Answer:
The current mass fraction of [tex]^{14}_{6} C[/tex] should be approximately 68.8 percent.
Explanation:
[tex]^{14}_{6} C[/tex] is a radioactive isotope with a halflife of 5568 years. The decay of any radioisotope is modelled after the following ordinary differential equation:
[tex]\frac{dm}{dt} = -\frac{m}{\tau}[/tex]
Where:
[tex]m[/tex] - Current mass of the isotope, measured in grams.
[tex]\tau[/tex] - Time constant, measured in years.
The solution of this equation is of the form:
[tex]m(t) = m_{o}\cdot e^{-\frac{t}{\tau} }[/tex]
Where:
[tex]t[/tex] - Time, measured in years.
[tex]m_{o}[/tex] - Initial mass of the isotope, measured in grams.
The time constant can be found as a function of halflife ([tex]t_{1/2}[/tex]):
[tex]\tau = \frac{t_{1/2}}{\ln 2}[/tex]
If [tex]t_{1/2} = 5568\,yrs[/tex] and [tex]t = 3000\,yrs[/tex], the mass fraction of [tex]^{14}_{6} C[/tex] is:
[tex]\tau = \frac{5568\,yrs}{\ln 2}[/tex]
[tex]\tau \approx 8032.926\,yrs[/tex]
[tex]\frac{m(3000\,yrs)}{m_{o}} = e^{-\frac{3000\,yrs}{8032.926\,yrs} }[/tex]
[tex]\frac{m(3000\,yrs)}{m_{o}} \approx 0.688[/tex]
The current mass fraction of [tex]^{14}_{6} C[/tex] should be approximately 68.8 percent.
Which is not true about the liquid state of matter?
The liquid state has a definite volume and a definite shape.
The liquid state takes on the shape of its container.
The liquid state has a definite volume and an indefinite shape.
The particles in a liquid can easily move past each other.
Answer:
The liquid state has a definite volume and a definite shape.
Date
Pages
Equivalent weight of the compound
caco3
Answer:
CaCO3,which is Calcium Carbonate. It’s equivalent mass is 50 g. Explanation:-. Mass of CaCO3=Mass of 1 atom of Calcium (Ca)+Mass of 1 atom of Carbon (C)+Mass of 3 atoms of Oxygen (O). Mass of 1 atom of Calcium=1×40g=40g. Mass of 1 atom of Carbon=1×12g=12g. Mass of 3 atoms of Oxygen=3×16g=48g.
Explanation: Hope this helps :)
A 100-watt light bulb radiates energy at a rate of 100 J/s. (The watt, a unit of power or energy over time, is defined as 1 J/s J/s.) If all of the light emitted has a wavelength of 525nm 525nm, how many photons are emitted per second? Express your answer to three significant figures.
Answer:
Approximately [tex]2.64\times 10^{20}[/tex] (assumption: wavelength [tex]525\; \rm nm[/tex] is measured in vacuum, where the speed of light is approximately [tex]3.0\times 10^{8}\; \rm m \cdot s^{-1}[/tex].)
Explanation:
Convert the unit of wavelength to meters:
[tex]\displaystyle \lambda = 525\; \rm nm = 525 \; \rm nm\times \frac{10^{-9}\; \rm m}{1\; \rm nm} = 5.25 \times 10^{-7}\; \rm m[/tex].
Assume that the wavelength [tex]525\; \rm nm[/tex] is measured in vacuum, where the speed of light is approximately [tex]2.99792\times 10^{8}\; \rm m \cdot s^{-1}[/tex]. Calculate the frequency of this light from its wavelength:
[tex]\displaystyle f = \frac{c}{\lambda} \approx \frac{2.99792\times 10^{8}\; \rm m \cdot s^{-1}}{5.25 \times 10^{-7}\; \rm m} \approx 5.71429\times 10^{14}\; \rm s^{-1}[/tex].
The Planck's Constant can help find the energy of a photon given its frequency. Look up this constant to more than three significant figures:
[tex]h \approx 6.62607\times 10^{-34}\; \rm J \cdot s^{-1}[/tex].
