Answer:
simple cations (monatomic cations of elements of only one possible charge)
Explanation:
Simple cations (monatomic cations of elements of only one possible charge) are named using the unmodified element name and adding the word "ion"
For example, the Na+ is named the sodium ion.
An atom or molecule with a net electric charge as a result of the loss or gain of one or more electrons is known as an ion.
carbon dioxide is a non-polar molecule true or false
Answer:
True
Explanation:
Due to the arrangement of the molecule, a carbon dioxide molecule is non-polar.
To determine the concentration of a sample of calcium hydroxide, 1.45M HCl is added drop-wise using a burst. Write the balanced net ionic equation for the acid-base reaction.
Answer:
H^+(aq) + OH^-(aq) —> H2O(l)
Explanation:
We'll begin by writing the balanced equation for the reaction.
2HCl(aq) + Ca(OH)2(aq) —> CaCl2(aq) + 2H2O(l)
Ca(OH)2 is a strong base and will dissociates as follow:
Ca(OH)2(aq) —> Ca^2+(aq) + 2OH^-(aq)
HCl is a strong acid and will dissociates as follow:
HCl(aq) —> H^+(aq) + Cl^-(aq)
Thus, In solution a double displacement reaction occurs as shown below:
2H^+(aq) + 2Cl^-(aq) + Ca^2+(aq) + 2OH^-(aq) —> Ca^2+(aq) + 2Cl^-(aq) + 2H2O(l)
To get the net ionic equation, cancel out Ca^2+ and 2Cl^-
2H^+(aq) + 2OH^-(aq) —> 2H2O(l)
H^+(aq) + OH^-(aq) —> H2O(l)
Coral reefs support more species per unit area than any other marine
environment on Earth. What role do coral reefs play in the health of the
biosphere?
A. Coral reefs tend to drain nearby wetlands of stagnant water.
B. Their productive organisms play a major role in nutrient recycling.
C. Their colorful organisms attract millions of tourists each year.
D. Coral reefs require very specific environmental conditions.
SUBMIT
Answer:
B. Their productive organisms play a major role in nutrient recycling.
Explanation:
Coral reefs contain photosynthetic algae that help coral reefs in processing nutrients and contribute in the nutrient cycle.
The process of photosynthesis in corals leads to carbon fixing in which corals transform, carbon dioxide, into organic carbon. carbon fixing property allows corals to become primary producers.
Dissolve organic matter produced by corals is consumed by several organisms such as crabs, worms, fish, and snails.
Hence, coral reefs maintain the flow of energy and nutrient cycle in the biosphere and the correct option is B.
If complications arise after cataract surgery, the ophthalmologist will use a Nd:YAG laser to perform a posterior capsulotomy. If the wavelength of the laser used is 1064 nm (infrared), and the pulse duration is 2.00 x 10–6 s whose energy is 0.245 J per pulse, how many photons are produced in each pulse?
Answer: 1.311 × 10^18 photons are produced in each pulse
Explanation: Please see the attachments below
During which stage of the water cycle could water enter the atmosphere as a gas? A. transpiration B. precipitation C. accumulation D. condensation
Answer: Transpiration---A
Explanation: Transpiration is the process in the water cycle whereby plant loose(excess) water by evaporation through the stomata of their leaves since not all water absorbed by the root is actually used for growth in plants.In order to allow the intake of carbon-dioxide, water must exit the leaves through transpiration which then provides the plant with cooling, rigidity and maintaining the overall water balance of the plant.
A student has an unknown sample of solution X. This solution is placed in a 1.00 cm wide cuvet and inserted into the spectrometer, producing an absorbance reading of 0.275 at a wavelength of 525.0 nm. What is the concentration of solution X in the unknown sample
Answer:
The concentration of the sample is 3.564x10⁻³M.
Explanation:
Using Lambert-Beer law, absorbance of a sample is directely proportional to its concentration.
The general graph of the absorbance of the standards with different concentrations is:
Y = 75.9X + 0.0045
R² = 0.9946
Where Y is the absorbance of the sample and X its concentration in mole/L.
If a solution has an absorbance of 0.275:
0.275 = 75.9X + 0.0045
0.2705 = 75.9X
3.564x10⁻³M = X → The concentration of the sample.
