A radioactive sample is placed in a closed container. Two days later only one-quarter of the sample is still radioactive. What is the half-life of this sample?

Answers

Answer 1

Answer:

2

Explanation:

The sample has halved twice.

1/2 of 1/2 is 1/4, and 1/2 of 1 is 1/2.


Related Questions

6. The overall process of photosynthesis has the balanced chemical equation 6CO2 +
6H2O → C6H12O6 + 602. What does this tell you about the relative amounts of carbon
dioxide and water consumed in this process?
ОООО
A. For every mole of carbon dioxide consumed, one mole of water is consumed.
B. For every six moles of carbon dioxide consumed, one mole of water is consumed.
C. For every six grams of carbon dioxide consumed, one gram of water is consumed.
D. For every gram of carbon dioxide consumed, one gram of water is consumed.

Answers

Answer:

The right answer is option A

Please help thank you

Answers

Answer:

be pulled into the new star

Explanation:

Because it is heavier, with more mass and more gravitational force than our little Sun.

Identify two ways to measure mass​

Answers

Answer:

Putting it in water, and see the displacement of the water, or just measuring its weight and devide it by the gravitational pull

Scientists use a balance to obtain an object’s mass. A balance compares an object with a known mass to the object in question. One example of a balance is the triple beam balance. The standard unit of measure for mass is based on the metric system and is typically denoted as kilograms or grams.

1. Liver Balance
2. Physical balance
3. Electronic Balance

Describe the differences between models and scientific laws and theories. (

Answers

Answer:

Scientific laws and theories have different jobs to do. A scientific law predicts the results of certain initial conditions. ... In simplest terms, a law predicts what happens while a theory proposes why. A theory will never grow up into a law, though the development of one often triggers progress on

Explanation:

Which of the following alcohols will give a positive chromic acid test?
(A) tert-butanol (B) cyclohexanol (C) pentan-3-ol
(D) both A and B (E) both B and C

Answers

the answer is both B and C

positive chromic acid test is indicated by disappearance of orange colour from chromic ions and appearance of blue-green color from Chromium (iii) ion (reduction of chromium ion from CrO4 - to Cr3+)

positive chromic test indicated functional groups that can be oxidized.

cyclohexanol can be oxidized to become cyclohexanone

and pentan-3-ol can be oxidized to become pentan-3-one

hence both B and C will show positive chromic acid test

A) tert butanol although contains alcohol functional group, cannot be further oxidized as it is a tertiary alcohol

(E) Both B and C

What is chromic acid test?

The chromic acid test uses the Jones reactant to oxidize aldehydes and alcohols and reduce the chromic acid, resulting in a color change.Positive chromic acid test is indicated by disappearance of orange color from chromic ions and appearance of blue-green color from Chromium (III) ion (reduction of chromium ion from [tex]CrO_4^- \text{to } Cr^{3+}[/tex])

Positive chromic test indicated functional groups that can be oxidized.

⇒Cyclohexanol can be oxidized to become cyclohexanone.

⇒Pentan-3-ol can be oxidized to become pentan-3-one.

Hence, both B and C will show positive chromic acid test.

A) tert-butanol although contains alcohol functional group, cannot be further oxidized as it is a tertiary alcohol.

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Is Calcium, Ca a metal or a non-metal? Explain your thinking.

Answers

Calcium is a metal. It is an alkaline earth metal. Calcium is a metal because it is in group 2 which makes it an alkaline earth metal and a powerful reducing agent that loves to react with nonmetals especially powerful oxidizing agents like fluorine and chlorine.

Answer:

Calcium is a metal, particularly,an alkali earth metal

Explanation:

It donates two electrons to form cation

Ca+2e––>Ca^2+

how can you use terms such as thermal energy, particles, motion, and flow to explain the movement of heat in our world

Answers

Answer:  Thermal energy is the kinetic energy of particles and heat is the term used to describe how this energy may flow to other systems, such as in a radiator.

Explanation:  Molecules have a level of kinetic energy that can be measured by temperature.  Higher temperatures result in more rapid and frequent collisons of particles in motion.  Heat is the term used to measure the quantity of vibration energy in a given system.  The SI unit for heat energy is the Joule.  The water molecules in a pot of boiling water have a kinetic energy sufficient for them to break away from other water molecules and become gaseous (boiling point).  The heat energy in 1 liter of water at 95C can be calculated in terms of Joules/liter, based on the specific heat of water (e.g., in units of J/gC).  This heat can flow to other systems.  A home boiler heater unit heats water tha can be pumped around the house ehre it will flow from radiators into thje surrounding air.