Calculate the energy of one such photon:
[tex]\begin{aligned} E &= h \cdot f\\ &\approx 6.62607\times 10^{-34}\; \rm J \cdot s^{-1} \times 5.71023\times 10^{14}\; \rm s \\ &\approx 3.78370\times 10^{-19}\; \rm J \end{aligned}[/tex].
Calculate the number of these photons that [tex]100\; \rm J[/tex] of energy can produce under the assumption of [tex]100\%[/tex] conversion:
[tex]\displaystyle \frac{100\; \rm J}{3.78370\times 10^{-19}\; \rm J} \approx 2.64\times 10^{20}[/tex].
(Rounded to three significant figures.)
Buck's Turf Care Company mowed 229 lawns over a 18 week period. What is the average weekly rate of mowing lawns?
Answer:
Average weekly rate of mowing lawns = 13 lawns (Approx)
Explanation:
Given:
Total lawns mowed = 229
Total number of period = 18 week
Find:
Average weekly rate of mowing lawns
Computation:
Average weekly rate of mowing lawns = Total lawns mowed / Total number of period
Average weekly rate of mowing lawns = 229 / 18
Average weekly rate of mowing lawns = 12.72
Average weekly rate of mowing lawns = 13 lawns (Approx)
A sprinter is running 200.0 m in 21.9s. What is the average speed of the sprinter in km per hour?
Answer:
Average speed = 333.3 km/hrExplanation:
The average speed of a body can be found by using the formula
[tex]Average \: \: speed = \frac{distance}{time} [/tex]
To find the average speed in km/h first convert the distance from m to km and the seconds from s to hr.
For the distance
2000 m
1000 m = 1 km
2000 m = 2000/1000 = 2 km
For the seconds
21.9 s
3600 s = 1 hr
21.9 s = 21.9/3600 = 0.006 hrs
Substitute the values into the above formula and solve for the Average speed
That's
[tex]Average \: \: speed = \frac{2}{0.006} [/tex]
We have the final answer as
Average speed = 333.3 km/hr
Hope this helps you
How many grams of chlorine gas are present in a 150. liter cylinder of chlorine held at a pressure of 1.00 atm and 0. °C? Group of answer choices
Answer:
474 grams of chlorine gas are present in a 150 liter cylinder of chlorine held at a pressure of 1.00 atm and 0 °C
Explanation:
An ideal gas is a theoretical gas that is considered to be composed of randomly moving point particles that do not interact with each other. Gases in general are ideal when they are at high temperatures and low pressures.
The pressure, P, the temperature, T, and the volume, V, of an ideal gas, are related by a simple formula called the ideal gas law:
P*V = n*R*T
where P is the gas pressure, V is the volume that occupies, T is its temperature, R is the ideal gas constant, and n is the number of moles of the gas.
In this case:
P= 1.00 atmV= 150 Ln= ?R= 0.082 [tex]\frac{atm*L}{mol*K}[/tex]T= 0 C= 273 KReplacing:
1.00 atm* 150 L= n*0.08206 [tex]\frac{atm*L}{mol*K}[/tex] *273 K
Solving:
[tex]n=\frac{1.00 atm* 150 L}{0.08206 \frac{atm*L}{mol*K}*273 K}[/tex]
n= 6.69 moles
Being Cl= 35.45 g/mole, the molar mass of chlorine gas is:
Cl₂=2*35.45 g/mole= 70.9 g/mole
So if 1 mole has 70.9 grams, 6.69 moles of the gas, how much mass does it have?
[tex]mass=\frac{6.69 moles*70.9 grams}{1 mole}[/tex]
mass= 474.321 grams ≅ 474 grams
474 grams of chlorine gas are present in a 150 liter cylinder of chlorine held at a pressure of 1.00 atm and 0 °C
The mole is derived from the quantity of atoms in 12 grams of carbon-12. The mole is just a number, it can be used for:_________
Answer:
Explanation:
A mole is the amount of substance that contains as many elementary entities as there are carbon atoms in 12 grams of carbon -12 isotopes i.e. it is the amount of a substance that posses the same number of particles as the number of atoms in exactly 12g of carbon is 12.
