Answer:
The empirical formula of dimethylmercury is C2H6Hg
Explanation:
Dimethylmercury, as it says in the name, presents not only the mercury metal in its structure (Hg) but also two radical groups called methyl, which is why its name begins with the prefix DI, referring to the fact that there are two methyl.
Compare the conjugate bases of these three acids. Acid 1: hypochlorous acid , HClO Acid 2: phosphoric acid , H3PO4 Acid 3: hydrogen sulfide , HS- What is the formula for the weakest conjugate base ?
Answer:
The weakest conjugate is HClO-.
Explanation:
As a general rule, the stronger the Bronsted-Lowry acid, the weaker its conjugate base, and vice versa.
Acid 1: HClO is a strong acid, hence its conjugate base would be weak
Acid 2: H3PO4 is a weak acid, hence its conjugate base would be strong
Acid 3: hydrogen sulphide is also a moderately weak acid with a moderately strong conjugate base.
In order of increasing strengths:
HClO < H2S < H3PO4
A rule of thumb is that a reaction rate roughly doubles for every 10 °C increase in temperature. What is the activation energy of a reaction whose rate exactly doubles between 25.0 °C and 35.0 °C
Answer:
FOR EVERY 10 DEGREE CELSIUS INCREASE IN TEMPERATURE, THE ACTIVATION ENERGY THAT SHOWS THIS IS 52.4 KJ/MOL
Explanation:
From Arrhenius equation, the relationship between the rate constant and the temperature is as shown below:
k = Ae^ -Ea/RT
At initial temperature T1, the initial rate constant is (k1)
At final temperature T2, the final rate constant is k2
For the reaction rate to be doubled, we must double the rate constant which shows that the ratio of k2 / k1 must be equal to 2.
That is, k2 / k1 = 2 (rate is doubled)
Equating this into the Arrhenius equation, we have:
k2 / k1 = Ae^ (-Ea / R ) (1/ T2 - 1/T1)
2 = e^ (-Ea / R) (1 / T2 = 1 / T1)
Taking the natural logarithm of both sides:
ln 2 = - (Ea / R) (1 / T2 - 1 / T1)
Making Ea the subject of the formula, we obtain:
Ea = - (ln 2 R / (1 / T2- 1 / T1))
Let T1 = 25 C = 25 + 273 K = 298 K
T2 = 35 C = 35 + 273 K = 308 K
R = 8.314
So,
Ea = - (ln 2 * 8.314 / ( 1/308 - 1 / 298))
Ea = - (0.693 * 8.314 / 0.00324 - 0.00335)
Ea = - 5.7616 / -0.00011
Ea = 52 378,18 J / mol
So therefore, the activation energy Ea is 52.4 kJ/mol.
A solution is made by adding 35.5 mL of concentrated hydrochloric acid ( 37.3 wt% , density 1.19 g/mL1.19 g/mL ) to some water in a volumetric flask, and then adding water to the mark to make exactly 250 mL 250 mL of solution. Calculate the concentration of this solution in molarity.
Answer:
1.73 M
Explanation:
We must first obtain the concentration of the concentrated acid from the formula;
Co= 10pd/M
Where
Co= concentration of concentrated acid = (the unknown)
p= percentage concentration of concentrated acid= 37.3%
d= density of concentrated acid = 1.19 g/ml
M= Molar mass of the anhydrous acid
Molar mass of anhydrous HCl= 1 +35.5= 36.5 gmol-1
Substituting values;
Co= 10 × 37.3 × 1.19/36.5
Co= 443.87/36.6
Co= 12.16 M
We can now use the dilution formula
CoVo= CdVd
Where;
Co= concentration of concentrated acid= 12.16 M
Vo= volume of concentrated acid = 35.5 ml
Cd= concentration of dilute acid =(the unknown)
Vd= volume of dilute acid = 250ml
Substituting values and making Cd the subject of the formula;
Cd= CoVo/Vd
Cd= 12.16 × 35.5/250
Cd= 1.73 M
What must happen for an ionic bond to be created between two elements?
Answer:
they must be heated
Explanation:
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.