Heat is the word used to explain how this energy may transfer to other systems, such as in a radiator, and thermal energy is the kinetic energy of particles.

What is thermal energy?

By virtue of its temperature, a system in a condition of thermodynamic equilibrium has thermal energy or internal energy. Unlike the energy of systems that are not in a state of thermodynamic equilibrium, thermal energy cannot be transformed into meaningful work as quickly.

For instance, the same fluid or solid in a thermodynamic equilibrium state with the same energy (as thermal energy) cannot do work unless it is combined with another substance at a different temperature, as in a heat engine. However, the same fluid or solid in a moving state with the same energy (as mechanical energy) can be converted to work in some mechanical device, such as a windmill or a waterwheel.

Therefore, heat is the word used to explain how this energy may transfer to other systems, such as in a radiator, and thermal energy is the kinetic energy of particles.

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An object measures 6.2 cm×13.7 cm×26.9 cm. Which value is the length of the object?

Answers

Answer: 6.2cm

Explanation: because don’t forget it’s

Length • Width • Height


In your own words, summarize the contrasting arguments of Democritus and Aristotle about the composition (make up) of matter.

Answers

Answer:

Aristotle disagreed with Democritus and offered his own idea of the composition of matter. According to Aristotle, everything was composed of four elements: earth, air, fire, and water. The theory of Democritus explained things better, but Aristotle was more influential, so his ideas prevailed.

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The ionic radius of a sodium ion is 2.27 angstroms (A) . What is this length in um

Answers

[tex]\boxed{\sf 1Å=10^{-10}m}[/tex]

[tex]\\ \rm\longmapsto 2.27Å[/tex]

[tex]\\ \rm\longmapsto 2.27\times 10^{-10}m[/tex]

[tex]\\ \rm\longmapsto 0.227\times 10^{-9}m[/tex]

[tex]\\ \rm\longmapsto 0.0227\times 10^{-8}m[/tex]

[tex]\\ \rm\longmapsto 0.00227\times 10^{-7}m[/tex]

[tex]\\ \rm\longmapsto 0.00023\times 10^{-6}m[/tex]

[tex]\\ \rm\longmapsto 0.00023\mu m[/tex]

Therefore, length = 2.27 × [tex]10^{-4}[/tex] um

Ionic radius of sodium = 2.27 angstrons

1 angstron = [tex]10^{-10} m[/tex]

1 m =[tex] 10^6[/tex] micrometer (um)

So, 1 angstron = [tex]10^{-10} m\times10^6 um/m = 10^{-4} um[/tex]

Hence,

2.27 anstrons × [tex]10^{-4}[/tex] um/angstron =

2.27 ×[tex] 10^{-4} [/tex]um

So, length = 2.27 × [tex]10^{-4}[/tex] um

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Which of the following compounds has the lowest percent gold content by mass which one has the highest percent gold content by weight?

a. AuOH
b. Au(OH)3
c. AuCI3
d. AuI3

Answers

highest percentage of gold by weight can be determined by looking at the atomic mass of the other elements in the compound. the smaller the total of mass of the other elements, the heigher the percentage of Au will be in that compound

a. AuOH, OH- = 17 gram/mole
b. Au(OH)3, 3 x OH- = 3 x 17 = 51 gram/mole
c. AuCl3 = 3x35.5= 106.5 gram/mole
d. AuI3 = 3x127 = 381 gram/mole


as we can see AuOH has the least Molecular mass, hence % of Au will be the highest compared to other choices

Answer: A

Answer:D. AuI3

Explanation:

Help!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!​

Answers

Answer:

bubble and foam!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

d. bubble and foam
akshaishsushsusisneysisj

Which method is used to separate the following mixture (a) water + kerosene​

Answers

Answer:

The separation of kerosene, oil, and water are immiscible liquids, so they can be separated funnel.

How does specific heat capacity affect heating rate

Answers

Answer:

The specific heat capacity affect heating rate by the amount of heat needed to raise the temperature of 1 gram of a substance 1 degree Celsius (°C).

Explanation:

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Filtration is the most appropriate method for separating a solution of water and which substance?