The number of atoms in a mole is known to be the Avogadro Number which is equal to 6.02 × 10²³. Thus, a mole of any substance is that amount of the substance which contains 6.02 × 10²³ particles of that substance. The definition of the mole is also given by the relationship:
[tex]\mathtt {moles = \dfrac{ mass \ in \ grams}{ relative \ molecular \ mass}}[/tex]
A sample of motor oil has a mass of 440 g and a volume of 0.27 L. What is its
density (in g/mL)?
Answer:
Density =1.63 g/mLExplanation:
The density of a substance can be found by using the formula
[tex]Density = \frac{mass}{volume} [/tex]
To find the density in g/mL , we must first convert the volume from L to mL
From the question
mass = 440 g
1 L = 1000 mL
0.27 L = 0.27 × 1000 = 270 mL
volume = 270 mL
Substitute the values into the above formula and solve for the Density
That's
[tex]Density = \frac{440}{270} [/tex]
= 1.629629...
We have the final answer as
Density =1.63 g/mLHope this helps you
A children’s pain relief elixir contains 10.6 cg acetaminophen per 1 teaspoon. The dosage recommended for a child who weighs 34 lbs, is 1.5 teaspoons. What is the dosage of acetaminophen, expressed as mg acetaminophen/kg body weight, for a child weighing 34 lbs?(1 kg=2.205 lbs)
Answer:
Dosage of acetaminophen = 15.9 cg acetaminophen
Explanation:
Given:
1 teaspoon = 10.6 cg acetaminophen
Dosage to 34 lbs child = 34 lbs
Given dose = 1.5 teaspoon
Find:
Dosage of acetaminophen
Computation:
⇒ Dosage of acetaminophen = 1.5 teaspoon × [10.6 cg acetaminophen]
Dosage of acetaminophen = 15.9 cg acetaminophen
Is this basalt homogeneous or heterogeneous?
Answer:
heterogeneous
Explanation:
You are given a mixture consisting of marbles, iron filings, sugar and sand. Suggest a series of steps for separating this mixture. You may make a flowchart, but be careful to fully explain each step (Why are you using that method?). When you are finished, you should have each component of the mixture in a separate beaker.
Answer:
Explanation:
Start by sifting the marbles out bc they are bigger they will sit in a big sifter
Than with a magnet roll it in what’s left this will pick up all the iron pieces
Than Fill with water and stir this should resolve the sugar which after you sift out the sand you can heat and scrape off beaker and than for a very short time heat up the sand to dry it and not have extra weight from the water
!!!sand only for a few seconds or else it will fly everywhere and if it gets in eye it will sting badly
what does control mean in scientific method
Answer:
A scientific control is an experiment or observation designed to minimize the effects of variables other than the independent variable. This increases the reliability of the results, often through a comparison between control measurements and the other measurements.A scientific control is an experiment or observation designed to minimize the effects of variables other than the independent variable. This increases the reliability of the results, often through a comparison between control measurements and the other measurements.
Explanation:
Let's all give it up for GOOGLE! where you can literally get an answer to something.
Place these hydrocarbons in order of decreasing boiling point. Rank from highest to lowest boiling point. 1. Paraffin, C40Hg2 2. Propane, G2H53. Hexane, C6H14 4. 2,2-dimethylbutane, C6 H14 5. Heptadecane, C17H36A. Highest BPB. Highest BP
Answer:
Paraffin > Heptadecane > Hexane > 2,2-dimethylbutane > Propane
Explanation:
It must first be establish that all the molecules listed in the question are alkanes. For alkanes, the intermolecular forces between the molecules of alkanes increases with increasing molecular weight. This is as a result of increase in the surface area of the molecule. Increase in surface area implies a greater degree of dispersion forces.
This is the reason why high boiling points are observed for high molecular weight alkanes.
Lead has a density of 11.34 g/mL, if you weigh an empty beaker and it weighs 245.61 grams, then add lead until the scale reads 350.52 grams, what is the volume of lead that you have? *
Answer:
Explanation:
wt. of the lead = wt. of ( flask + lead) - wt.of the empty flask
350.52- 245.61= 104.91 grams of lead
density = mass/volume
11.43= 104.91/V
V = 9.178 ml
What’s the correct IUPAC name for the compound shown here?
