HELP ASAPPPP

Cobalt-60 has a half-life of 5.3 years. A sample measures 0.95g of cobalt-
60. If the sample originally had 5.2g of colbalt-60, determine its age in
years or the time elapsed in years. Round up answer in the nearest whole
number and no additional text or unit. *

Answers

Answer 1

Answer:

13 years

Explanation:

From;

0.693/t1/2 = 2.303/t log (No/N)

Where;

t1/12 = half-life of Cobalt-60 = 5.3 years

t = time taken = the unknown

No = mass of radioactive material originally present = 5.2 g

N = mass of radioactive material at time t = 0.95 g

Substituting values;

0.693/5.3 = 2.303/t log (5.2/0.95)

0.131 = 2.303/t(0.738)

0.131 = 1.6996/t

t =  1.6996/0.131

t = 12.97 years

t = 13 years(to the nearest whole number)


Related Questions

Select The on that most applys


Will mark brainliest

Answers

Answer:

A and b

Explanation:

A is the answer hope this helped !

I need help on this please

Answers

Answer:

The answer is c

Explanation:c


Which of the following terms best describes an atom which is chemically unreactive?
A static
B full
C satisfied
D invert

Answers

Option D is the correct alternative.

We have a chemically unreactive element.

We have to determine which term best describes this atom.

What is Reactivity ?

Reactivity in chemistry is the impulse for which a chemical substance undergoes a chemical reaction, either by itself or with other materials.

According to the question -

An atom that that does not react with the other atoms belongs to those elements which are chemically unreactive or inert elements. The reason behind their inertness is their completely filled outermost shell which can accommodate a maximum of 8 electrons which is as shown by their electronic configuration -  1s²2s²2p⁶. Hence, they are highly stable and don't react with other elements. Ex - Helium, Argon, Neon etc.

Hence, Option D is the correct alternative.

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Determine the mass of 2.86 mole Co(NH3)6Cl3

Answers

Answer:

765 g Co(NH₃)₆Cl₃

General Formulas and Concepts:

Reading the Periodic Table of Elements

Explanation:

Step 1: Define

2.86 mol Co(NH₃)₆Cl₃

Step 2: Define conversions

Molar Mass of Co - 58.93 g/mol

Molar Mass of N - 14.01 g/mol

Molar Mass of H - 1.01 g/mol

Molar Mass of Cl - 35.45 g/mol

Molar Mass of Co(NH₃)₆Cl₃ - 58.93 + 6(14.01) + 18(1.01) + 3(35.45) = 267.52 g/mol

Step 3: Dimensional Analysis

[tex]2.86 \ mol \ Co(NH_3)_6Cl_3(\frac{267.52 \ g \ Co(NH_3)_6Cl_3}{1 \ mol \ Co(NH_3)_6Cl_3} )[/tex] = 765.107 g Co(NH₃)₆Cl₃

mol Co(NH₃)₆Cl₃ and mol Co(NH₃)₆Cl₃ cancel outWe are left with grams (mass)

Step 4: Simplify

We are given 3 sig figs. Follow sig fig rules.

765.107 g Co(NH₃)₆Cl₃ ≈ 765 g Co(NH₃)₆Cl₃

What cause a earthquake

Answers

An earthquake is caused by a sudden slip on a fault. ... When the stress on the edge overcomes the friction, there is an earthquake that releases energy in waves that travel through the earth's crust and cause the shaking that we feel. In California there are two plates - the Pacific Plate and the North American Plate.

Answer:

Sudden motions in Earths mantle causeing the crust to shift.

Explanation:

Which class of organic compound is most likely to be used in anesthetics?
ether
ester
alkyl halide
carboxylic acid

Answers

Answer:

A.

ether

Explanation:

i got it right on edg 2020 and they use ether in pokemon games to heal PP so that makes logical sense lol

The class of organic compounds that are used in anesthetics is:

A. Ether

It is a functional group consisting of C and O.

What are Anesthetics?