A. alcohol

B. salt

C. sand

D. sugar

Answers

Answer:

Sand

Explanation:

If you get salt or sugar in your water, you have to legit desalinate it to get the water and item out. You need to evaporate the water by increasing temperature and then lower temperature to separate the substances.

If you have alcohol, you need to distill it by trapping it and stuff.

With sand, the molecules are much larger which lets you separate the substances easily.

For example, on a beach, you can slap a handful of sand in your pail, but the sand sinks to the bottom right? You can just pour out the water.

The chemical reaction represented as “AB ⇒ A + B” is a ______

Answers

decomposition reaction

Answer:

Below

Explanation:

This would be a decomposition reaction. This occurs when a compound breaks down into 2 + simpler substances. We can see this from AB --> A + B, one compound (AB) breaks down into 2 simple substances ( A and B ).

Hope that helped!

The percent by mass of nitrogen for a compound is found to be 46.7% Which of the following could be this species?

Answers

The percent by mass of an element in a compound is obtained as the ratio of the mass of the atom to the relative molecular mass of the compound multiplied by 100.

If we look at the representations shown in the image, we will notice that the red ball symbolizes the oxygen atom while the blue ball symbolizes the nitrogen atom.

The percent by mass of nitrogen in NO is 46.7%. This is obtained as follows;

Molar mass = 14 + 16 = 30

percent by mass of nitrogen = 14/30 * 100 = 46.7%

NO is the diagram that has only one red and blue ball respectively.

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Which of these outcomes is conclusive evidence that mixing sugar in water is a physical change?

Answers

Answer:

» Water changes from colorless to a pale colored solution.

» The solubility of water reduces because a saturated solution is formed.

» The freezing point of water decreases. [colligative property]

» The boiling point of water elevates [colligative property]

» The vapour pressure of water lowers [colligative property]

Explanation:

[tex].[/tex]

Loss of atmospheric ozone has led to an ozone "hole" over Antarctica. The process occurs in part by three consecutive reactions. (Each of the reactants and products in these reactions are gases.)
(1) Chlorine atoms react with ozone (O3) to form chlorine monoxide and molecular oxygen.
(2) Chlorine monoxide forms ClOOCl.
(3) ClOOCl absorbs sunlight and breaks into chlorine atoms and molecular oxygen. If the coefficient for a particular substance is "1", do not write the "1" in the balanced equation. For example, instead of writing "1Cl(g)", simply write "Cl(g)".
(a) Write a balanced equation for each step, including the state of each molecule.
(b) Write an overall balanced equation for the sequence.

Answers

Ozone O₃ consists of a strong reactive gas made up of three atoms of oxygen. Ozone occurs on the Earth as natural and man-made gas.

Ozone impacts life on Earth in positive or harmful ways depending upon its location in the atmosphere.

From the information given, we are to balance the reactant and the product that leads to the formation of Ozone by following each step.

Step 1:

2Cl° + 2O₃           2ClO°        +        2O₂

                          Chlorine               molecular

                          monooxide            oxygen

Step 2:

2ClO°                  ClOOCl

Step 3:

ClOOCl     + sunlight   →    2Cl°      + O₂

(b)

The Overall balanced equation can be expressed as:

2O₃    →    3O₂

Therefore, from the above explanation we can see the step by step process for the balanced equation and the overall balanced equation.

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Which of the following statements is incorrect for the reaction of 1,3- butadiene with a substituted alkene CH2=CHX when X is a nitro group?

Answers

Answer:

hugsvsbsbbsnjsjsnsbsbbzbd

What is cylopasm?

A. The center of control for a cell.

B. The organelle that create protein for a cell.

C. The membrane that surrounds a cell.

D. The substance that holds the organelle of a cell in place.

Answers

Answer:D-The substance that hold the organelle of a cell in place.

Hope that helps!

Answer:

D. The substance that holds the organelle of a cell in place.

Explanation:

Cytoplasm is the material filled within the cell, and it holds the organelles in a cell in place.

Find the final pressure of a gas at 150. K, if the pressure of the gas is 210. kPa at 120. K.

Answers

Answer:

final pressure = 262.5kpa

Explanation:

using Gay-Lussac's Equation

P1/T1 = P2/T2

P1 = 210kpa = 210000pa

T1 = 120k

P2 = ?

