Carbon-14 is a radioisotope of carbon that decays following first-order kinetics. There are four values of interest in this problem: the "normal" (or original) amount of carbon-14 for a jawbone ([tex]\mathrm{N_0}[/tex]), the actual amount of carbon-14 in a jawbone ([tex]\mathrm{N}[/tex]), the half-life of carbon-14 ([tex]\mathrm{t_{1/2}}[/tex]), and the actual time elapsed ([tex]\mathrm{t}[/tex]) from the original time. There is an equation that ties all these values in together,
[tex]N= N_0 e^{-kt}[/tex]
where k is the rate constant, which, for first-order decay, is related to the half-life by
[tex]k = \dfrac{\ln 2}{ t_{1/2} }.[/tex]
What you want to find here is the time elapsed (t). So, you can substitute the latter equation for k into the k in the former equation to get
[tex]N= N_0 e^{\frac{-\ln 2 \;t}{t_{1/2}}.[/tex]
Rearranging to solve for t, the equation becomes
[tex]t = \left(\dfrac{\ln \dfrac{N_0}{N}}{\ln 2} \right) t_{1/2}.[/tex]
You are given all three of the values necessary to solve for t: The normal amount of carbon-14 is 200 mg; the actual amount of carbon-14 in the sample is 50 mg; and the half-life of carbon-14 is 5730 years. Plugging them into the above equation, we get
[tex]t = \left(\dfrac{\ln \dfrac{200 \text{ mg}}{50 \text{ mg}}}{\ln 2} \right) \left(5730 \text{ years} \right) = 11460 \text{ years}.[/tex]
So the jawbone found is 11460 years old (or 11000 if accounting for sig figs).
PLEASE HELP!!
15POINTS!!! And brainliest
Answer: a. 3.36 L
b. 33.2 g
Explanation:
According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number [tex]6.023\times 10^{23}[/tex] of particles.
Standard condition of temperature (STP) is 273 K and atmospheric pressure is 1 atm respectively.
To calculate the number of moles, we use the equation:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]
[tex]\text{Number of moles of} Fe_2O_3=\frac{16.0g}{159.69g/mol}=0.1mole[/tex]
[tex]3O_2(g)+4Fe(s)\rightarrow 2Fe_2O_3(s)[/tex]
a. 2 moles of [tex]Fe_2O_3[/tex] are produced by = [tex]3\times 22.4L=67.2L[/tex] of [tex]O_2[/tex]
Thus 0.1 moles of [tex]Fe_2O_3[tex] are produced by =[tex]\frac{67.2}{2}\times 0.1=3.36L[/tex] of [tex]O_2[/tex]
b. [tex]3\times 22.4L=67.2L[/tex] of [tex]O_2[/tex] react with = [tex]4\times 55.8=223.2g[/tex] of iron
Thus 10.0 L of [tex]O_2[/tex] react with = [tex]\frac{223.2}{67.2}\times 10=33.2g[/tex] of iron
Order the sequence of steps that occur when you add heat to a chemical reaction. Place these steps in a logical order keeping in mind how adding temperature affects the rate of reaction.
The reaction rate of the experiment is recorded and found to have occurred at a faster rate than it did without the addition of heat.
Temperature increases due to the higher ketic energy of particles.
Two chemicals are mixed together and slowly some bubbles appeanr
Heat is added to the experiment with a Bunsen burner.
More collisions of particles occurs due to the increased kinetic energy.
Answer:
C,A,B,D
Explanation:
That's the correct order, hope this helps
State the postulate of Bohr theory
Answer:
Bohr's model of the hydrogen atom is based on three postulates:
1) An electron moves around the nucleus in a circular orbit,
2) An electron's angular momentum in the orbit is quantised,
3) The change in an electron's energy as it makes a quantum jump from one orbit to another is always accompanied by the emission or absorption of a photon. Bohr's model is semi-classical because it combines the classical concept of electron orbit (postulate 1) with the new concept of quantisation ( postulates 2 and ).
Please help I’m so confused on this it’s stoichiometry
Answer:
48.27g Na
Explanation:
To start we need to balance the equation. The trick is to make sure both sides have equal amounts of each atom:
2Na + Cl2 --> 2NaCl
Now we can use sociometry
We have 75 g of Cl2, and for every 1 mole of Cl2, there are 70.9 grams:
[tex]75g Cl2 * \frac{1mole Cl2}{70.9g Cl2}= 1.05 mole Cl2[/tex]
Now we have moles of Cl2. To get to grams of Na, we need to first use mole to mole ratio:
[tex]1.05mole Cl2 *\frac{2 mole Na}{1 mole Cl2} =2.1 mole Na[/tex]
From here we convert moles of Na into grams of Na
[tex]2.1mol Na*\frac{22.99g Na}{1 mole Na} = 48.27g Na[/tex]
It's usually easier to just make one singular equation with all of these smaller equations.