Anesthetics are an assorted gathering of medications with especially unique synthetic designs, going from basic inorganic atoms like nitrous oxide to additional perplexing natural specialists.

Organic compound is one that contains a bond with a carbon particle. In ethers, the practical gathering that is available is C=O. Ether, as a fluid, discharges fumes that are breathed in. Another very powerful fluid sedative is propofol, controlled intravenously.

Thus, correct option is A.

Find more information about Organic compound here:

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Determine the pressure of a 6.4L sample of oxygen gas at 300K and 100KPa, after the gas is compressed to 2.40L at 900K.

Answers

The pressure : 800 kPa

Further explanation

Boyle's law and Gay Lussac's law  

[tex]\tt \dfrac{P_1.V_1}{T_1}=\dfrac{P_2.V_2}{T_2}[/tex]

P1 = initial gas pressure (N/m² or Pa)  

V1 = initial gas volume (m³)  

P2 = gas end pressure  

V2 = the final volume of gas  

T1 = initial gas temperature (K)  

T2 = gas end temperature  

The pressure after the gas is compressed :

[tex]\tt \dfrac{100\times 6.4}{300}=\dfrac{P_2\times 2.4}{900}\\\\P_2=800~KPa[/tex]

Atmospheric pressure is the sum of the pressure created by all gases in the
atmosphere. How does the atmospheric pressure change as you move
from places of high elevation to low elevation?
Your answer

Answers

Answer:

high less air cause there is no trees and lower is the same

Explanation:

HELP! will mark brainliest if gotten right

Answers

the answer is B i think

14. Which of the following groups is most at risk for developing this disease?
a) children born to mothers with dark skin, living far from the equator
b) adults with dark skin who live close to the equator
c) children born to mothers with light skin who live close to the equator

Answers

Answer: c

Explanation: built different

If you wanted to change the polarity of hydrogen bromide (HBr) by substituting the bromine by a different atom. Which atom would increase the polarity of the molecule?

Answers

Answer:

Chlorine

Explanation:

The Polarity of an atom is characterized as the dipole to dipole intermolecular forces between the slightly positively-charged end of one molecule to the negative end of another or the same molecule. Thus, the 'chlorine' atom would help in enhancing the polarity of hydrogen bromide(HBr) with 3.16 electronegativity as we know, the electronegativity increases if we move upwards in the periodic table.

Jai was measuring the radioactivity of different radioactive isotopes. Isotope A had a starting radioactive level of 50 g, and after 4 days it measured at 30 g. Isotope B had a starting radioactive level of 75 g, and after 4 days it measured at 25 g. Which best explains the isotopes?

Isotope A has a shorter half-life than Isotope B.
Isotope A has a longer half-life than Isotope B.
Isotope A has half the half-life of Isotope B.
Isotope A has twice the half-life of Isotope B.

Answers

Answer:

b

Explanation:

I did the test mark the brianlyes byyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy

Answer:

Its the second one (B)

Explanation:

Marki the person that answerd first brainliest :)

Rising greenhouse gases. Climate change. Rising energy costs. Declining fossil fuels reserves. With the arguments against fossil fuels continuing to pile up it is no wonder people have latched onto nuclear power as an attractive solution....

1. What is nuclear fission? ________________________________________________________________________________
2. What is nuclear fusion? ________________________________________________________________________________
3. What happens when the energy from splitting an atom is released all at once? _____________________________________
4. What element is used in nuclear power plants as fuel? ________________________________________________________
5. What dangerous byproduct is produced by nuclear power plants? _______________________________________________
6. Describe THREE benefits of using nuclear power: ___________________________________________________________, _____________________________________________________, and __________________________________________
7. What is the function of the cooling towers of the nuclear reactor shown below? _____________________________________

Answers

Answer:

Nuclear Fission is a nuclear reaction or a Radioactive decay progress in which the necleus of an atom splits into two or more smaller, lighter neclei

If you triple the force on an object , the acceleration will

a
reduced by 1/3
b
double
c
tripled
d
halve

Answers

Answer:

C triple

Explanation:

please crown me

The study of fossil mammals is:
micropaleontology
invertebrate paleontology
vertebrate paleontology
paleobotany
these are the chocies

Answers

Answer:

The study of fossil mammals comes under vertebrate paleontology

(aka vertebrate paleontology)

Answer:

The study of fossil mammals comes under vertebrate paleontology.

