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ValentinkaMS [17]
3 years ago
8

A zircon mineral is found in the North Cascades and used to date the age of the mountains. The sample is treated and the relativ

e amount of 235U and 207Pb are evaluated by mass spectroscopy. The number of atoms found are:
Chemistry
1 answer:
Gre4nikov [31]3 years ago
6 0

Answer:

756.6 years.

Explanation:

Carbon dating is the process of measuring carbon - 13 of a dead object or substance in order to determine the age of the object or substance. This question is about radionuclide dating. The number of nuclei in a radioactive substance disintegrate in a decreasing exponentially manner with time.

In order to determine the age of the North Cascades we will be using the formula below;

Age, t= 1/ λ × [ ln (1 + Dt/pt). ---------(1).

Also, λ = ln 2/ t(1/2).

Where t(1/2) is the half life, Dt and pt are the numbers of daughter atoms and the numbers of parent atoms respectively. The assumption is that there are no daughter atoms initially at time, t= 0 and daughter atoms are due to the parent atoms decay.

Hence, λ = ln 2 / 10.= 0.69315/10 = 0.07 yr^-.

So, using equation (1) above we will have;

Age,t = 1/ 0.07 [ ln (1 + 3.93 × 10^11/ 4.15 × 10^12) ].

Age, t = 14.3 [ ln (1 + 9.5 ×10^22)].

Age, t= 14.3 × 52.91.

Age,t = 756.6 years

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What volume is needed to store 0.80 moles of helium gas at 204.6 kpa and 300 k?
shepuryov [24]
Answer is: 9,7 L is needed to store helium gas.
n(He) = 0,80 mol.
p(He) = 204,6 kPa.
T = 300 K.
R = 8,314 J/K·mol; universal gas constant.
Use ideal law eqaution: p·V = n·R·T.
V = n·R·T / p.
V(He) = 0,80 mol · 8,314 J/K·mol · 300 K ÷ 204,6 kPa.
V(He) = 9,75 L.


3 0
3 years ago
Does adding 1 mol of NaCl to 1 kg of water lower the vapor pressure of water to the same extent, a lesser extent, or a greater e
igor_vitrenko [27]

Answer:

Adding 1 mol of NaCl to 1 kg of water lower the vapor pressure of water <em><u>to the same extent</u></em>  by adding 1 mol of C_06H_{12}O_6 to 1 kg of water.

Explanation:

1) Moles of NaCl ,n_1=1 mol

Mass of water = m= 1 kg = 1000 g

Moles of water = n_2=\frac{1000 g}{18 g/mol}=55.55 mol

Vapor pressure of the solution = p

Vapor pressure of the pure solvent that is water = p_o=17.5 Torr

Mole fraction of solute(NaCl)= \chi_1=\frac{n_1}{n_1+n_2}

\frac{p_o-p}{p_o}=\frac{n_1}{n_1+n_2}

\frac{17.5 Torr-p}{17.5 Torr}=\frac{1 mol}{1 mol+55.55 mol}

p=17.19 Torr

The vapor pressure for the NaCl solution at 17.19 Torr.

2) Moles of sucrose ,n_1=1mol

Mass of water = m  = 1 kg = 1000 g

Moles of water = n_2=\frac{1000 g}{18 g/mol}=55.55 mol

Vapor pressure of the solution = p'

Vapor pressure of the pure solvent that is water = p_o=17.5 Torr

Mole fraction of solute ( glucose)= \chi_1=\frac{n_1}{n_1+n_2}

\frac{p_o-p}{p_o}=\frac{n_1}{n_1+n_2}

\frac{17.5 Torr-p}{17.5 Torr}=\frac{1 mol}{1 mol+55.55 mol}

p'=17.19 Torr

The vapor pressure for the glucose solution at 17.19 Torr.

p = p' = 17.19 Torr

Adding 1 mol of NaCl to 1 kg of water lower the vapor pressure of water to the same extent  by adding 1 mol of C_06H_{12}O_6 to 1 kg of water.

3 0
3 years ago
A light bulb has a resistance of 96.8 Ω. What current flows through the bulb when it is connected to a 120 V source of electrica
Finger [1]

Answer:

I = 1.23 A

Explanation:

Given that,

The resistance of the lightbulb, R = 96.8 Ω

Voltage, V = 120 V

We need to find the current flows through the lightbulb. Let the current be I. We can use the ohm's law to find it i.e.

V=IR\\\\I=\dfrac{V}{R}\\\\I=\dfrac{120}{96.8}\\\\I=1.23\ A

So, the current flows through the bulb is 1.23 A.

8 0
3 years ago
At 9 a.m. on May 21, a body is discovered near a path in a park. The body is 10 feet from a tree beside the path. The body is pa
katrin2010 [14]

I'm pretty sure its D, Time of discovery of the body. Let me know (:

4 0
3 years ago
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Why does a patch of garbage in the ocean effect humans on land

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