Smooth muscle myosin is a motor protein that plays a crucial role in the contraction of smooth muscle. If this protein has a molar mass of 480,000 grams/mol, what is the mass, in grams, of 27 moles of smooth muscle myosin
Answer: Thus the mass, in grams, of 27 moles of smooth muscle myosin is 12960000 grams
Explanation:
According to avogadro's law, 1 mole of every substance weighs equal to the molecular mass, occupies 22.4 L at STP contains avogadro's number [tex](6.023\times 10^{23})[/tex] of particles.
Molecular mass of protein = 480,000 g/mol
Thus 1 mole of protein weighs = 480,000 g
So 27 moles of protein weighs = [tex]\frac{480,000}{1}\times 27=12960000g[/tex]
Thus the mass, in grams, of 27 moles of smooth muscle myosin is 12960000 grams
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)
Consider the following reaction where Kc = 1.29×10-2 at 600 K: COCl2 (g) CO (g) + Cl2 (g) A reaction mixture was found to contain 0.104 moles of COCl2 (g), 4.66×10-2 moles of CO (g), and 3.76×10-2 moles of Cl2 (g), in a 1.00 liter container. Indicate True (T) or False (F) for each of the following:
1. In order to reach equilibrium COCl2(g) must be consumed.
A. True B. False
2. In order to reach equilibrium Kc must increase.
A. True B. False
3. In order to reach equilibrium CO must be consumed.
A. True B. False
4. Qc is greater than Kc.
A. True B. False
5. The reaction is at equilibrium. No further reaction will occur.
A. True B. False
Answer:
1. In order to reach equilibrium COCl₂(g) must be consumed.
B. False
2. In order to reach equilibrium Kc must increase.
B. False .
3. In order to reach equilibrium CO must be consumed.
A. True.
4. Qc is greater than Kc.
A. True
5. The reaction is at equilibrium. No further reaction will occur.
B. False.
Explanation:
Based on the reaction:
COCl₂(g) → CO (g) + Cl₂(g)
And Kc is defined as:
Kc = 1.29x10⁻² = [CO] [Cl₂] / [COCl₂]
Molar concentrations of each species are:
[COCl₂] = 0.104 moles of COCl₂ / 1L = 0.104M
[CO] = 4.66×10⁻² moles of CO / 1L = 4.66×10⁻²M
[Cl₂] = 3.76×10⁻² moles of Cl₂ / 1L = 3.76×10⁻²M
Replacing in Kc formula:
4.66×10⁻²M × 3.76×10⁻²M / 0.104M = 1.68x10⁻²
As the concentrations are not in equilibrium, 1.68x10⁻² is defined as the reaction quotient, Qc.
As Qc > Kc, the reaction will shift to the left producing more COCl₂ and consuming CO and Cl₂. Thus
1. In order to reach equilibrium COCl₂(g) must be consumed.
B. False
2. In order to reach equilibrium Kc must increase.
B. False . Kc is a constant that never change.
3. In order to reach equilibrium CO must be consumed.
A. True.
4. Qc is greater than Kc.
A. True
5. The reaction is at equilibrium. No further reaction will occur.
B. False. The reaction is in equilibrium when Qc = Kc
How many moles would 1.204x1024 atoms of oxygen be? (Remember Avogadro's number is 6.022x1023
Answer:
7.25 x 10^47
Explanation:
1.204 x 10^24 moles*6.022 x 10^23 avogadro's number= 7.25 x 10^47
The molar enthalpy of
mole of a liquid.
is the heat required to vaporize one
thermochemical equation
combustion
released
vaporization
fusion
absorbed
heat
Answer:
vaporization
Explanation:
The molar enthapy of _vaporization______ is the heat required to vaporize one mole of a liquid”
30
Drag each number to the correct location on the equation. Each number can be used more than once, but not all numbers will be used.
Balance the equation with the correct coefficients.
2
3
4
5
SIO2 +
HF → SiF4 +
H2O
Reset
Next
Answer:
The balanced equation is given below:
SiO2 + 4HF —> SiF4 + 2H2O
The coefficients are 1, 4, 1, 2
Explanation:
The equation for the reaction is given below:
SiO2 + HF —> SiF4 + H2O
The above equation can be balance by as follow:
There are 4 atoms of F on the right side and 1 atom on the left side. It can be balance by putting 4 in front of HF as shown below:
SiO2 + 4HF —> SiF4 + H2O
Therefore are 4 atoms of H on the left side and 2 atoms on the right side. It can be balance by putting 2 in front of H2O as shown below:
SiO2 + 4HF —> SiF4 + 2H2O
Now the equation is balanced.