Answer : The correct IUPAC name for the compound is, 2,2,4,5-tetramethyl-3-ethylhexane.
Explanation :
The basic rules for naming of hydrocarbons are :
First select the longest possible carbon chain.
The longest possible carbon chain should include the carbons of double or triple bonds.
The naming of alkane is done by adding the suffix -ane, alkene by adding the suffix -ene, alkyne by adding the suffix -yne.
If two or more similar alkyl groups are present in a compound, the prefixes di-, tri-, tetra- and so on are used to specify the number of times of the alkyl groups in the chain.
In the give compound, the longest possible carbon chain has 6 carbon atoms. So, the prefix used will be 'hex-' and also the carbon has single bond between them, so it is an alkane. Four methyl group is present at 2,2,4,5 position of carbon chain and one ethyl group is present at 3 position.
Hence, the correct IUPAC name for the compound is, 2,2,4,5-tetramethyl-3-ethylhexane.
Tetramethyl-2,2,4,5-ethylhexane is the proper IUPAC name for the substance.
Basic guidelines for hydrocarbon naming are as follows:
Choose the longest carbon chain you can.
The carbons of double or triple bonds should be included in the longest carbon chain possible.
The suffixes -ane, -ene, and -yne are used in the naming of alkane, alkene, and alkyne, respectively.
If a compound has two or more identical alkyl groups, the prefixes di-, tri-, tetra-, and so on are used to indicate how many times the alkyl groups are present in the chain.
The longest feasible carbon chain in the given chemical contains 6 carbon atoms. Since there is only one bond between the carbon atoms, the prefix will be "hex-," and an alkane is what is being described. On the carbon chain, there are four methyl groups at positions 2, 2, 4, and 5, and one ethyl group at position 3. Consequently, 2,2,4,5-tetramethyl-3-ethylhexane is the right IUPAC designation for the substance.
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What should scientists do after completing a scientific investigation?
o write a hypothesis
confirm the results
O design the procedure
make observations
D. Make observations
The first thing you do is write a hypothesis then you were designed your procedure, after you make the procedure you would do the procedure, after you do the procedure you would confirm the results, then at the end you would make observations to see that everything is correct.
help pls with chemistry question
Answer:
1×10⁸ Hz.
Explanation:
From the question given above, the following data were obtained:
Wavelength (λ) = 3 m
Frequency (f) =?
The wavelength of a wave and it's frequency are related by the following equation:
Velocity (v) = wavelength (λ) × frequency (f)
v = λf
With the above equation, we can obtain the frequency of the light wave as follow:
Wavelength (λ) = 3 m
Velocity (v) of light = 3×10⁸ m/s
Frequency (f) =?
v = λf
3×10⁸ = 3 × f
Divide both side by 3
f = 3×10⁸ / 3
f = 1×10⁸ Hz
Therefore, the frequency of the light wave is 1×10⁸ Hz
Calculate the degree of unsaturation (or IHD, Index of Hydrogen Deficiency) for C8H12.
Answer:
4.
Explanation:
Hello,
In this case, for the calculation of the degree of unsaturation, we apply the following formula:
[tex]Degree\ of \ insaturation=C-\frac{H}{2}[/tex]
Thus, since we have eight carbon atoms and twelve hydrogen atoms, it turns out:
[tex]Degree\ of \ insaturation=8-\frac{12}{2}=8-6=4[/tex]
It means that four substituents are missing in order saturate the molecule.
Regards.
find how many natural numbers are there between 80 and 120 step by step plz
A saline solution contains 0.800 g of NaCl (molar mass 58.55 g/mol) in 54.6 mL of solution. Calculate the concentration of NaCl in this solution, in units of molarity Express the concentration in molarity to three significant figures.
Answer:
0.25 M
Explanation:
Data obtained from the question include:
Molar mass of NaCl = 58.55 g/mol
Mass of NaCl = 0.800 g
Volume = 54.6 mL
Next, we shall determine the number of mole in 0.800 g of NaCl. This can be obtained as follow:
Molar mass of NaCl = 58.55 g/mol
Mass of NaCl = 0.800 g
Mole of NaCl =?