Acetic acid and ethanol react to form ethyl acetate and water.If 94.0 mmol of C2H5CO2CH3 are removed from a flask containing a mixture of HCH3CO2, C2H5OH, C2H5CO2CH3 and H2O at equilibrium, then following questions are to be answered. 1. What is the rate of the reverse reaction before any C2H5CO2CH3 has been removed from the flask?2. What is the rate of the reverse reaction just after the C2H5CO2CH3 has been removed from the flask?3. What is the rate of the reverse reaction when the system has again achieved equilibrium?4. How much less C2H5CO2CH3 is in the flask when the system has again reached equilibrium?
Answer:
Explanation:
The equation for the react between Acetic acid and ethanol to form ethyl acetate and water is :
[tex]HCH_3CO_2_{(aq)}+C_2H_5OH_{(aq)} \to C_2H_5CO_2CH_3_{(aq)} + H_2O_{(l)}[/tex]
Imagine if 94.0 mmol of [tex]C_2H_5CO_2CH_3[/tex] are removed from a flask; Then:
We are to answer the following questions:
1. What is the rate of the reverse reaction before any [tex]C_2H_5CO_2CH_3[/tex] has been removed from the flask?
The reaction above is called an esterification reaction;
So the rate of reverse reaction before any [tex]C_2H_5CO_2CH_3[/tex] is removed is greater than zero and equal to forward reaction rate.
2. What is the rate of the reverse reaction just after the [tex]C_2H_5CO_2CH_3[/tex] has been removed from the flask?
Just after the [tex]C_2H_5CO_2CH_3[/tex] has been removed from the flask, the rate of the reverse reaction is greater than zero but less than forward reaction rate.
3. What is the rate of the reverse reaction when the system has again achieved equilibrium?
When the system has again achieved equilibrium, the rate of the reverse reaction is greater than zero and equal to forward reaction rate because we it has achieved the equilibrium, hence, the reaction tends to proceed in the forward direction.
4. How much less [tex]C_2H_5CO_2CH_3[/tex] is in the flask when the system has again reached equilibrium?
The [tex]C_2H_5CO_2CH_3[/tex] in the flask when the system has again reached equilibrium is lesser by 94.0 mmol as given right from the question
An unknown compound, B, has the molecular formula C7H12. On catalytic hydrogenation 1 mol of B absorbs 2 mol of hydrogen and yields 2-methylhexane. B has significant IR absorption band at about 3300 and 2200 cm-1. Which compound best represents B?
a. 5-methyl-1,3-hexadiene
b. 5-methyl-1-hexyne
c. 3-methyl-1-hexyne
d. 5-methyl-2-hexyne
e. 2-methyl-1,5-hexadiene
Answer:
B and D
Explanation:
If we use the info given we have a band a 3300 cm-1 and 2200 cm-1 this indicates that we have an alkyne functional group. Additionally, the hydrogenation of the unknown molecule will consume two moles of hydrogens this fits with the 2 pi bonds in the alkyne functional group. So, we can discard "a" and "e". The product of this hydrogenation is 2-methylhexane therefore we can discard c because the methyl group is placed on carbon 3. Structures b and d can work.
See figure 1
I hope it helps!
A teacher has asked some groups of students to investigate the relationship between the organ systems of the human body. One group of students made the argument that many of the systems are related to each other. How can the illustration be used to support this argument?
Choose the correct answer.
The nervous system produces signals that control all of the body’s muscle movements.
The skeletal system provides the physical support for the respiratory system.
The digestive system breaks down food into nutrients that are transported by the circulatory system.
The endocrine system sends hormones to target organs in response to signals from the reproductive system.
Answer: The digestive system breaks down food into nutrients that are transported by the circulatory system.
Explanation:
An organ system includes the organs which are linked to one another to perform a physiological function in the body of the organism. The digestion is a complex process in which the food is being broken down into sub-components so that it can be assimilated in the body. The digestive system involves the multiple organs like mouth, esophagus, stomach, intestines and others. The food being digested is absorbed in the bloodstream, which circulate in the vital organs of the body like lungs, heart, vascular system hence, the blood becomes the part of the circulatory system.
Thus it can be said that the argument of children that the two systems are related is justified by the digestive and circulatory system of the body.
3 Pieces of Key Information elements, compounds, mixtures also state a real world example of elements, compounds, mixtures and lastly why is elements, compounds, mixtures are important
Answer:
Element and compounds are the pure substances but mixture is not a pure substance.
Explanation:
Element and compounds are the pure substances in which element comprise of only one atom while compound is formed by the chemical combination of more than one element in a fixed ratio by mass while mixture is also made up of more that one substances but they are combine physically not chemically. Elements, compounds, mixtures are very important because all the materials we used in our daily life are formed from elements, compounds and mixtures.