CHEMISTRY HELP!
using only the periodic table, determine the charge on the ion that is formed by arsenic.
The ion charge is:
a. -3
b. -2
c. -1
d. 0
e. +1
f. +2
g. +3
also what is it for elements lithium and strontium?
Answer:
A
Explanation:
Arsenic is in the same group as Nitrogen - group 5. They all have 5 valence electrons in their outermost shell. To achieve its most stable state - 8 valence electrons (octet rule - elements are most stable when the entire shell is filled) - arsenic needs to gain 3 electrons. Since electrons have a negative charge, the charge of an As ion would be -3.
Try observing the periodic table and how many valence electrons that each element has. From there, you can determine the charges of the elements lithium and strontium. You can guess, I'll help you with those once you attempt to find the charge of those ions.
A student takes a measured volume of 3.00 M HCl to prepare a 50.0 mL sample of 1.80 M HCI. What volume of 3.00 M HCI
did the student use to make the sample?
Use M,V;-MV
3.70 mL
16.7 ml
30.0 mL
83.3 mL
Mark this and return
Save and Exit
Next
Submit
Answer:
30 mL VOLUME OF 3.0 M HCl SHOULD BE USED BY THE STUDENT TO MAKE A 1.80 M IN 50 mL OF HCl.
Explanation:
M1 = 3.00 M
M2 = 1.80 M
V2 = 50 .0 mL = 50 /1000 L = 0.05 L
V1 = unknown
In solving this question, we know that number of moles of a solution is equal to the molar concentration multiplied by the volume. To compare two samples, we equate both number of moles and substitute for the required component.
So we use the equation:
M1 V1 = M2 V2
V1 = M2 V2 / M1
V2 = 1.80 * 0.05 / 3.0
V2 = 0.09 /3.0
V2 = 0.03 L or 30 mL
To prepare the sample of 1.80 M HCl in 50.0 mL from a 3.0 M HCl, 30 mL volume should be used.
Answer:
C on edg 2021Explanation:
i dont like reading
Fishing trawlers in a certain bay catch a large variety of marketable fish along with a species of eel that is toxic. They normally kill the eels and throw them back into the sea. What term is used to refer to the eel? The eel species is called a(n) ______ of the fishing operation.
Answer:
1. Non-target
2. Bycatch
Explanation:
In the fishing industry, the main aim of the industry is to capture fishes that can be used or eaten and sell. A variety of fishes are captured for this purpose and since they are used therefore are known as Target catch.
But there are some species which has to be discarded because they are toxic and not useful. These non-useful species like eel which gets captured in the net while capturing other fishes are known as Non-target fish.
The eel fish which gets captured is known as bycatch fishes in the fishing operation.
Thus, Non-target and Bycatch are the correct answer.
Answer:
Its just bycatch
Explanation:
The eel species is called a(n) bycatch of the fishing operation.
Give the full electron configuration for sulfur.
electron configuration:
Answer:
[Ne] 3s² 3p⁴
Electrons per shell: 2,8,6
Answer : 2,8,6 (Sulphur Atom)
2,8,8 (Sulphur Ion)
Give the IUPAC name for the following compound
Answer:
3–bromo–5–chloro–4–methylhexane.
Explanation:
To name the compound given in the question, the following must be observed:
1. Locate the longest continuous carbon chain. This gives the parent name of the compound. In this case, the longest chain is carbon 6 i.e Hexane.
2. Identify the substituents attached. In this case the substituents attached are:
a. Chloro i.e Cl.
b. Bromo ie Br.
c. Methyl i.e CH3.
3. Give the substituents the lowest possible count alphabetically. Bromo comes before Chloro alphabetically, so we shall consider bromo first. Their positions are given below:
Bromo i.e Br at carbon 3
Chloro i.e Cl is at carbon 5
Methyl i.e CH3 is at carbon 4
4. Combine the above to get the name of the compound.
Therefore, the name of the compound is:
3–bromo–5–chloro–4–methylhexane.
