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
masya89 [10]
3 years ago
5

A 200-gram sample of a radioactive nuclide is left to decay for 60 hours. At the end of 60 hours, only 25 grams of the sample is

left. What is the half-life of the nuclide sample?
60 hours
30 hours
40 hours
20 hours ---> I think 20??
Chemistry
1 answer:
Goryan [66]3 years ago
5 0
Half life is the time taken by a radioactive isotope to decay by half its original mass. 
The original mass is 200 g
Time taken is 60 hours
Final mass is 25 g
Therefore;
Final mass = Original mass × (1/2)^n; where n is the number of half lives.
25 = 200 (1/2)^n
1/8 = (1/2)^n
    n = 3 
Three half lives = 60 hours
1 half lives = 20 hours
Therefore; the half life of the radioactive nucleus is 20 hours
You might be interested in
4Fe + 3O2 → 2Fe2O3
Black_prince [1.1K]

n(2Fe2O3)=10g/319.374amu=0.03mol

n(4Fe+3O2)=0.03 mol

m(4Fe+2O2)=Mn=319.374×0.03=9.58=10

7 0
3 years ago
Read 2 more answers
Conservation of Mass means:
Anarel [89]

Answer:

Conservation of mass mean mass cannot be created nor destroyed

Explanation:

3 0
3 years ago
Read 2 more answers
It requires 334 kJ of heat to melt 1 kg of ice. The largest known iceberg had a volume of about 3.1 x 1013 m³. How much heat was
umka21 [38]

The  amount of heat required to melt the iceberg at 9.58 * 10¹⁸ kJ.

<h3>What is the amount of heat required to melt an iceberg that has a volume of about 3.1 x 1013 m³?</h3>

The heat required to melt a unit mass of ice is known as the latent heat of fusion.

The latent heat of fusion of ice of 1 kg= 334 kJ of heat

Mass of iceberg = 3.1 x 10¹³ m³ * 917 kg = 2.8427 * 10¹⁶ kg

Amount of heat required = 2.8427 * 10¹⁶ * 334 = 9.58 * 10¹⁸ kJ.

Therefore, the amount of heat required to melt the iceberg at 9.58 * 10¹⁸ kJ.

Learn more about latent heat of fusion at: brainly.com/question/87248

#SPJ1

8 0
2 years ago
How many moles of silane gas (SiH4) are present in 8.68 mL<br> measured at 18 0C and 1.50 atm?
makvit [3.9K]

Answer:

5.45*10⁻⁴ moles of silane gas (SiH₄) are present in 8.68 mL  measured at 18°C and 1.50 atm.

Explanation:

An ideal gas is a theoretical gas that is considered to be composed of point particles that move randomly and do not interact with each other. Gases in general are ideal when they are at high temperatures and low pressures.

An ideal gas is characterized by three state variables: absolute pressure (P), volume (V), and absolute temperature (T). The relationship between them constitutes the ideal gas law, an equation that relates the three variables if the amount of substance, number of moles n, remains constant and where R is the molar constant of the gases:

P * V = n * R * T

In this case:

  • P= 1.5 atm
  • V= 8.68 mL= 0.00868 L (being 1000 mL= 1 L)
  • n= ?
  • R= 0.082 \frac{atm*L}{mol*K}
  • T= 18 C= 291 K (being 0 C= 273 K)

Replacing:

1.5 atm* 0.00868 L= n* 0.082\frac{atm*L}{mol*K} *291 K

Solving:

n=\frac{1.5 atm*0.00868 L}{0.082 \frac{atm*L}{mol*K}*291 K}

n= 5.45*10⁻⁴ moles

<u><em>5.45*10⁻⁴ moles of silane gas (SiH₄) are present in 8.68 mL  measured at 18°C and 1.50 atm.</em></u>

8 0
2 years ago
The diagram below shows the positions of the Earth, Moon, and Sun. What is the date?
Anna35 [415]
Answer is: <span>B) June 21.
This is summer solstice or midsummer.
</span>Summer solstice occurs when a planet's geographical pole<span> on Northern H</span>emisphere is most inclined toward the Sun. <span>Earth's maximum </span>axial tilt<span> toward the </span>Sun is 23.44° and <span>the Sun reaches its </span>highest altitude<span> of the year on the summer </span><span>solstice.</span>
5 0
3 years ago
Read 2 more answers
Other questions:
  • what volume (L) of fluorine gas is required to react with 2.31 g of calcium bromide to form calcium fluoride and bromine gas at
    14·1 answer
  • The chemical formula for baking soda is NaHCO. Does baking soda contain metallic or non-metallic elements? Which one is which?
    5·1 answer
  • A stream of negatively charged particles is called:
    7·1 answer
  • Match the following terms with their definitions:
    11·2 answers
  • Calculate the bond energy per mole for breaking all the bonds in methane, CH4. Express your answer to four significant figures a
    12·2 answers
  • Answer the questions about the characteristics of the elements in group 1 (the alkali metals). What happens when the elements in
    7·1 answer
  • The North Pole of a magnet will attract to the South Pole of another magnet. True or False
    5·1 answer
  • Which is a semi conductor? metal, nonmetal, mettaliod
    8·2 answers
  • How many moles is 7.78 x 1024<br> formula units of MgCl2?
    13·1 answer
  • How many grams of Ca(OH)2 are needed to produce 500 mL of 2.99 M Ca(OH)2 solution? 1L=1000mL
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!