If 200.4g of water is mixed with 101.42g of salt the mass of the final solution would be reported as
Answer:
301.8 g
Explanation:
We prepare a solution with 200.4 g of water (solvent) and 101.42 g of salt (solute). The mass of the solution is equal to the sum of the mass of the solvent and the mass of the solute.
m(solution) = m(solute) + m(solvent)
m(solution) = 200.4 g + 101.42 g
m(solution) = 301.8 g (we round-off to one decimal according to the significant figures rules)
What is the reactant(s) in the chemical equation below?
2Al(s) + 2NaOH(aq) + 2H2O()
2NaAlO2(aq) + 3H2(9)
A. 2Al(s) + 2NaOH(aq) + 2H200)
B. 2NaAlo2(aq) + 3H2(g)
C. 2Al(s)
D. 3H2(g)
Answer:
A
Explanation:
They are all found in the reactants side
Gravity on Earth is 9.8 m/s2, and gravity on the Moon is 1.6 m/s2.
so if the mass of an object on earth is 40 kilograms what is the mass on the moon.
and how much does it way
Answer:
Mass is the same but it weights 64 Newtons
Explanation:
First of Mass is the same in any sort of gravity. Now let's calculate weight
W = MG
where W = Weight
M = Mass
G = Gravity
W = (40kg)(1.6)
W = 64
Sorry for the spelling mistakes, hope this helps
Answer:6.61kilo
Explanation: fdfv
Aspirin is usually packaged with
A. acetic anhydride
B. salicylic acid
C. buffering agents
Answer:
Aspirin is usually packaged with C. buffering agents.
Explanation:
Which option describes a similarity and a difference between isotopes of an element? A. same atomic number; different number of protons B. same number of protons; different atomic number C. same atomic number; different mass number D. same mass number; different atomic number E. same number of neutrons; same number of protons
Answer:
c
Explanation:
In this problem, you will use Lenz's law to explore what happens when an electromagnet is activated a short distance from a wire loop.
You will need to use the right-hand rule to find the direction of the induced current. When the switch is open, which of the following statements about the magnetic flux through the wire loop is true? Assume that the direction of the vector area of the wire loop is to the right.
A) There is no magnetic flux through the wire loop.
B) There is a positive flux through the wire loop.
C) There is a negative flux through the wire loop.
Answer:
The correct answer is Option A (There is no magnetic flux through the wire loop.)
Explanation:
Magnetic flux measures the entire magnetic field that passes through the wire loop.
The right hand rule can be demonstrated on how magnetic flux is generated through the moving current in the wire loop. The magnetic flux through the wire loop will decrease as it moves upward through the magnetic field region.
If the direction of the vector area of the wire loop is to the right, and the switch is closed, it will push the magnetic flux to the right which will now be increased due to an equal increase in the current in the wire loop. But, when the switch is open, this will halt the movement of current through the wire loop thus affecting the generation of magnetic field. This would make the magnetic flux to be zero.
The statement related to the magnetic flux is option A i.e. no magnetic flux is there.
What is magnetic flux?It determined the overall magnetic field that should be passed via the looping of the wire. here the right-hand rule represent how the magnetic flux should be created via the movement of the current.
Also, it should be decreased in the case when it should be moved upward. Also, in the case when the direction of the vector area should be right so the switch should be closed.
Therefore, the option A is correct.
Learn more about magnetic here: https://brainly.com/question/18704022
What is the mass of 3.75 moles of NaCI? ( Na= 22.99g/mol, CI= 35.45 g/mol)
Answer:
219.15 grams
Explanation:
What is the mass of 3.75 moles of NaCI? ( Na= 22.99g/mol, CI= 35.45 g/mol)
Mole of Na = 22.99g
Mole of Cl = 35.45g
For NaCl we have ratio of 1:1, so we have 1 Na for every Cl
So we just add the two together to get the molar mass of NaCl which is
22.99 + 35.45 = 58.44g/mol
And we know we have 3.75 moles of NaCl so we multiply that by the molar mass of NaCl to get our answer
3.75 x 58.44 = 219.15grams
g Reduction involves the A) loss of neutrons, gain of electrons, and an increase in oxidation state. B) loss of neutrons. C) increase in oxidation state. D) gain of electrons and an increase in oxidation state. E) gain of electrons.
