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
sweet [91]
3 years ago
12

Carbon -11 is a radioactive isotope of carbon. It’s half life is 20 minutes. What amount of the initial mass of 70.0g of C -11 a

toms in a sample will be left after 80 minutes
Chemistry
1 answer:
dusya [7]3 years ago
6 0

Answer:

4.38g

Explanation:

70.0/2 = 35g - 20 mins

35/2 = 17.5g - 40 mins

17.5/2 = 8.75g - 60 mins

8.75/2 = 4.375g - 80 mins

You might be interested in
Ice floats on water. For most other substances, however, the solid sinks in the liquid. Classify each of these statements based
sattari [20]

Answer:

1.High pressure will cause the liquid to become solid :

<u>Describe both water and other substances</u>

2.High pressure will cause the solid to become liquid <u>:</u>

<u>It describe none : neither water nor other substances </u>

<u>This statement is :False for both water and other substances</u>

3.The solid is more dense than the liquid :

It describe other substance

<u>This statement is :False for water but true for other substances.</u>

4. In a phase diagram, the solid-liquid coexistence line has a negative slope.

It describes water:

<u>This statement is :True for water because solid ice is less dense than liquid water.</u>

<u>False for other substance, they have positive slope</u>

5.The molecules are closest in the liquid phase.

<u>This statement is :False for water and other substances </u>

6.The solid is less dense than the liquid:

It Describes water because ice is less dense than liquid water

7. In a phase diagram, the solid-liquid coexistence line has a positive slope.

It describe other substances

<u>This statement is :True for other substances  but false for water</u>

8. The molecules are closest in the solid phase :

<u>Describes both water and other substances </u>

Explanation:

<u>Answers to statement 1 , 2,5 and 8</u>

<u>Answers to statement 1 , 2</u>

On increasing pressure and decreasing temperature , There occur<u> Phase transition</u> always for every substance :

From liquid to solid and gas to liquid

Hence,

In Both for water and other substance

<u>High pressure will cause the liquid to become solid.</u>

<u>Answers to statement 5,8 :</u>

2.The Particles of solid are closely packed hence there is maximum force of attraction between the particle of solid as compared to liquid and gases .

Hence , The molecules <u>of both water and other substance</u>s are closest in the solid phase

This also means that in liquid molecules are far apart .

Rest statement : 3, 4 ,6 ,7 are explained below(see attached image)

<u>The molecules are closest in the liquid phase is false statement  and does not describe both water and other substance</u>

<u>Ice floats on water. For most other substances, however, the solid sinks in the liquid.</u>

This can be explained using the phase diagram of <u>water </u>:

The line DB is  = the solid-liquid coexistence line

It has negative slope because , solid ice is less dense than liquid water . That is why ice floats on water because its density is less than water

Hence <u>Water is described truly by statement 4,6, </u>which are :

4. the solid-liquid coexistence line has a negative slope.

6.The solid is less dense than the liquid.

Rest 3,7 = describe by other substance

<u>other substance</u> : Solid  is more dense than the liquid ,the solid-liquid coexistence line has a positive slope

7 0
4 years ago
A 45 mL sample of nitrogen gas is cooled from 135ºC to 15C in a container that can contract or expand at constant pressure. Wha
Vanyuwa [196]

Answer:

V₂ =31.8 mL

Explanation:

Given data:

Initial  volume of gas = 45 mL

Initial temperature = 135°C (135+273 =408 K)

Final temperature = 15°C (15+273 =288 K)

Final volume of gas = ?

Solution:

The given problem will be solve through the Charles Law.

According to this law, The volume of given amount of a gas is directly proportional to its temperature at constant number of moles and pressure.

Mathematical expression:

V₁/T₁ = V₂/T₂

V₁ = Initial volume

T₁ = Initial temperature

V₂ = Final volume  

T₂ = Final temperature

Now we will put the values in formula.

V₁/T₁ = V₂/T₂

V₂ = V₁T₂/T₁  

V₂ = 45 mL × 288 K / 408 k

V₂ = 12960 mL.K / 408 K

V₂ =31.8 mL

8 0
3 years ago
How many moles of methane (CH4) is<br> 6.70 x 1022 atoms of methane?
suter [353]

Answer:

0.1113  mol

Explanation:

Data Given:

no. of atoms of CH₄= 6.70 x 10²² atoms

no. of moles of methane (CH₄) = ?

Solution:

we will find no. of moles of methane (CH₄)

Formula used

          no. of moles = no. of atoms / Avogadro's number

Where

Avogadro's number = 6.022 x 10²³

Put values in above equation

         no. of moles = 6.70 x 10²² atoms / 6.022 x 10²³ (atoms/mol)

         no. of moles = 0.1113  mol

So,

There are 0.1113 moles of methane.

8 0
3 years ago
Why does the flame go out on the Bunsen burner when the gas is turned off? (use the collision theory in your answer)
Gre4nikov [31]

Answer:

Explanation:

Well the gas is the fuel for the flame of course. The collision theory comes into play when the gas turns on, chemicals collide with one another. Then  reactions occur causing the flame. Then when you take away the fuel, the flame stops because there is no atoms or molecules to come together/collide with one another.

Sorry if its wrong or doesn't make sense... Wish you the best of luck on whatever your doing!

8 0
3 years ago
Describe the process of making the four major macromolecules.
dybincka [34]

Answer:

<em>Proteins, carbohydrates, nucleic acids, and lipids are the four major classes of biological macromolecules—large molecules necessary for life that are built from smaller organic molecules. Macromolecules are made up of single units known as monomers that are joined by covalent bonds to form larger polymers.</em>

Explanation:

Have a great day!

8 0
3 years ago
Read 2 more answers
Other questions:
  • In virginia and some other parts of the world, water has carved vast caverns out of underground limestone deposits. water, howev
    6·1 answer
  • How is temperature related to the physical change of a substance?<br><br>​
    11·2 answers
  • I really need help please
    12·1 answer
  • What do carbon, hydrogen, and oxygen atoms have in common?
    5·1 answer
  • NEED HELP QUICK!!!!!!!!!!!!!!
    15·2 answers
  • 10 g of nh4cl is added to 12.7 g of water. calculate the molality of the solution.
    11·1 answer
  • 88. Molybdenum, Mo is an element used in missile and aircraft parts. How many unpaired electrons are in Mo? 02 x 3 = .6 mol Catt
    12·1 answer
  • What is the total number of neutrons in the nucleus of a neutral atom that has 19 electrons and a mass of 39?
    8·1 answer
  • Can someone explain to me what numbers are acidic, base, or neutral on a ph scale?
    10·1 answer
  • Rocks are classified as igneous, sedimentary, or metamorphic based primarily on
    6·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!