[tex]75gNa*\frac{1molCl2}{70.9gCl2} *\frac{2mol Na}{1 mol Cl2} *\frac{22.99g Na}{1 mol Na}=48.27 gNa[/tex]
The trick to sociometry is making sure your units cancel out until you only have the unit you want. If there are moles of Na in the numerator, there needs to be moles of Na in the denominator. If there are grams of Cl2 in the numerator, there needs to be grams of Cl2 in the denominator and so one and so on
What is the molecular formula for a compound that is 44.87% potassium, 36.7%
oxygen, 18.0% sulfur and a molecular mass of 696g.
Answer:
Molecular formula: S4K8O16 empirical formula: SK2O4
Explanation:
First we find the moles of each by first finding grams (using the percent) and then using stoichiometry to convert into moles:
Sulfur: 696 *.18 = 125.28grams S* [tex]\frac{1 mole S}{32.065 g S} = 3.907 moles S[/tex]
Potassium: 696 *.4487 = 312.2952 *[tex]\frac{1 mole K}{39.08 g K}[/tex]= 7.99117 mole K
Oxygen: 696 * .367 = 255.432 * [tex]\frac{1 mol O}{16g O}[/tex] = 15.9654 mole O
Then we divide each value by the atom with the smallest number of moles to find the mole ratio:
3.907/3.907= 1
7.99117 mole K/ 3.907= 2.043
15.9654 mole O/ 3.907= 4.08
The empirical formula is SK2O4
To find the molecular formula, we divide the mass given (696) by the mass of the empirical formula (174.22) to get 4. We then divide each atom by 4.
Molecular formula: S4K8O16
The hydrolysis of adenosine triphosphate (ATP) is represented by the equation below. This reaction is critically important in cellular biology, but the reaction itself proceeds at a very slow rate. Based on the information given, which of the following best explains why an enzyme (biological catalyst) is required for the reaction to occur at a faster rate?
ATP+ H2O ADP+ Pi
ΔG= -30.5Kj/mol
a. Because ΔG < 0, the hydrolysis of ATP is not thermodynamically favorable. In cells, ΔS is increased by increasing the amount of H2O consumed, resulting in ΔG >0 and an increase in the reaction rate.
b. Because ΔG < 0, the hydrolysis of ATP is not thermodynamically favorable. In cells, enzymes act as catalysts that decrease ΔH for the reaction, resulting in ΔG >0 and an increase in the reaction rate.
c. Although the hydrolysis of ATP is thermodynamically favorable, without a catalyst the reaction occurs at a very slow rate because it has a small activation energy.
d. Although the hydrolysis of ATP is thermodynamically favorable, without a catalyst the reaction occurs at a very slow rate because it has a large activation energy.
Answer:
d. Although the hydrolysis of ATP is thermodynamically favorable, without a catalyst the reaction occurs at a very slow rate because it has a large activation energy.
Explanation:
Hello!
In this case, since negative Gibbs free energies of reaction stand for thermodynamically favored processes, we can immediately rule out choices a. and b.
Moreover, since the reaction is slow without the presence of a catalyst, which the context of biochemistry is an enzyme, we infer that correct choice is d. Although the hydrolysis of ATP is thermodynamically favorable, without a catalyst the reaction occurs at a very slow rate because it has a large activation energy because the higher the activation energy the slower the reaction according to the Arrhenius equation.
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can you help me with my science
Gold is yellow, shiny, smooth, and is found in the ground. A geologist finds a material that she thinks may be gold. Which of the following tests would reveal that
the material is not gold and not an element?
A. Its density is different from that of gold.
B. Its melting point is different from that of gold.
C. The material is composed of two different substances.
D. Its boiling point differs from that of gold.
A combustion reaction involves the reaction of a substance with oxygen gas. The complete combustion of any hydrocarbon (binary compound of carbon and hydrogen) produces carbon dioxide and water as the only products. Heptane is a hydrocarbon that is found in gasoline. Complete combustion of heptane produces 7 liters of carbon dioxide for every 8 liters of water vapor (both measured at the same temperature and pressure). What is the ratio of carbon atoms to hydrogen atoms in a molecule of heptane
Answer:
7/16
Explanation:
The general formula for the combustion of alkanes is;
CnH2n+2 + 3n+1/2 O2 -------> nCO2 + (n+1)H2O
So, we have;
CnHn + nO2 ------> 7CO2 + 8H2O
So there are 7 carbon atoms and 16 hydrogen atoms in heptane according to the law of conservation of mass.