Mole = mass /Molar mass
Mole of NaCl = 0.8/58.55
Mole of NaCl = 0.0137 mole
Next, we shall convert 54.6 mL to litres (L). This can be obtained as follow:
1000 mL = 1 L
Therefore,
54.6 mL = 54.6 /1000
54.6 mL = 0.0546 L
Finally, we shall determine the molarity of the solution as follow:
Mole of NaCl = 0.0137 mole
Volume = 0.0546 L
Molarity =?
Mol= mole /Volume
Molarity = 0.0137/0.0546
Molarity = 0.25M
Therefore, the molarity of the solution is 0.25 M
What are the laws of Newton?
Answer:
an object that is at rest will stay at rest inless a force acts upon it.
An oject that is in motion will not change its velocity unless a force acts upon it.
Answer:
First law
In an inertial frame of reference, an object either remains at rest or continues to move at a constant velocity, unless acted upon by a force.[2][3]
Second law
In an inertial frame of reference, the vector sum of the forces F on an object is equal to the mass m of that object multiplied by the acceleration a of the object: F = ma. (It is assumed here that the mass m is constant – see below.)
Third law
When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction on the first body.
Indicate the net charge of lysine at pH 9.5.
Answer:
Explanation:
An amino acid like lysine has both the acidic and basic group . They are amphoteric in nature ie they can react with both acid and base . In acidic or basic medium they carry charge of either positive or negative nature .
Lysine is also an amino acid . It has both acidic and basic group . The pka value of its basic side chain is 10.5 . Hence at pH more than it it is neutral or have no charge but at pH value less than 10.5 , it acquires H⁺ ion and becomes positively charged
Hence at pH value of 9.5 which is less than 10.5 , it will be positively charged . It will have net charge of + 1 .
---- NH₂ + H⁺ = ------ NH₃⁺
Explain why heat is often used in a laboratory experiment. a. To warm up the laboratory, b. To speed up a reaction
Answer:
To speed up a reaction
Explanation:
Heat, as well as catalysts, increase the reaction rate of some chemical reactions since they cause the enzymes or reagents in charge of carrying out the transformation to products to act faster and increase their kinetic energy of reaction.
Lap safety rules crossword
Eric's father asked an engineer to survey the field behind their house. He wanted to plant some apple and pear trees there. According to the survey, the field is 38 meters (m) long and 17 meters (m) wide. What is the perimeter of the field in centimeters?
Answer:
11,000 cm
Explanation:
Step 1: Given data
Width of the field (w): 17 meters
Length of the field (l): 38 meters
Step 2: Calculate the perimeter of the field
The field is a rectangle. We can find its perimeter (P) by adding its sides.
P = 2 × w + 2 × l = 2 × 17 m + 2 × 38 m = 110 m
Step 3: Convert the perimeter to centimeters
We will use the relationship 1 m = 100 cm.
110 m × (100 cm/1 m) = 11,000 cm
Though alchemists were often superstitious, they left a rich legacy for modern chemists. What was their main contribution?
though alchemists were often superstitious, they left a rich legacy of modern chemists. what was their main contribution-
Explanation:
they were the first to preform experiments.
The concentration of Salt Solution is teams
of mass by mass it is 20% and the
mass of the Solution IS 550
Detrmine the mass of Solute Present
in th Solution?
Answer:
11
Explanation:
so that is 20\100× 55 that gives you 11
thanks so please follow me
Which of the following compounds are ionic?
a. KCl
b. C2H4
c. BaCl2
d. SiCl4
e. LiF
Answer:
a. KCl, c. BaCl2 and e. LiF.
Explanation:
Hello,
In this case, we can identify the ionic compounds by verifying the difference in the electronegativity between the bonding compounds when it is 1.7 or more (otherwise it is covalent) as shown below:
a. KCl: 3.0-0.9=2.1 -> Ionic.
b. C2H4: 2.5-2.1=0.4 -> Covalent.
c. BaCl2: 3.0-0.8=2.2 -> Ionic.
d. SiCl4: 3.0-1.8=1.2 -> Covalent.
e. LiF: 4.0-1.0=3.0 -> Ionic.
Therefore, ionic compounds are a. KCl, c. BaCl2 and e. LiF.
Regards.
