A radioisotope has a half-life of 5 minutes. What fraction of material would remain after
half an hour?

Answers

Answer 1
It should be 1/32 after half an hour.

Related Questions

18.2L of gas at 95°C and 760 torr is placed in a 15L container at 80 degrees * C ; what is the new pressure ?

Answers

Answer:

884.56 torr

Explanation:

Formula: [tex]\frac{P_{1}V_{1} }{T_{1}} = \frac{P_{2}V_{2} }{T_{2}}[/tex]

P = Pressure

V = Volume

T = Temperature in kelvin (Celsius + 273.15)

[tex]\frac{(760)(18.2) }{368.15} = \frac{P(15) }{353.15}[/tex]

[tex]P = \frac{(760)(18.2)(353.15) }{(368.15)(15)}[/tex]

P = 884.56169

On a hot day, a 15.0 kg window increased from 20.0 degrees C to 26.7 degrees C. How much heat energy did the glass window absorb? (specific heat of glass = 0.840 J/gC)

Answers

Answer: The heat energy absorbed by the glass window is 84420 J.

Explanation:

Given: Mass = 15.0 kg (1 kg = 1000 g) = 15000 g

Specific heat capacity = [tex]0.840^{o}C[/tex]

Initial temperature = [tex]20^{o}C[/tex]

Final temperature = [tex]26.7^{o}C[/tex]

Formula used to calculate heat energy is as follows.

[tex]q = m \times C \times (T_{2} - T_{1})[/tex]

where,

q = heat energy

m =  mass of substance

C = specific heat capacity

[tex]T_{1}[/tex] = initial temperature

[tex]T_{2}[/tex] = final temperature

Substitute the values into above formula as follows.

[tex]q = m \times C \times (T_{2} - T_{1})\\= 15000 g \times 0.840J/g^{o}C \times (26.7 - 20.0)^{o}C\\= 84420 J[/tex]

Thus, we can conclude that heat energy absorbed by the glass window is 84420J.

HELP ASAP 10 POINTSSS


In this diagram, the medium on top is air and the medium on bottom is glass. Which vocab word best describes what is happening when the light wave passes from the air into the glass?
Question 2 options:


resolution


diffraction


refraction


reflection

Answers

Answer: refraction

Explanation: this is because during refraction light moves from one medium to another.

Which type of changes are melting, freezing, and boiling?​

Answers

Answer:

the changes are physical changes

A sample of helium has a volume of 3.49 L at 741 mmHg. What would be the volume if the pressure
were changed to 760 mmHg at the same temperature?

show work

Answers

P1: 741 mmHg

V1: 3.49 L P1 x V1 / P2= (741 mmHg) (3.49 L) / 760 mmHg = 3.40 L

P2: 760 mmHg

V2: ? L



A gas has a temperature of 14 °C, and a volume of 4.5 liters. If the temperature is raised to 29
°C and the pressure is not changed, what is the new volume of the gas

Answers

The new volume of the gas wii be 4.7 liters.

Which of these phrases accurately describe disproportionation? Check all that apply.


A single compound reacts with itself.


A single compound oxidizes and reduces a second compound.


A single compound is simultaneously oxidized and reduced.


A single compound is produced by the reaction of two ions.


A single compound acts as both the oxidizing agent and the reducing agent.


ANSWER: A,C,E on E2020

Answers

Answer:

A single compound is simultaneously oxidized and reduced.

Explanation:

In chemistry, disproportionation is a simultaneous oxidation and reduction of a single chemical specie.

What this means is that; in a disproportionation reaction, only one compound is both oxidized and reduced. This implies that two products are formed during disproportionation. One is the oxidized product while the other is the reduced product.

Consider the disproportionation of CuCl shown below;

2CuCl -----> CuCl2 + Cu

Here, CuCl2 is the oxidized product while Cu is the reduced product.

Answer:

A & c & e

Explanation:

Find the number of grams in 16.95 mol hydrogen peroxide (H2O2). Round your
answer to two decimal places and be sure to include the proper units.

Answers

Answer: There are 576.46 number of grams present in 16.95 mol hydrogen peroxide [tex](H_{2}O_{2})[/tex].

Explanation:

Number of moles is defined as the mass of substance divided by its molar mass.

The molar mass of [tex]H_{2}O_{2}[/tex] is 34.01 g/mol. Hence, mass of hydrogen peroxide present in 16.95 moles is calculated as follows.

[tex]Moles = \frac{mass}{molarmass}\\16.95 mol = \frac{mass}{34.01 g/mol}\\mass = 576.46 g[/tex]

Thus, we can conclude that there are 576.46 number of grams present in 16.95 mol hydrogen peroxide [tex](H_{2}O_{2})[/tex].

How many moles are there in 8.25 x 10^26 molecules of methane (CH4)?

Answers

Answer:

i dont know

Explanation:

because i dont know 45

Helppppppppp pweaseeeee

Answers

Answer:

Explanation:

b

On a hot day, a 15.0 kg window increased from 20.0 degrees C to 26.7 degrees C. How much heat energy did the glass window absorb? (specific heat of glass = 0.840 J/gC)

Answers

Answer: The heat energy absorbed by glass window is 84420 J.