Therefore, heptane is; C7H16
The ratio of carbon to hydrogen is now; 7/16
Decide whether a chemical reaction happens in either of the following situations. If a reaction does happen, write the chemical equation for it. Be sure your chemical equation is balanced and has physical state symbols. situation chemical reaction.
A strip of solid magnesium metal is put into a beaker of 0.042M SnCl3 solution.
Answer: [tex]3Mg(s)+2SnCl_3(aq)\rightarrow 3MgCl_2(aq)+2Sn(s)[/tex]
Explanation:
Single replacement reaction is a chemical reaction in which more reactive element displaces the less reactive element from its salt solution.
A more reactive element is one which can easily lose or gain electrons as compared to the other element.
As Magnesium is more reactive than tin, it can easily displace tin from its salt solution [tex](SnCl_3)[/tex] and form magnesium chloride and tin in elemental form.
The balanced chemical equation is:
[tex]3Mg(s)+2SnCl_3(aq)\rightarrow 3MgCl_2(aq)+2Sn(s)[/tex]
Put these elements in order of decreasing electronegativity, with the highest electronegative element as number 1.
a. tin (Sn, Group 14, Period 5)
b. rubidium (Rb, Group 1, Period 5)
c. bromine (Br, Group 17, Period 4)
d. lithium (Li, Group 1, Period 2)
e. cadmium (Cd, Group 12, Period 5)
Answer:the answer is a c and e
Explanation:
A balloon full of air has a volume of 1.00L at a temperature of 23 °C. What is the balloon's volume at 33°C?
Answer:1.03L
How do I solve this?
Answer:
V2= 1.03L
Explanation:
Start off with what you are given.
V^1: 1.00L
T^1: 23°C
V^2?
T^2: 33°C
If you know your gas laws, you have to utilise a certain gas law called Charles' Law:
V^1/T^1 = V^2/T^2
Remember to convert Celsius values to Kelvin whenever you are dealing with gas problems. This can be done by adding 273 to whatever value in Celsius you have.
(23+273 = 296) (33+273 = 306)
Multiply crisscross
1.00/296= V^2/306
296V^2 = 306
Dividing both sides by 296 to isolate V2, we get
306/296 = 1.0337837837837837837837837837838
V2= 1.03L
An element X has a triiodide with the empirical formula XI3 and a trichloride with the empirical formula XCl3. The triiodide is converted to the trichloride according to the equation XI3 Cl2XCl3 I2 If the complete conversion of 1.196 g of XI3 results in the formation of 0.436 g of XCl3, what is the atomic mass of the element X
Answer:
51.03g/mol is the molar mass of X
Explanation:
Based on the reaction:
2XI₃ + 3Cl₂X → 2XCl₃ + 3I₂
Where 2 moles of XI₃ reacts to produce 2 moles of XCl₃ -The ratio of reaction is 1:1-
To solve this question we must find the mass of X per mole (This is the atomic mass of X).
As the moles of both compounds are the same:
1.196g / 0.436g = Molar mass XI₃ / molar mass XCl₃ (1)
Also:
Molar mass XI₃ = Molar mass X + 380.71g/mol
Molar mass XCl₃ = Molar mass X + 106.36g/mol
Replacing in (1):
2.7431 = (Molar mass X + 380.71g/mol) / (Molar mass X + 106.36g/mol)
2.7431 Molar mass X + 291.76g/mol = Molar mass X + 380.71g/mol
1.7431 Molar mass X = 88.95g/mol
Molar mass X = 51.03g/mol
51.03g/mol is the molar mass of XHow many moles in 6.57 x 10^24 formula units of NaCl?
0.092 moles
10.91 moles
3.96 X 10^49 moles
145 moles
Answer:
3.955*10^48
Explanation:
1 mole of a substance gives 6.02*10^23/6.57*10^24 will give x then cross multiply the answer. is 3.955*10^48
anyone wanna do my chem test for 500 points? my insta is niqsariot_1 hmu if your interested and for everyone else FREE 100 POINTS
Answer:
I would be if I do it your no learning anything but I would but I don't have insta yet
Explanation:
sorry
Answer:
k
Explanation:
The PH of a solution of Hcl is 2.find out the amount of acid present in a litre of the solution
Answer:
The solution is 10^-2 or 0.01M in HCl.
Explanation:
meaning of pH is "power of hydrogen".
what is the molar concentration of a HCl solution with pH=2?
