1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
svetlana [45]
2 years ago
11

The half-life of C-14 is 5470 years. If a particular archaeological sample has one-quarter of its original radioactivity remaini

ng,what is the best estimate for its age?
Chemistry
1 answer:
Gennadij [26K]2 years ago
3 0

Answer:

When there remains one-quarter of the sample, the age of the sample is 10940 years

Explanation:

<u>Step 1:</u> Data given

The half-life of C-14 is 5470 years.

The half- life time is the time required for a quantity to reduce to half of its initial value.

This means after 5470 years there remains half of the C-14 sample.

To remain a quarter of the sample, another cycle of 5470 years is required.

This means 2 half-lives should have passed to remain a quarter of the sample.

<u>Step 2</u>: Calculate it's age

t/(t/1/2) = 2

⇒ with t = the age (or time) of the sample

⇒ with t(1/2) = the half-life time of the sample = 5470 years

⇒ with 2 = the number of halvf- lives passed

t/5470 = 2

t = 2*5470 = 10940 years

When there remains one-quarter of the sample, the age of the sample is 10940 years

You might be interested in
Investigations were carried out in a science lab to explore the topic of chemical and physical changes. Investigation A Step 1.
ozzi

Answer:

Investigation B, Step 2

Explanation:

The <em>colour change</em> is a good indication of a <em>chemical change</em>. The sugar molecules were most likely changing into something else.

Investigation A, Step 1. <em>Wron</em>g. The dissolving of salt is a <em>physica</em>l process.

Investigation A, Step 2. <em>Wrong</em>. You simply boiled off the water (a <em>physical</em> process) and recovered the salt.

Investigation B, Step 1. <em>Wrong</em>. The dissolving of sugar is a <em>physical</em> process.

4 0
3 years ago
Read 2 more answers
What kind of intermolecular forces act between two ammonia molecules
iragen [17]

Answer:

extensive hydrogen bonding

Explanation:

The high boiling points of water, hydrogen fluoride (HF) and ammonia (NH3) is an effect of the extensive hydrogen bonding between the molecules. The London dispersion force is caused by random and temporary changes in the polarity of atoms, caused by the location of the electrons in the atoms' orbitals.

Hope this helps :)

6 0
2 years ago
If the same amount of heat is added to 25.0 g of each of the metals, which are all at the same initial temperature, which metal
AVprozaik [17]

Answer:

The bismuth sample.

Explanation:

The specific heat c of a substance (might not be a metal) is the amount of heat required for heating a unit mass of this substance by unit temperature (e.g., \rm 1\; ^{\circ}C.) The formula for specific heat is:

\displaystyle c = \frac{Q}{m \cdot \Delta T},

where

  • Q is the amount of heat supplied.
  • m is the mass of the sample.
  • \Delta T is the increase in temperature.

In this question, the value of Q (amount of heat supplied to the metal) and m (mass of the metal sample) are the same for all four metals. To find \Delta T (change in temperature,) rearrange the equation:

\displaystyle c \cdot \Delta T = \frac{Q}{m},

\displaystyle \Delta T = \frac{Q}{c \cdot m}.

In other words, the change in temperature of the sample, \Delta T can be expressed as a fraction. Additionally, the specific heat of sample, c, is in the denominator of that fraction. Hence, the value of the fraction would be the largest for sample with the smallest specific heat.

Make sure that all the specific heat values are in the same unit. Find the one with the smallest specific heat: bismuth (\rm 0.123 \; J \cdot g\cdot \,^{\circ}C^{-1}.) That sample would have the greatest increase in temperature. Since all six samples started at the same temperature, the bismuth sample would also have the highest final temperature.

3 0
2 years ago
A sample of gas occupies a volume of 4.5 L at 20 Celsius. What volume will it occupy at -15 celsius, if the pressure remains con
nataly862011 [7]

Answer: 3.96L

Explanation:

PV = nRT

The way I like to do it, it's I get rid of whatever I do not need.

We have to do an equation for sure to make both sides equal and find our desired result.

The pressure is constant, so it would be constant in both sides, therefore, there is no point in using it.

The R is a constant used in both sides so there is no point on using it either.

We don't need to work with moles in this case, so let's forget about the moles.

Therefore we are left with only V (volume ) and T(Temperature)

Which would logically make this:

V1/T1 = V2/T2

OR

T1/V1 = T2/V2

Both of these would work, we always use whatever makes our calculations easier without complicating our lives with the algebra.

That should remind you of Charles' Law

Transform degrees into kelvins

20 + 273.15 = 293.15K

-15 + 273.15 = 258.15K

So, 4.5L/293.15K = V2/258.15K

V2 = (4.5L/293.15K) x 258.15K

V2 = 3.96L

8 0
2 years ago
What is Boyle's law​
Vadim26 [7]
Search it up a lot of information should appear. Try that
3 0
3 years ago
Read 2 more answers
Other questions:
  • What is the percent CdSO4 by mass in a 1.00 m aqueous CdSO4 solution?
    5·1 answer
  • What is the correct noble gas configuration for sr?
    11·1 answer
  • What is the difference between relative humidity and humidity?
    10·1 answer
  • What is described by the VSEPR theory?
    13·1 answer
  • Which of the following will have the highest boiling point?
    9·1 answer
  • 8 3/5- 3 4/5 what is the answer to this question ​
    6·1 answer
  • Which of the following is a chemical property of aluminum?
    8·1 answer
  • Some items, such as rubber, float on the water, while some items, such as gold, sink in
    7·1 answer
  • How can teh human body looose heat? (conduction, convecion, radiation) and WHY
    6·1 answer
  • How do electromagnetic waves transfer energy without a medium?.
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!