Answer:
E. Gain of electrons
Explanation:
A reduction reaction is one part of the two concurrent reactions that take place in a redox (reduction-oxidation) reaction.
During reduction, an atom gains electrons from a donor atom, and it's oxidation number becomes smaller.
Option A is wrong because reduction does not increase oxidation state nor are neutrons involved
Option B is wrong because reduction is not a nuclear reaction (does not involve the nucleons)
Option C is wrong because reduction leads to reduction in oxidation state
Option D is wrong leads to a reduction in oxidation state when electrons are gained
Option E is correct because reduction involves gain of electrons
what would happen if you place two positive charges next to each other and let go. would they attract, stay still, or they would repel
Answer:
they would repel
Explanation:
unlike charges attract while like ones repel.
5. Rosalind Franklin was a key figure in the discovery of the structure of DNA, yet she
was not included in the Nobel Prize which was awarded to Watson and Crick. Carry out
some research to find out how she contributed to this work and use the space below
to write up your findings
Answer:
Explanation:
Search for "Rosalind Franklin: DNA's unsung hero - Cláudio L. Guerra" which basically summarizes what Rosalind did and how we was snubbed from receiving the noble prize even though she had vast and critical evidence to highlight the structure of DNA. You can look for more sources but I can tell you a quick recap:
Rosalind Franklin was born in an era where women scientists or workers were very uncommon and they were even discriminated and looked down upon. After her phD., she was working to find the structure of DNA and soon she was able to form an x-ray image of it. However, her lab colleague took the picture and showed it to other scientists (Watson and Crick) without the knowledge or permission of Rosalind. Here Rosalind was working on analyzing her data and on other part of world Watson and Crick were doing the same. Based on Watson and Crick's analysis, they came up with the correct structure of DNA and soon Rosalind got done as well. Both submitted their paper to journal, however, the journal placed Watson and Crick paper before Rosalind (making it look like Rosalind just confirmed what Watson and Crick proposed). This made it look like Watson and Crick were geniuses behind DNA structure whereas, in reality, it was Rosalind. She would have received Nobel Prize but she died of Cancer and Nobel prizes are not awarded to dead people.
What occurs when potassium reacts with bromine to form potassium bromide?
1) Electrons are shared and the bonding is ionic.
2) Electrons are shared and the bonding is covalent.
3) Electrons are transferred and the bonding is ionic
4) Electrons are transferred and the bonding is covalent.
Fill in the blank: If an atom is in column V (or 15), it will most likely ____________ to fulfill the octet rule.
Gain 3 electrons
Lose 5 electrons
Gain 5 electrons
Lose 5 protons
Gain 3 protons
Answer:
If an atom is in column V (or 15), it will most likely gain 3 electrons to fulfill the octet rule.
Explanation:
The octet rule defines the property that atoms have to complete their last energy level with eight electrons to achieve stability through an ionic, covalent or metallic bond.
The pair of electrons that are transferred or gained belong to the last shell of the atom. If an atom is in column V (or 15), it means that it has 5 electrons in its last shell. So an atom in this group is more likely to gain 3 electrons to achieve stability than to lose the 5 electrons it has.
If an atom is in column V (or 15), it will most likely gain 3 electrons to fulfill the octet rule.
A. Gain 3 electrons
What does Octet rule say?The octet rule defines the property that atoms have to complete their last energy level with eight electrons to achieve stability through an ionic, covalent or metallic bond.
The pair of electrons that are transferred or gained belong to the last shell of the atom. If an atom is in column V (or 15), it means that it has 5 electrons in its last shell. So an atom in this group is more likely to gain 3 electrons to achieve stability than to lose the 5 electrons it has.
Thus, correct option is A.
Find more information about Octet rule here:
brainly.com/question/865531
A maple tree could be studied in many fields of science. What aspects of a maple tree might be studied in chemistry?
Answer:
Chemical reactions, kinetics, organic chemistry
Explanation:
You might study the chemical reaction, learn about the differences between products and reactants, about delta H and exothermic and endothermic reactions. You may also study Kinetics by studying the rates of reactions with certain chemicals in a maple's enzymatic processes.
Another thing that you might learn about is organic chemistry. The glucose molecules, carbohydrates, lipids, nucleic acids, all have a structure based on the Carbon atom. You can learn about the specific structures of some chemicals that are involved in photosynthesis and simple hydrocarbons that are involved in photosynthetic/bio-synthetic pathways.
There's probably a lot more - but these are the most basic things I could think of.