Let say pH=2
[H+]=10^-2M
HCL is a strong acid that dissociates completely:
[H+]=[HCL]
Therefore solution is 10^-2 or 0.01M in HCL.
Which statement describes the movement of the medium by a transverse wave?
A. at an obtuse angle to the wave
B. parallel to the wave
C. at a right angle to the wave
D. at an acute angle to the wave
Answer:
A
Explanation:
But I'm not sure just my instinct
The statement that described the movement of the medium via the transverse wave should be that it should be parallel to the wave.
What is a transverse wave?It is the waves in which the motion considered all the points that should be on the wave oscillate along the paths at the right angles with respect to the wave of the direction. An example of this kind of wave should be electromagnetic, etc. Here, the movement should be parallel to the wave.
Hence, the correct option is b.
Learn more about transverse wave here: https://brainly.com/question/21890036
A 1,900-m3 water tower has been cleaned with a chlorine solution. The vapors of chlorine in the tower exceed allowable concentrations for the work crew to enter and finish repairs. If the chlorine concentration is 15 mg/m3 and the allowable concentration is 0.0015 mg/L, how long must the workers vent the tank with clean air flowing at 2.35 m3/s
Answer:
t = 1862 s
Explanation:
To do this, we need first to determine the theorical detention time, which can be determined with the following expression:
t₀ = ∀/Q (1)
Where:
t₀: detention time
∀: Volume of the fluid in the reactor
Q: Flow rate in the reactor
With this time, we must use the following expression to determine the time that the workers will take to vent the tank:
C = C₀ e^(-t/t₀) (2)
From here, we must solve for time t, and the expression will be:
t = ln(C₀/C) * t₀ (3)
Now that we know the expression to use, let's solve for t. Using (1) to determine the detention time, ∀ is 1900 m³, and Q is 2.35 m³/s so:
t₀ = 1900 / 2.35 = 808.51 s
Now, let's solve for the time t. C will be 0.0015 mg/L (or 1.5 mg/m³ cause in 1 m³ we have 1000 L) and C₀ 15 mg/m³:
t = ln(15/1.5) * 808.51
t = 1861.66 s or simply 1862 sHope this helps
Need help fast help help help. Help
Answer:
fjnjfzgnf
Explanation:
Answer:
it blank !
Explanation:
How much of NaCl is in 1.14 L of 0.400 M
NaCl?
Answer:
44 g NaCI
Explanation:
The problem provides you with the molarity and volume of the target solution, so your first step here will be to use this information to figure out how many moles of sodium chloride.
2NH3+2O2- N2o+3H2O
If 80.0 grams of O2 are reacted in the above reaction,how many grams of N2O will be produced?
Answer:
55.025g of N2O
Explanation:
2 NH3 + 2 O2 → N2O + 3 H2O
moles of O2 = 80.0/32 = 2.5 moles O2
moles of N2O = 2.5 moles O2 * 1 mole N2O
= 1.25 moles N2O
moles = mass/Molar mass
mass = moles * Molar mass = 1.25 x 44.02 = 55.025 g
Help please !!!!!!! 10 points for this
what is used to create motion
Answer:
These forces make objects change their motion or movement , the act of going from one place to another.
Explanation:
(feso4.(Nh4) So4. 6H2o) +Kmno4+H2So4_Fe2(So4)3+K2So4+mnSo4+(Nh4)2So4+H2o
Answer:
balancing the equation?
If someone is building a scale model of our solar system which characteristic would be the most difficult to build into the model?
1#The relative sizes of the objects
2#The colors of the objects
3#The distances between objects
4#The composition of the objects
Answer:
The composition of the objects because not all the planets have been explored
515282 quarts into milliliters. I
Answer:
487638640,7819
dndndnndndbxbdbdbdbdb
When a substance breaks up into two simpler substances, the reaction
is an)
reaction.
Answer:
Decomposition.
Explanation:
Decomposition Reactions T hose reactions in which a single substance (reactant) splits up into two or more simpler substances (products) are known as decomposition reactions. These reactions are carried out by supplying energy in form of heat, electricity or light which breaks that substance into simpler substances
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DUE IN 5 MINUTES CHEMISTRY DIMENSIONAL ANALYSIS
In 2009, Usain Bolt ran 100 meters in 9.58 seconds. What is this speed in km/hr? (!! DIMENSIONAL ANALYSIS!! NOT A REGULAR PROBLEM)
plzzzzzzz help asap its just one question plzzzzz its in the file <3
Answer:
There are 6 atoms of oxygen in 2Ca(NO3)2
How many grams of sodium (Na) are in 6.2 mol of Na?
mass = mol no. x molar mass
= 6.2 x 23
= 142.6 g
