An archaeologist discovered some charcoal at an excavation site. He sent the samples to a lab for C-14 dating, knowing that the half-life of C-14 is approximately 5,600 years. The lab reported that the charcoal had 1/8 the amount of C-14 in it that a living sample would have. How many years oldwas the charcoal?
A. 700 years
B. 1,867 years
C. 8,400 years
D. 16,800 years
E. 44,800 years

Answers

Answer 1

Answer: here we assume that disintegration has occur so the normal t½ formular will not be used
mathematically we..⅛×5600 =700
therefore it is about 700years option A

Related Questions

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The two objects shown are made of the same element. What else is true ofboth objects?A. They have the same shape.B. They are made of only one kind of atom.c. They have the same number of atoms.D. They have the same mass.
Which substance can not be broken down by a chemical change?A) methane B) propanal C) tungsten D) water

Select all that apply. The requirements for one type of atom to substitute for another in a solid solution are:a. All substitutions must be limited to the same element.
b. An atom must be identical in size.
c. An atom must be similar in size.
d. The substituting atom must be from the same period. E) The substituting atom must be from the same group.

Answers

The correct answer is options c and e.

A solid solution is basically a multi-component framework that comprises a mixture of two or more elements exhibiting a similar crystal lattice. The examples of solid solutions are alloys.

The requirements for one kind of atom to substitute for another in a solid solution are:

1. The size of the atom must be similar.

2. The substituting atom must be from a similar group.

Answer:

An atom must be similar in size.

The substituting atom must be from the same group.

Explanation:

A solid solution is a solid mixture containing a minor component uniformly distributed within the crystal lattice of another component called the major component. Metal alloys are typical examples of a solid solution.

Note that only atoms of similar size can substitute each other in a solid solution. Usually atoms of elements in the same group have atomic sizes that vary within narrow ranges. Hence atoms of elements in the same group have similar atomic sizes and can substitute each other in a solid solution.

A solution of H2SO4(aq) with a molal concentration of 4.80 m has a density of 1.249 g/mL. What is the molar concentration of this solution?

Answers

Imagine we have mass of solvent 1kg (1000g)
According to that: $molality =n(solute) / m(solvent) =\ \textgreater \ 4.8m = 4.8mole / 1kg$
= 4.8 mole * 98 g/mole = 470g
$m(H2SO4) = n(H2SO4)*Mr(H2SO4) =\ \textgreater \$ $=\ \textgreater \ Molarity = 4.8 mole / 1.2 L = 4 M$ m(H2SO4) which is =470g

m(solution) = m(H2SO4) + m(solvent) = 470 + 1000 = 1470 g
d(solution) = m(solution) / V(solution) =>
=> 1.249 g/mL = 1470 g / V(solution) =>
$Molarity = n(solute) / V(solution) =\ \textgreater \$

Answer: 4.078 M

Explanation:

MATCH THE FOLLOWING!!!(match each instrument with its description)

1. weather maps/satellite
2. Doppler radar
3. radiosonde
4. wind vane
5. psychrometer
__________________________________________________________________________
A. uses two thermometers; a dry and wet bulb
B. points in the direction winds are coming from
C. uses frequency waves to track particle movement
D. used to help track air masses and fronts
E. carried with a weather balloon

Answers

Answer: The correct matching sequence is:

1 -D , 2-C, 3-E, 4-B , 5-A

Explanation:

Weather maps/satellite:These are the satellites used to monitor the climate on the Earth in day and night.Like moc=vment of clouds, El Nino. La Nina ertc

Doppler radar is a system used to track the velocity or motion of the rain , storm or precipitation.It emit microwave signals to check the change in frequency of the wave due to the motion of the particles.

Radiosonde is an instrument carried away by balloon or any other means into different layers of atmosphere and sends information via radio.

Wind vane is an instrument used to show the direction of the wind. P

Psychrometer is an instrument used to measure atmospheric humidity.It consist of two thermometer that is wet bulb thermometer and dry bulb thermometer.

Match each weather instrument with its description.

weather maps/satellite - used to help track air masses and fronts
Doppler radar - uses frequency waves to track particle movement
radiosonde - carried with a weather balloon
wind vane - points in the direction winds are coming from
psychrometer - uses two thermometers; a dry and wet bulb

Why do gases take up so much space?

Answers

Gases take up so much space because the gas molecules are vibrating and moving very fast and in order to do this the molecules should as far as they could be to each other. They occur at low pressures and high temperatures where they can move freely in a container.

Which change occurs when an atom in an excitedstate returns to the ground state?
(1) Energy is emitted.
(2) Energy is absorbed.
(3) The number of electrons decreases.
(4) The number of electrons increases.

Answers

Answer: The correct option is (1).

Explanation:

Whenever an atom in an excited state returns back to its ground state the energy is emitted out in the form of the radiation and the value of energy emitted can be determined by using the expression:

$E=(hc)/(\lambda )$

Where E = Energy of the radiation in joules

h = Planck's constant = $6.63* 10^(-34) J.s$

$\lambda$ = Wavelength of the radiation in meters.

The change that occurs when an atom in an excited state returns to the ground state is that (1) energy is emitted.
It is emitted by photons in the form of light, or in some cases, heat.

Name the following chemical compound. NaBra. sodium bromite
b. niobium bromite
c. sodium bromide
d. niobium bromide

Answers

The answer is C Sodium Bromide.

Listed in Periodic Table Na is Sodium atomic number 11 and Bromine atomic number 35.

Answer:

C. Sodium Bromide

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