Explanation:

Paleontology is the study of fossils which tries to explain the evolution of organisms, their environment and interactions with each other. The various sub divisions of paleontology are vertebrate paleontology, invertebrate paleontology , micropaleontology, paleobotany, palynology etc.

The study of vertebrate fossils, from primitive fishes to the immediate ancestors of modern mammals is known as vertebrate paleontology. Invertebrate paleontology deals with the study of invertebrate animal fossils, such as molluscs, echinoderms, arthropods and annelid worms. Paleobotany studies fossil plants which includes the study of fossil algae and fungi in addition to land plants.  Micropaleontology is the study of microscopic fossil organisms, regardless of the group to which they belong.

_________________________________________________________

Brainliest? I just want to move up a level in Brainly, so please. Lol not trying to sound so desperate.

please help ASAPPP
will mark brainliest!!!

Answers

Greetings!______________________________________Answer:[tex]OH^{-1}[/tex]WHY IS OPTION A NOT POLYATOMIC?

The polyatomic ions are those ions which has more than two atoms involved such as the other options than OH^-1 in the question. The OH^-1 ion is the diatomic ion because it has only 2 atoms

______________________________________HOPE IT HELPS!

what happens to the electronegatity when you go from top to bottom on the periodic table?

Answers

Answer:

It decreases

Explanation:

As you go down a group from top to bottom, the electronegativity decreases. Across a period, electronegativity increases from left to right.

Electronegativity is the tendency with which the atoms of the element attracts valence electrons in a chemical bond. The more electronegative an element is, the stronger its affinity for electrons. Electronegativity values less than 2 shows an element is a metal. Metals are generally electropositive.

Use the equation below to solve the problem that follows.

2H2 (g) + O2 (g) → 2H2O (g)

When David reacts 13.8 grams of hydrogen gas with excess oxygen, 87.0 grams of water are formed. Calculate his percent yield of water.

Im very loss with this question

Answers

Percent yield of water : 70%

Further explanation

Reaction

2H₂ (g) + O₂ (g) → 2H₂O (g)

mol H₂(MW= 2 g/mol) :

[tex]\tt \dfrac{13.8~g}{2~g/mol}=6.9~mol[/tex]

mol H₂O = mol H₂ = 6.9

mass H₂O(theoretical) :

[tex]\tt 6.9\times 18~g/mol=124.2~g[/tex]

[tex]\tt \%yield=\dfrac{actual}{theoretical}\times 100\%\\\\\%yield=\dfrac{87}{124.2}\times 100\%=70\%[/tex]

True or False: Plants don't have brains, but they still adapt to their environments.

Answers

Answer:

True

Explanation:

I just took that last year, and got a100%

True, Plants don't have brains, but they still adapt to their environments.

What is adaptation?

Adaptation is a process where they are changing their nature to suit the environment.

We have seen that plants do adaptation according to the environment, as in the summer season their leaves are hanging down but in the rainy season they show blossoms and green leaves. So, according to the environment for the survival and reproduction they adapt their body.

Hence, plants have no brains, but they still adapt.

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Explain What is an elementary reaction and how is it related to a reaction mechanism

Answers

Answer:

The sequence of individual steps, or elementary reactions, by which reactants are converted into products during the course of a reaction is called the reaction mechanism. The overall rate of a reaction is determined by the rate of the slowest step, called the rate-determining step.

Explanation:

Explain the relationship between protons and ionization energy

Answers

The more protons in the nucleus, the stronger the attraction of the nucleus to electrons. This stronger attraction makes it more difficult to remove electrons. Within a group, the ionization energy decreases as the size of the atom gets larger.

need help asap!!!!
will mark brainliest!!!