What is in period 6 group 8
Answer:
Osmium
Explanation:
If you take a look at the attached image of a periodic table below, you will see that the element in the 6th period and 8th group is Osmium. Hope this helps!
differentiate between sol,aerosol and solid soluti
Answer:
Sol is a colloidal suspension with solid particles in a liquid. Foam is formed when many gas particles are trapped in a liquid or solid. Aerosol contains small particles of liquid or solid dispersed in a gas. While solid solution contain solid as solute in either solid, liquid or gas.
what is the color of benzene and bromine
Explanation:
Benzene is colorless, with a sweet odour.
Color of Bromine is reddish brown .
Hope this helps.
When 106 g of water at a temperature of 21.4 °C is mixed with 64.3 g of water at an unknown temperature, the final temperature of the resulting mixture is 46.8 °C. What was the initial temperature of the second sample of water? (The specific heat capacity of liquid water is 4.184 J/g ⋅ K.)
Answer:
THE INITIAL TEMPERATURE OF THE SECOND SAMPLE IS 4.93 C OR 277.93 K
Explanation:
Mass of first sample of water = 106 g
Initial temp of first sample = 21.4 °C = 21.4 + 273 K = 294.4 K
Mass of second sample = 64.3 g
Final temp of theresulting mixture = 46.8 °C = 46.8 + 273 K = 319.8 K
Specific heat capacity of water = 4.184 J/g K
It is worthy to note that;
Heat gained by the first sample = Heat lost by the second sample
Since heat = mass * specific heat capacity * change in temperature, we have
Mass * specific heat * change in temp of the first sample = Mass * specific heat * change in temp. of the second sample
MC (T2 - T1) = MC (T2-T1)
106 * 4.184 * ( 319.8 - 294.4) = 64.3 * 4.184 * ( 319.8 - T1)
106 * 4.184 * 25.4 = 269.0312 ( 319.8 - T1)
11 265.0016 = 269.0312 (319.8 - T1)
Since the change in temperature = 319.8 -T1
Change in temperature =11265.0016 / 269.0312
Change in temperature = 41.87
Change in temperature = 319.8 -T1
41.87 = 319.8 - T1
T1 = 319.8 - 41.87
T1 = 277.93 K
T1 = 4.93 °C
So therefore, the initial temperature of the sacond sample is 4.73 °C or 277.93 K
A chemist titrates of a butanoic acid solution with solution at . Calculate the pH at equivalence. The of butanoic acid is__________ .Round your answer to decimal places.
Note for advanced students: you may assume the total volume of the solution equals the initial volume plus the volume of solution added.
Answer:
pH = 8.75
Explanation:
100.0mL of a 0.8108M of a butanoic acid (HC₃H₇CO₂, pKa 4.82) solution is titrated with 0.0520M KOH.
The reaction is:
HC₃H₇CO₂ + KOH → H₂O + KC₃H₇CO
Moles of butanoic acid are:
0.1000L × (0.8108mol / L) = 0.08108 moles of butanoic
For a complete reaction, volume of KOH must be added is the volume in which 0.08108 moles of KOH are added, that is:
0.08108 mol × (L / 0.0520mol) = 1.56L of KOH.
Total volume in equilibrium is 1.56L + 0.10L = 1.66L
That means concentration of butanoic acid is:
0.08108 mol / 1.66L = 0.04884M HC₃H₇CO₂
At equivalence point, there is just C₃H₇CO⁻ in solution
Kb of butanoic acid is:
C₃H₇CO⁻ + H₂O ⇄ HC₃H₇CO₂ + OH⁻
Kb = Kw / Ka
Ka = 10^-pKa
Ka = 1.51x10⁻⁵
Kb = 1x10⁻¹⁴ / 1.51x10⁻⁵ = 6.61x10⁻¹⁰
The equilibrium of Kb is:
Kb = 6.61x10⁻¹⁰ = [HC₃H₇CO₂] [OH⁻] / [C₃H₇CO⁻]
As at equivalence point there is just C₃H₇CO⁻, the equilibrium concentrations are:
[C₃H₇CO⁻] = 0.04884M - X
[HC₃H₇CO₂] = X
[OH⁻] = X
Replacing in Kb:
6.61x10⁻¹⁰ = X² / [0.04884M - X]
0 = X² + 6.61x10⁻¹⁰X - 3.23x10⁻¹¹
Solving for X:
X = -5.68x10⁻⁶ → False solution. There is no negative concentrations
X = 5.683x10⁻⁶ → Right solution.