T2 = 150k

210000/120 = P2/150

1750 = P2/150

P2 = 1750 X 150

P2 = 262500pa

P2 = 262.5kpa

How does convection affect the earths atmosphere

Answers

Answer:

I think the layers of the atmosphere does temperature increase with increasing height. It is affected by convection because it heats the lower atmosphere. It is affected by conduction because the is the transfer of thermal energy. I guess

Hope this help!

The volume of real gas will change if “P” increases upto 500 atm and temperature decrease upto 0°C A. Volume increases by 0.05% B. Volume decreases by 0.05% C. Volume increases 20% D. Vol decreases 20%​

Answers

B.volume decreases by 0.05%

We have that The volume of real gas will change if “P” increases upto 500 atm and temperature decrease upto 0°C there will be

. Volume decreases by 0.05%

OPtion B

From the question we are told that

if “P” increases upto 500 atm

temperature decrease upto 0°C

Generally the equation for the ideal gas equation  is mathematically given as

P=\frac{nRT}{V}

Where

n=1

R=0.08

Therefore

The volume is directly proportional to temperature

Therefore

. Volume decreases by 0.05%

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A biochemist carefully measures the molarity of glucose in of cell growth medium to be . Unfortunately, a careless graduate student forgets to cover the container of growth medium and a substantial amount of the solvent evaporates. The volume of the cell growth medium falls to . Calculate the new molarity of glucose in the cell growth medium. Round each of your answers to significant digits.

Answers

This is the answer !!!!!!

which square is more dense

Answers

Answer:

mass ,volume and density

Which of the following is a true statement?

Periods form horizontal rows, groups form vertical columns Periods form horizontal rows, groups form vertical columns Gases form horizontal rows, categories form vertical columns Gases form horizontal rows, categories form vertical columns Groups form horizontal rows, periods form vertical columns Groups form horizontal rows, periods form vertical columns categories form horizontal rows, gases from vertical columns

Answers

Answer:

The correct answer is A.

The horizontal rows on the periodic table are called periods, while the vertical columns are called groups.

hope this hepl's

Outline the steps involved in the synthesis of 4-bromo-3-nitro-phenol from 4-bromobenzoic acid.

Answers

Answer:

[tex]4 - bromobenzoic \: acid \\ ↓ \\ { \tt{ \{soda \: lime \: and \: calcium \: oxide}} \\ { \tt{and \: heat \}}} \\ ↓ \\ 4 - bromobenzene \\ ↓ \\ { \tt{ \{chlorine \: and \: aluminium \: chloride \}}} \\ ↓ \\ 4 - bromo - 2 - chlorobenzene \\ ↓ \\ { \tt{ \{water \: and \: sodium \: hydroxide \}}} \\ ↓ \\ 4 - bromophenol \\ ↓ \\ { \tt{ \{conc.nitric \: acid \: at \: 60 \degree c}} \\ { \tt{and \: sulphuric \: acid \}}} \\ ↓ \\ 4 - bromo - 3 - nitrophenol[/tex]

In brackets, are the reagents

a) Briefly discuss hydrolysis of sicl4​

Answers

Answer:

Types of Hydrolysis

There are several types of hydrolysis, and we will look at them in brief below.

Salts: This is the most common type of hydrolysis. Hydrolysis of salts generally refers to the reaction of salt with water where it involves the interaction between cations or anions of salts and water. During hydrolysis, a salt breaks down to form ions, completely or partially depending upon the solubility factor.

Acid and Base: Acid–base-catalysed hydrolysis can be found during the hydrolysis of esters or amides. Here, the process of hydrolysis occurs when water or hydroxyl ion reacts with the carbon of the carbonyl group of the ester or amide where new compounds are formed. The products of both hydrolysis are compounds with carboxylic acid groups.

ATP: Most biochemical reactions that occur in living organisms are in the form of ATP hydrolysis which takes place with the help of enzymes acting as catalysts. The catalytic action of enzymes allows the hydrolysis or breaking down of proteins, lipids, oils, fats and carbohydrates.

Explanation:

HURRY PLEASE!! A student builds a model of a town. The model's scale in 1:48. Fill in the missing
information in the table.
Distance between
in real life
in model
School and library
18.0 m
0375m 0
Grocery store and city hall
Select
14
26 m
Post office and park
9.6 m
30 m
MIT
864 m

Answers

123 store stop
School and store
48
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