How many moles and numbers of ions of each type are present in the following aqueous solutions?
(a) 88 mL of 1.75 M magnesium chloride,
(b) 321 mL of a solution containing 0.22 g aluminum sulfate/L,
(c) 1.65 L of a solution containing 8.83×10218.83×1021 formula units of cesium nitrate per liter.
Answer:
a. 0.154 moles = 2.78x10²³ ions
b. 2.18x10⁻⁴ moles = 6.56x10²⁰ ions
c. 1.77x10²² ions = 0.0147 moles
Explanation:
The multiplication of volume of solution in liters times molarity gives the moles of solute.
a. Moles MgCl₂:
88mL = 0.088L * (1.75mol / L) = 0.154 moles MgCl₂
Uaing Avogadro's number:
0.154mol *(6.022x10²³ molecules / 1 mol) = 9.27x10²² molecules.
As 1 molecule of MgCl₂ contains 3 ions:
Ions = 2.78x10²³
b. Moles Al₂(SO₄)₃:
Aluminium sulfate has a molar mass of 324.15g/mol:
0.321L * (0.22g Al₂(SO₄)₃ / L) * (1mol / 324.15g) = 2.18x10⁻⁴ moles.
1 molecule contains 5 ions:
2.18x10⁻⁴ moles *(6.022x10²³ molecules / 1 mol) * 5 = 6.56x10²⁰ ions.
c. 8.83x10²¹ formula units of CsNO₃ = Number of molecules. Ions are:
8.83x10²¹ * 2 = 1.77x10²² ions
And moles are:
8.83x10²¹ Formula units * (1mol / 6.022x10²³) = 0.0147 moles
a. The number of moles and number of ions should be 0.154 moles and 2.78x10²³ ions
b. The number of moles and number of ions should be 2.18x10⁻⁴ moles and 6.56x10²⁰ ions
c. The number of moles and number of ions should be 1.77x10²² ions and 0.0147 moles
Calculation of the no of moles and no of ions:a. Moles MgCl₂:
Here,
88mL = 0.088L * (1.75mol / L) = 0.154 moles MgCl₂
Now here we used Avogadro's number:
So,
0.154mol *(6.022x10²³ molecules / 1 mol) = 9.27x10²² molecules.
Since 1 molecule of MgCl₂ contains 3 ions:
So,
Ions = 2.78x10²³
b. Moles Al₂(SO₄)₃:
Since Aluminum sulfate has a molar mass of 324.15g/mol:
So,
0.321L * (0.22g Al₂(SO₄)₃ / L) * (1mol / 324.15g) = 2.18x10⁻⁴ moles.
Now
1 molecule contains 5 ions:
So,
2.18x10⁻⁴ moles *(6.022x10²³ molecules / 1 mol) * 5 = 6.56x10²⁰ ions.
c. Since
8.83x10²¹ formula units of CsNO₃ = Number of molecules. Ions are:
So,
8.83x10²¹ * 2 = 1.77x10²² ions
And moles are:
8.83x10²¹ Formula units * (1mol / 6.022x10²³) = 0.0147 moles
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A compound contains 16.7 g of iridium and 10.3 g of selenium, what is its empirical formula?
Answer:
THE EMPIRICAL FORMULA OF THE COMPOUND IS Ir Se2
Explanation:
Iridium = 16.7 g
Selenium = 10.3 g
Total mass = 16.7 + 10.3 = 27 g
To calculate the empirical formula, we first calculate the percentage com[position of the individual elements.
Percentage composition of iridium = 16.7 / 27 * 100 = 61.85 %
Percentage composition of selenium = 10.3 / 27 * 100 = 38.15 %
Next is to divide the percentage composition of each element by their respective molecular masses
Molecular mass of iridium = 192 g/mol
Molecular mass of selenium = 79g/mol
Iridium = 61.85 / 192 = 0.3221
Selenium = 38.15 / 79 = 0.4829
Next is to divide the values by the smaller of the two values
Iridium = 0.3221 / 0.3221 = 1
Selenium = 0.4829 / 0.3221 = 1.5
Next is to round up the values to a whole number
Iridium = 1
Selenium = 2
The empirical formula therefore is Ir Se2