As [OH⁻] = X, [OH⁻] = 5.683x10⁻⁶.
pOH = - log [OH⁻]
pOH = 5.245
pH = 14 - pOH
pH = 8.75Classify the following unbalanced chemical reaction Fe(OH)2(s) + HCl(aq) = FeCl2(aq) + H2O(l)
1. Acid-Base Reaction
2. Precipitation Reaction
3. Oxidation-Reduction Reaction
4. Combustion Reaction
Answer:
1. Acid-Base Reaction
Explanation:
Fe(OH)2(s) + HCl(aq) = FeCl2(aq) + H2O(l)
base acid
This a reaction between base and acid.
Ferrous hydroxide is an inorganic alkaline compound whereas hydrochloric acid is an acid. The reaction between Fe(OH)₂and HCl is an acid-base reaction. Thus, option 1 is correct.
What is an acid-base reaction?An acid-base reaction is a chemical change that occurs and takes place when the reactant constitutes an acid and a base. They are characterized by the exchange of protons that results in the formation of conjugate bases and acids or salt.
The acid-base chemical reaction is shown as,
Fe(OH)₂(s) + HCl(aq) ⇒ FeCl₂(aq) + H₂O(l)
Here, ferrous hydroxide is a base with hydroxide ions and hydrochloric acid is an acid with hydrogen ions. HCl donates its proton to form water molecules with hydroxide ions of ferrous hydroxide.
Therefore, in option 1. the reaction is an acid-base reaction.
Learn more about acid-base reaction, here:
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which element causes burning when me mix it with oxygen
Answer:
Hydrogen peroxide is ans
4-Methylphenol, CH3C6H4OH (pKa 10.26), is only slightly soluble in water, but its sodium salt, CH3C6H4O-Na , is quite soluble in water. Describe the solubility of 4-methylphenol in solutions of sodium hydroxide, sodium bicarbonate (NaHCO3), and sodium carbonate (Na2CO3). The pKa values for the conjugate acids of sodium hydroxide, sodium bicarbonate (NaHCO3), and sodium carbonate (Na2CO3) are 15.7, 6.36, and 10.33, respectively.
Explanation:
We know that more is the [tex]pK_{a}[/tex] value, weaker will be the acid. Also, an acid completely dissociates into ions in an aqueous base solution when [tex]pK_{a}[/tex] of conjugate acid of base is greater than acid.
4-methylphenol [tex](CH_{3}C_{6}H_{4}OH)[/tex] ([tex]pK_{a} = 10.26[/tex]) is quite soluble in its sodium salt. In NaOH, the dissociation will be as [tex]Na^{+}[/tex] and [tex]OH^{-}[/tex] ions as NaOH is a strong base.
Therefore, 4-methylphenol will readily dissolve in NaOH solution.
As, [tex]NaHCO_{3}[/tex] is not a strong base but as 4-Methylphenol forms a sodium salt hence, it will have a low solubility as compared to NaOH.
Whereas [tex]Na_{2}CO_{3}[/tex] is not a base but when dissolved in water it shows basic character as it produces NaOH (strong base) and [tex]H_{2}CO_{3}[/tex] (weak acid). As a result, the solution gets basic. Hence, 4-methylphenol will readily dissolve in [tex]Na_{2}CO_{3}[/tex].
3. Scientific methods may include three steps of study as listed below. Explain each step in detail with a complete content related sentence. (ref: p.12-16) a. Hypothesis b. Theory c. Scientific law
Answer:
Hypothesis is an assumption or idea about a particular topic or argument. An hypothesis should be one which is able to be tested and measurable to determine its authenticity.
A theory is an explanation of a scientific observation which has undergone series of experiments and is reproducible in any part of the world.
