbon-14 content of a wooden harpoon handle found in an Inuit archaeological site was found to be 61.9% of the carbon-14 co

astraxan [27]

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:

k = ln(2)/(t1/2) = 0.693/(t1/2).

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:

kt = ln([A₀]/[A]),

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.

7 0

3 years ago

Which of the following is not found in the nucleus of an atom?

Ulleksa [173]

A. electron. The nucleus has protons and neutrons, quark is the particle which forms protons and neutrons.

8 0

3 years ago

Calculate the net force 175 N 1125 N

Ket [755]

Answer:

<h3>_____________&_________</h3><h2>Net force = sum of all forces with directions</h2><h2>so.....</h2><h2>NET FORCE = 125+(-75)</h2><h2> = 50 N</h2><h2> in the direction of yellow </h2><h2> t-shirt man</h2><h2>------------------------------------</h2>

4 0

2 years ago

An iron bar at 200c is placed in thermal contact with an identical iron bar at 120c in an isolated system

Step2247 [10]

Conduction: In the conduction, the heat is transferred from the hotter body to the colder body until the temperature on both bodies are equal.

In thermal equilibrium, there is no heat transfer as the heat is transferred till the temperature on the bodies are not same.

In the given problem, an iron bar at 200°C is placed in thermal contact with an identical iron bar at 120°C in an isolated system. After 30 minutes, the thermal equilibrium is attained. Then, the temperature on both iron bars are equal.Both iron bars are at 160°C in an isolated system.

But in an open system, the temperatures of the iron bars after 30 minutes would be less than 160°C. There will be heat lost to the surrounding. The room temperature is 25°C. There will be exchange of the heat occur between the iron bars and the surrounding. But It would take more than 30 minutes for both iron bars to reach 160°C because heat would be transferred less efficiently.

7 0

2 years ago

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