Explanation:

Given: Mass = 15 kg (1 kg = 1000 g) = 15000 g

Initial temperature = [tex]20^{o}C[/tex]

Final temperature = [tex]26.7^{o}C[/tex]

Specific heat capacity = [tex]0.840 J/g^{o}C[/tex]

Formula used is as follows.

[tex]q = m \times C \times (T_{2} - T_{1})[/tex]

where,

q = heat energy

m = mass of substance

C = specific heat capacity

[tex]T_{1}[/tex] = initial temperature

[tex]T_{2}[/tex] = final temperature

Substitute the values into above formula as follows.

[tex]q = m \times C \times (T_{2} - T_{1})\\ q = 15000 g \times 0.840 J/g^{o}C \times (26.7 - 20)^{o}C\\q = 84420 J[/tex]

Thus, we can conclude that the heat energy absorbed by glass window is 84420 J.

Add coefficients to balance the equation to make water.
H2(g) +O2 (g)H20 (1)

Answers

Answer:

2H2+2O2=2H2O

Explanation:

hope this helps

Consider the following reaction:

2CuCl2 + 4KI → 2CuI + 4KCl + I2

When 0.64 grams of CuCl2 reacts with 0.78 grams of KI, how many grams of I2 are formed?











What is the limiting reactant?


What is the excess reactant?
PLEASE I NEED HELP

Answers

Your limiting is CuCI2 and the excess is KI (from what i’ve heard from my tc to find it just use the moles or look at the grams)Do you want me to do the qn and give u the ans or?

Explanation:You have more grams of KI than CuCI2
irl example : I need 200g of flour to bake 1 muffin and 100g of butter.But I have 300g of butter and only 200g of flour.This means I can only bake up to 1 muffin since I got excess grams of butter.But to use up all my 300g of butter I need 400g more of flour.Making my butter the excess while my flour the limiting since I have less of it and it also determines how much muffin would I get at the end of the bake.

im sorry if that example sounds clowny T-T

At a high concentration do you have more or less particles per unit volume

Answers

Answer:

More particles per unit volume

Explanation:

Concentration means the amount of solute in a solution. Now, the amount of solute also means the number of particles of solute present in a solution.

Hence, when we use the term "high concentration", we imply that the amount of solute present or the number of particles present in a solution is high.

Thus, at high concentration, there are more solute particles than solvent particles in a solution.

4. At what temperature will 5.00 g of Cl, exert a pressure of 900. torr at a volume of 750 ml?​

Answers

Answer:

p=27.8atm

Explanation:

P = 27.8atm

At what temperature will 5.00 g of Cl2 exert a pressure of 900. mmHg at a volume of 750.

If the half-life of a radioactive substance is 500 million years and you have 48 atoms of it, how many half-lives will have passed by the time that 6 atoms of the substance remain?
O A. 3
O B. 2
O C. 4
O D. 5

Answers

Answer: 3

Explanation:

Hydrogen gas can be produced in the laboratory by the reaction of magnesium metal with hydrochloric acid, according to the following equation:
Mg(s) + 2HCl(aq) --> MgCl2(aq) + H2(g)

a. How many grams of hydrogen can be produced when 4.00 g of HCl is added to 3.00 g of Mg?

b. Assuming STP, what is the volume of this hydrogen?

Answers

Answer: 0.11 g H2

Explanation: just took test and got it right

What is the pressure of the gas if we have 3.50 moles of helium at -50.0°C
in a rigid container whose volume is 25.0 liters?
003 kPa
-58.2 kPa
259.6 kPa
0.0 kPa

Answers

Answer:

259.6kPa

Explanation:

because it is big

Magnesium (used in the manufacture of light alloys) reacts with iron(III) chloride to form magnesium chloride and iron. A mixture of 41.0 g of magnesium and 175.0 g of iron(III) chloride is allowed to react. Identify the limiting reactant and determine the mass of the excess reactant present in the vessel when the reaction is complete. Select one: a. Limiting reactant is Mg; 7.4 g of FeCl3 remain. b. Limiting reactant is Mg; 46.5 g of FeCl3 remain. c. Limiting reactant is FeCl3; 1.7 g of Mg remain. d. Limiting reactant is FeCl3; 37.8 g of Mg remain. e. Limiting reactant is Mg; 134.0 g of FeCl3 remain.

Answers

Answer:

Limiting reactant is FeCl3; 1.7 g of Mg remain.