A law is simply a rule which gives an in depth explanation of a scientific finding. If new findings emerge the law could be changed or modified.
1. There are how many mol of oxygen in 3.5 mol of caffeine.
Answer:
7 mol
Explanation:
Caffeine molecular formula C8H10N4O2. It has 2 atoms of oxygen.
C8H10N4O2 - 2O
1 mol 2 mol
3.5 mol x mol
x = 3.5*2/1 = 7 mol
Which process absorbs the greatest amount of heat?
a. the cooling of 10 g of liquid water from 100°C to 0°C.
b. the heating of 10 g of liquid water from 0°C to 100°C.
c. the freezing of 10 g of liquid water the melting of 10 g of ice.
d. the condensation of 10 g of gaseous water.
Answer:
b. the heating of 10 g of liquid water from 0°C to 100°C.
Explanation:
Hello,
In this case, we must notice a., c. and d. processes are not actually absorbing heat but releasing it since cooling, freezing and condensation are processes with negative heat sign since matter changes from a state of more energy to a state of less energy. We can prove this by realizing that freezing enthalpy of water is -6.00 kJ/mol, condensation enthalpy of eater is -40.8 kJ/mol and a change of temperature from 100 °C to 0 °C is negative.
In such a way, the only process absorbing heat is b. the heating of 10 g of liquid water from 0°C to 100°C since energy must be added to the system, or absorbed by it in order to attain the heating.
Regards.
The process having the greatest amount of heat is:
b. the heating of 10 g of liquid water from 0°C to 100°C.
Looking at all the options:The options a., c. and d. processes are not actually absorbing heat but releasing it since cooling, freezing and condensation are processes with negative heat sign since matter changes from a state of more energy to a state of less energy.
The freezing enthalpy of water is -6.00 kJ/mol, condensation enthalpy of eater is -40.8 kJ/mol and a change of temperature from 100 °C to 0 °C is negative.
So out of all the options, only process at b is a heating process thus it will absorb greatest amount of heat.
Find more information about Heat here:
brainly.com/question/13439286
If a pork roast must absorb 1500 kJkJ to fully cook, and if only 14% of the heat produced by the barbeque is actually absorbed by the roast, what mass of CO2CO2 is emitted into the atmosphere during the grilling of the pork roast?
You need to know the amount of heat generated by the combustion reaction.
Assuming propane as fuel, you can use thiis data:
C3H8(g)+5O2(g)---3CO2(g)+4H2O(g) ΔH= -2217 KJ
So when 3 moles of CO2 is emmitted 2217 kJ of heat is produced.
The molar wegiht of CO2 is 12 g/mol + 2 * 16 g/mol = 44 g/mol.
Then 3 mol * 44 g / mol = 132 g of CO2 are produced with 2217 kJ of heat.
Now you have to calculate how much energy you need to produce if only 12% is abosrbed by the pork
Energy absorbed by the pork = 12% * total energy =>
total energy = energy absorbed by the pork / 0.12 = 1700 kJ / 0.12 = 14,166.67 kJ.
Now, state the proportion:
132 g CO2 / 2217 kJ = x / 14,166.7 kJ =>
x = 14,166.67 * 132 / 2217 = 843.48 g CO2.
Answer: 843 g of CO2
Light travels three-fourths as fast through water as it does through a vacuum.
What is water's index of refraction?
The half-life of radium-226 is 1590 years. (a) A sample of radium-226 has a mass of 50 mg. Find a formula for the mass of the sample that remains after t years. (b) Find the mass after 500 years correct to the nearest milligram. (c) When will the mass be reduced to 40 mg
Answer:
Explanation:
a )
m = m₀ [tex]e^{-\lambda t[/tex]
m is mass after time t . original mass is m₀ , λ is disintegration constant
λ = .693 / half life
= .693 / 1590
= .0004358
m = m₀ [tex]e^{- 0.0004358 t}[/tex]
b )
m = 50 x [tex]e^{-.0004358\times 500}[/tex]
= 40.21 mg .
c )
40 = 50 [tex]e^{-.0004358t[/tex]
.8 = [tex]e^{-.0004358t[/tex]
[tex]e^{.0004358t[/tex] = 1.25
.0004358 t = .22314
t = 512 years .