Answers

We can verify the properties as follows;

1) Sour taste - Put some soda on your tongue

2) Corrode metals - Put a little soda on a clean metal surface

3) Effect on Litmus paper - Dip a blue litmus paper in soda

4) Electrolysis - Add two electrodes to soda and connect a battery.

Does Soda show acidic properties?

Soda, specifically carbonated beverages like cola or soda pop, typically exhibits acidic properties. The acidity of soda is primarily due to the presence of carbonic acid (H₂CO₃), which forms when carbon dioxide gas (CO₂) dissolves in water.

When carbon dioxide is dissolved in water under high pressure, it forms carbonic acid through the following reaction:

CO₂ + H₂O ⇌ H₂CO₃

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How much energy is required to raise the temperature of 0.2 kg of aluminum from 15°C to 18°C? (Refer to table of specific heat values.)​

Answers

the answer is B. 538J

The amount of energy which  is required to raise the temperature of 0.2 kg of aluminum from 15°C to 18°C is 49,545 J.

How do we calculate absorbed energy?

Amount of energy absorbed by any material will be calculated by using the below equation:

Q = mcΔT, where

m = mass of aluminum = 0.2 kg

c = specific heat of aluminum = 897 J/kg.K

ΔT = change in temperature = 18 - 15 = 3°C = 276.15 K

On putting these value on the above equation, we get

Q = (0.2)(897)(276.17) = 49,544.89 = 49,545 J

Hence required amount of energy is 49,545 J.

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Calculate the number of moles in each of the following masses.

1. 0.039 g of palladium
2. 8200 g of iron

Calculate the mass in grams of each of the following amounts:

3. 1.002 mol of chromium
4. 550 mol of aluminum

Calculate the number of atoms in each of the following amounts

5. 17.0 mol of germanium

Answers

Answer:

1. 3.7 * 10^-4 mol Pd

2. 146.8 mol Fe (or 150 mol Fe if sig fig are required)

3. 52.10 g Cr

4. 14839 g Al (or 15000 g Al if sig fig are required)

5. 1.02  * 10^25 atoms Ge

Explanation:

Water is the only substance that can dissolve polar solutes. True or False?

Answers

Answer:

false!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Explanation:

Can someone tell me about kinetic, potential, and gravitational energy?

Answers

Answer:

the internet can teach you alot about all 3 things

Explanation:

Answer:

if you go on YT and search  kinetic, potential, and gravitational energy their will be a bill nye vid that is very informational on the topic at hand!!!

Explanation:

hope this helps!!

An atom with 4 protons and 4 neutrons Is called?

Answers

Answer:

i'm pretty sure it's beryllium

Explanation:

Answer:

Beryllium

Explanation:

the atomic number is equal to protons

What is one way land helps reduce the force of hurricane as it moves inland

Answers

Answer:

because they are fueled by evaporation from warm ocean water, which dry land surfaces do not provide.

Explanation:

Answer: Other person was wrong correct answer is Land filters the water forced up from the sea by the wind :)

Explanation:

Pls Help! one multiple-choice question for 13 points and brainliest!

Where does the energy from sunlight go in photosynthesis?
a) covalent bonds in carbon dioxide
b) covalent bonds in glucose
c) covalent bonds in oxygen
d) polar covalent bonds in water

Answers

Answer:

B

Explanation:

They use energy from sunlight to synthesise glucose from carbon dioxide and water.  

Which is the first step that geologists must do to compare rock layers at distant locations?

find the absolute age of rocks at both locations
compare a layer at one location to layers at other locations
identify index fossils in one or more layers at one location
collect fossils from different locations to study the organisms’ lifestyles

Answers

Answer: Comparing rock layers in distant places can be a challenge for geologists since these layers may have different environmental factors that caused different transformations in them.

Therefore, when it is necessary to establish a comparison between layers of rocks in different ligands, geologists must establish steps to make an efficient comparison and have results consistent with reality. To do this, they must first compare a layer in one location with layers in other locations, assign relative age to a layer in one location, and identify index fossils in one or more layers in one location.

Answer:

C

Explanation:

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