Calculate the pH of a 0.020 M H2CO3 solution. At 25 °C, Ka1 = 4.3 × 10-7. H2CO3(aq) + H2O(l) ↔ H3O+(aq) + HCO3-(aq)
Answer:
Explanation:
H₂CO₃(aq) + H₂O(l) ↔ H₃O⁺(aq) + HCO₃⁻(aq)
Let d be the degree of dissociation
.02( 1-d ) .02d .02d
Dissociation constant Ka₁ is given
4.3 x 10⁻⁷ = .02d x .02d / .02( 1-d )
= .004 d² / .02 ( neglecting d in denominator )
= .02 d²
d² = 215 x 10⁻⁷
d = 4.636 x 10⁻³
= .004636
concentration of H₃O⁺
= d x .02
= .004636 x .02
= 9.272 x 10⁻⁵
pH = - log [ H₃O⁺ ]
= - log ( 9.272 x 10⁻⁵ )
5 - log 9.272
= 5 - .967
= 4.033 .
Nitrogen forms more oxides than any other element. The percents by mass of in three different nitrogen oxides are (1) (II) and (III) 25.94 For each compound, determine (a) the simplest whole-number ratio of to and (b) the number of grams of oxygen per 1.00 of nitrogen.
Complete question;
Nitrogen forms more oxides than any other element. The percents by mass of N in three different nitrogen oxides are (|) 46.69%;(II) 36.85 %; (III) 25.94%. For each compound, determine (a) the simplest whole-number ratio of N to O, and (b) the number of grams of oxygen per 1.00 g of nitrogen.
Answer:
a. (i) The ratio is 1:1 , the formula = NO (ii)The ratio is 1 : 1.5 which is 2 : 3, the formula = N₂O₃ (iii) The ratio is 1 : 2.5 which is 2:5 , the formula = N₂O₅
b. (i)number of grams of oxygen = 53.31/46.69 = 1.14 g
(ii)number of grams of oxygen = 63.15/36.8 = 1.71 g
(iii)number of grams of oxygen = 74.06/25.94 = 2.855 g
Explanation:
a.
(i) The percentage by mass of the nitrogen in Nitrogen oxide (i) is 46.69% which is taken as 46.69 grams . Since the other element is oxygen the mass of oxygen will be 100 - 46.69 = 53.31 grams.
The relative atomic mass of Nitrogen and oxygen is 14 amu and 16 amu respectively.
Therefore, to know the whole number ratio of N and O we find the number of moles.
number of moles of N = 46.69/14 = 3.335
number of moles of O = 53.31/16 = 3.332
The ratio is 1:1 , the formula = NO
(ii)
number of moles of N = 36.85/14 = 2.632
number of moles of O = 63.15/16 = 3.947
The ratio is 1 : 1.5 which is 2 : 3, the formula = N₂O₃
(iii)
number of moles of N = 25.94/14 = 1.85
number of moles of O = 74.06/16 = 4.63
The ratio is 1 : 2.5 which is 2:5 , the formula = N₂O₅
b.
(i) 46.69 g of nitrogen = 53.31 g of oxygen
1 g of nitrogen = ? of Oxygen
number of grams of oxygen = 53.31/46.69 = 1.14 g
(ii)
Using similar method in b(i)
number of grams of oxygen = 63.15/36.8 = 1.71 g
(iii)
Using similar method in b(i)
number of grams of oxygen = 74.06/25.94 = 2.855 g
WILL GIVE BRAINLIEST!!!!! will give brainliest!!!!! ---------Write the molecular equation, complete ionic equation and net ionic equation of Barium nitrate reacting with potassium carbonate.
Answer:
Molecular:
Ba(NO3)2 + K2CO3 -> BaCO3 + 2KNO3
Complete ionic:
Ba2+ + 2NO3- + 2K+ + CO3 2- -> BaCO3 + 2K+ + 2NO3-
Net ionic:
Ba2+ + CO3 2- - > BaCO3
Explanation:
Molecular consists of all species reacting.
Complete ionic consists of all ionic species (ex. K+, NO3-) separated, as well as any compounds that didn't dissociate into ions (BaCO3 doesn't dissolve).
Net ionic doesn't include spectator ions (in this case, nitrate and potassium) and only species that aren't present on both sides of the arrow (barium and carbonate become a solid precipitate, so the ions aren't present as products, making them appear in the net ionic equation).