Explanation:

From the question;

The equation is;

3Mg(s) + 2FeCl₃(s) → 3MgCl₂(s) + 2Fe(s)

Amount of Mg = 41 g/24.31 g/mol = 1.687 moles

The limiting reactant yields the least amount of MgCl2

3 moles of Mg yields 3 moles of MgCl2

Hence 1.687 moles of Mg yields yields 1.687 moles of MgCl2

FeCl₃ = 175 g/162.2 g/mol = 1.0789 moles

2 moles of FeCl3 yields 3 moles of MgCl2

1.0789  moles of FeCl3 yields 1.0789  * 3/2 = 1.61835 moles of MgCl2

Hence FeCl3 is the limiting reactant

3 moles of Mg reacts with 2 moles of FeCl3

x moles of Mg reacts with 1.0789  of FeCl3

x = 3 * 1.0789  /2 = 1.61835 moles of Mg

Mass of Mg reacted = 1.61835 moles * 24.31 = 39.342 g

Mass of excess Mg = 41 g - 39.342 g = 1.7 g

 

                   

                   

 

                           

                         

       

When a solute is added to water, the boiling point

Answers

Answer:

Boiling-point elevation describes the phenomenon that the boiling point of a liquid (a solvent) will be higher when another compound is added, meaning that a solution has a higher boiling point than a pure solvent. This happens whenever a non-volatile solute, such as a salt, is added to a pure solvent, such as water.

Which forward reaction shows an increase in entropy (disorder)?explain

A.H2(g) + CuO (s) --> H2O(l) + Cu(s)
B.HCl(g) + NH3(g) --> NH4Cl(s)
C.CaCO3(s) -> CaO(s) + CO2g)
D.H2O(g) + O2(g) --> 2H2O)

Answers

Explanation:

Entropy also increases when solid reactants form liquid products. Entropy increases when a substance is broken up into multiple parts. The process of dissolving increases entropy because the solute particles become separated from one another when a solution is formed. Entropy increases as temperature increases. S = entropy

k_{b} = Boltzmann constant

\ln = natural logarithm

\Omega = number of microscopic configurations

I don't understand with the question number 4, does anybody understand how to do it?

Answers

Answer:

iodine = I

sodium= Na

oxygen= O2

aluminum = AI

nitrogen=N

sulfur= S

bromine =Br

magnesium =Mg

Why are shadows shorter around noon?
Make sure you give a full, detailed answer, not just one sentence.

Answers

Answer: Answer is in the Explanation.

Explanation: At noon the sun is directly above in the sky, the sun's rays are falling on the body making the shadow smaller. While in the evenings and mornings the sun is at a inclined position, so the sun's rays are falling at a inclined position making the body's shadow larger.  

I looked it up on the internet and reworded it as good as I could.

What can you say about the forces between the particles of these gases)​

Answers

Answer:

Gas – In a gas, particles are in continual straight-line motion. The kinetic energy of the molecule is greater than the attractive force between them, thus they are much farther apart and move freely of each other. In most cases, there are essentially no attractive forces between particles.

Explanation:hopes this helps:)

Bacteria live on skin of humans. The bacteria receive food and shelter form human beings. Most bacteria are harmless and pose little or no threat to humans. This is an example of

Answers

Answer: symbiotic relationship

Explanation:

Concerning the disposal of materials at the end of the experiment, which methods are safe? Check all that apply.


[ANSWERS]


B. Dispose of pH paper in the trash.


C. Dump the cabbage indicator solution down the drain.


D. Ask your teacher to neutralize the acids and bases before disposal.

Answers

Answer:

B. Dispose of pH paper in the trash.

C. Dump the cabbage indicator solution down the drain.

D. Ask your teacher to neutralize the acids and bases before disposal.

Explanation:

Safe disposal of waste means disposal of waste in such a way that it does not pose a threat to the environment.

When pH paper is properly disposed in the trash, it does not constitute any risk to the environment.

When a cabbage indicator solution is disposed down the drain it does not contaminate the environment. It moves directly into the sewers and is properly disposed.

When acids and bases are properly neutralized before disposal, they don't lead to acid or base contamination of the environment.

Which of the following represents alpha decay?

Answers

Answer: b

Explanation: alpha decay or particle consist of two protons and two neutrons hence it is a helium nucleus.

An alpha particle [tex]\binom {4} {2}[/tex]He is produced in alpha decay reactions, while the parent nucleus' atomic number and mass number drop by 2 and 4 correspondingly.

Alpha decay:

Alpha decay is a nuclear process whereby an unstable nuclear transforms into a different element by ejecting particles composed of two protons and two neutrons. The alpha particle also referred to as a helium nucleus, is the expelled unit of matter. Alpha particles have large masses and electrostatic attraction.An atomic number decreases by 2 and the atomic weight drops by 4 when a radioactive nucleus disintegrates by emitting [tex]\bold{\alpha}[/tex] particle.

Therefore, the final answer is "Option B".

Find out more about the alpha decay here:

brainly.com/question/14081292

What is the molarity of a solution made of 2.45 moles of LiCl in 4.75 L of solution?

Answers

Answer:

.52 M

Explanation:

moles ÷ liters = molarity

2.45 ÷ 4.75 = 0.5157894737

rounding it = .52

Can someone help me with these answers please I’ll give Brainly !!!!

Answers

1.What's the first thought that comes to mind when you hear "nuclear"? nuclear, that's the word. well the first thing that comes into everyone's mind in nuclear and they have to think it then think of words that associate with it.

2.the most important point of something.

3.test site

4.

What are the only types of metals that be magnetized?

Answers

Iron, nickel, cobalt? I’m not really sure. Hope this helped a little bit.
iron colbalt and nickel is the answer
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