What is the equilibrium constant for the following reaction:HCO2H(aq) + CN–(aq) HCO2–(aq) + HCN(aq)Does the reaction favor the formation of reactants or products? The acid dissociation constant, Ka, for HCO2H is 1.8 x 10–4and the acid dissociation constant for HCN is 4.0 x 10–10.(A) K = 1.00. The reaction favors neither the formation of reactants nor products.(B) K = 2.2 x 10–6. The reaction favors the formation of products.(C) K = 2.2 x 10–6. The reaction favors the formation of reactants.(D) K = 4.5 x 105. The reaction favors the formation of products.(E) K = 4.5 x 105. The reaction favors the formation of reactants.
Answer:
(D) K = 4.5 x 10⁵. The reaction favors the formation of products
Explanation:
HCOOH + CN⁻ ⇆ HCOO⁻ + HCN
K = [HCOO⁻] [ HCN ] / [ HCOOH] [ CN⁻]
HCOOH ⇄ H ⁺ + COO⁻
K₁ = [ H⁺] [ COO⁻ ] / [HCOOH ]
HCN ⇆ H⁺ + CN⁻
K₂ = [ H⁺] [ CN⁻] / [ HCN ]
K₁ / K₂
= [ H⁺] [ COO⁻ ] / [HCOOH ] X [ HCN ] / [ H⁺] [ CN⁻]
= [ COO⁻ ][ HCN ] / [HCOOH ] [ CN⁻]
= K
K = K₁ / K₂
= 1.8 x 10⁻⁴ / 4 x 10⁻¹⁰
= 4.5 x 10⁵
So equilibrium constant of the reaction
HCOOH + CN⁻ ⇆ HCOO⁻ + HCN
is very high . Hence reaction favours the formation of product.
option (D) is correct.
Use bond energies to calculate ΔHrxn Δ H r x n for the reaction. 2H2(g)+O2(g)→2H2O(g) 2 H 2 ( g ) + O 2 ( g ) → 2 H 2 O ( g )
Answer:
[tex]\large \boxed{\text{-486 kJ}}[/tex]
Explanation:
You calculate the energy required to break all the bonds in the reactants.
Then you subtract the energy needed to break all the bonds in the products.
2H₂ + O₂ ⟶ 2H-O-H
Bonds: 2H-H 1O=O 4H-O
D/kJ·mol⁻¹: 436 498 464
[tex]\begin{array}{rcl}\Delta H & = & \sum{mD_{\text{reactants}}} - \sum{nD_{\text{products}}}\\& = & 2 \times 436 +1 \times 498 - 4 \times 464\\&=& 1370 - 1856\\&=&\textbf{-486 kJ}\\\end{array}\\\text{The enthalpy of reaction is $\large \boxed{\textbf{-486 kJ}}$}.[/tex]
Nitrogen is a group 15 element. What does being in this group imply about the structure of the nitrogen atom?
O A. Nitrogen has 15 valence electrons.
OB.
Nitrogen has 15 neutrons.
OC. Nitrogen has 5 valence electrons.
D.
Nitrogen has 5 neutrons.
Answer:
D. Nitrogen has 5 valence electrons.
Explanation:
Nitrogen is an element in group 5A of the periodic table. Elements in group 5A all contain just 5 valence electrons. (Electrons in the outer shell).
**Elements are organized into these groups in a periodic table based on the number of valence electrons which determines their charge. (Does not apply to transition metals)
The decay of a radioactive material is monitored using a Geiger counter. At the start, the count rate is 2000 decays/minute. Four hours later the decay rate is 500 counts/min. What is the half-life of the material?
Answer:
The half-life of the material is 2 years
Explanation:
Given;
initial count rate = 2000 decays/minute
final count rate = 500 counts/min
decay time = Four hours
To determine the half life of the material; we create a simple decay table that matches the decay time and count rates.
time (years) count rate
0 2000 decays/minute
2 1000 decays/minute
4 500 decays/minute
Half life is the time intervals = 2 years
Also using a formula;
[tex]N = \frac{N_o}{(t/2)^2} \\\\N_o-is \ the \ initial \ count\ rate\\\\N-is \ the \ final \ count\ rate\\\\t/_2 - is \ the\ half\ life \\\\N = \frac{N_o}{(t/2)^2} \\\\500 = \frac{2000}{(t/2)^2}\\\\(t/_2)^2 = \frac{2000}{500} \\\\(t/_2)^2 = 4\\\\t/_2 = \sqrt{4} \\\\t/_2 = 2 \ years[/tex]
Therefore, the half-life of the material is 2 years