The old age of rock when examined is 21.4 million years if the ratio of uranium-235 to lead-207 is found to be 125,000:875,000. the half-life of uranium-235 is 700 million years.
Decaying EquationP = [P + D] (1/2) ^(t/t(1/2))
where,
P represent the present parent amount
D is the present daughter amount
t(1/2) is the half life time period
t is the actual age
We know that,
t = (log[(P+D) /P] / log2) × t(1/2) ----------(1)
Given,
P = 97.6
D = 2.1
Ratio of P and D can be calculated as
P/D = 97.6/2.1
= 46.476
By substituting all the values in eq(1), we get
t = [(log 46.476 +1)/log2] × t(1/2)
Given,
The half life of U —Pb decay is 700 million years.
So,
t = [(log 46.476 +1)/log2] × 700
t = 21.4 million years.
Thus, we calculated that the the old age of rock when examined is 21.4 million years.
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DISCLAIMER:
The given question is misprint on portal.
Here is the correct form of question:
A rock is examined to determine its age, and the ratio of uranium-235 to lead-207 is found to be 125,000:875,000. the half-life of uranium-235 is 700 million years.
How old is the rock if it contains Uranium-235/ lead-207 ratio of 97.6 to 2.1?
If two wave crests overlap each other and one has an amplitude of 5 and the other has an amplitude of 3, what is the interference that is created?
Answer:
The interference is 8
Explanation:
Help with number 4??????????? Asap
Answer:
it's A I think
Explanation:
hope u pass on this homework
Given the density of 1.2 g/mL and a volume 7.8 mL. What is the mass? Round to the nearest 0.1.
Answer:
here is my answerrrrrrr
True or False: A polymer is a complex molecule made from smaller,
repeating molecules bonded together.
Which stage of the cell cycle results in two identical cells?
mitosis
cytokinesis
interphase
metaphase
Answer:
B.
Explanation:
Which types of changes must follow the law of conservation of mass? (2 points)
O Both physical and chemical changes
O Neither physical nor chemical changes
O Only physical changes
O Only chemical change
ca2 -calmodulin-dependent facilitation and ca2 inactivation of ca2 release-activated ca2 channels
This article aims to find that [tex]Ca^{2+}[/tex] occupancy of a site on the extracellular side of the CRAC channel ordinarily potentiates its [tex]Ca^{2+}[/tex] as well as [tex]Na^{+}[/tex] currents, and [tex]Ca^{2+}[/tex] dissociation from this site is responsible for the inactivation of its [tex]Na^{+}[/tex] current.
The most extensively studied of the store-operated ion channels, which are widely expressed and crucial to many vital biological processes, is the [tex]Ca^{2+}[/tex] release-activated [tex]Ca^{2+}[/tex] (CRAC) channel. But little is known about the CRAC channel's molecular makeup or how intracellular or extracellular messengers control it.
It becomes more permeable to monovalent cations with a higher current when extracellular divalent cations are absent, however this monovalent cation current quickly deactivates due to an unidentified mechanism.
Here, it was found that [tex]Ca^{2+}[/tex] occupancy of a site on the extracellular side of the CRAC channel ordinarily potentiates both its [tex]Ca^{2+}[/tex] and [tex]Na^{+}[/tex] currents. [tex]Ca^{2+}[/tex] dissociation from this site, however, results in the inactivation of the channel's [tex]Na^{+}[/tex] current. This [tex]Ca^{2+}[/tex]-dependent potentiation is required for the normal functioning of CRAC channels.
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What are some molecular compounds that we use in everyday life and their products?
Ex: Kirkland water - dihydrogen monoxide; H2O
Answer:
Water. Chemical Formula: H2O.
Table Salt. Chemical Formula: NaCl.
Sucrose (Sugar) Chemical Formula: C12H22O11.
Soaps. Chemical Formula: RCOO–Na, Where R is a long chain of carbon atoms ranging from 16-18 in number.
Toothpaste. Chemical Formula: CaCO3 or NaF.
Explanation:
how many electrons does cobalt lose/donate?
Answer:
Cobalt lose 3 electrons and donate 12 electrons.
Explanation:
In the periodic table,cobalt has nine electrons .It has lost 3 electrons,so it is only six left.Once it forms the complex,each ammonia donates a pair of electrons.
You are on a road trip to San Francisco. You drove 200 miles in 3 hours, and then stopped for lunch for
30 minutes. After lunch, you traveled 150 miles in an hour and a half. What was your average speed
for this trip? SHOW YOUR WORK!
a. Calculate the average speed including the time spent for lunch.
b. Calculate the average speed without the lunch stop
Answer:
Explanation:
a)
Average speed is total distance over change in time.
So
total distance=(200+150)
=350
total time=(3+0.5+1.5)
=5
350 km/5 hours
70km/hour
Therefore:
70 km/h is the average speed
b)
total distance=(200+150)
=350
total time=(3+1.5)
=4.5
350/4.5
=approx. 77.77 km/hour
Therefore:
77.77/hour is the average speed
Don't know if you round but uh yeah
Use the portion of the periodic table shown at the bottom to answer the questions.
Part 1: Name two elements that have the same properties as magnesium (Mg).
Part 2: Determine the number of protons, electrons, and neutrons present in an atom of potassium (K). Explain how you determined your answer using complete sentences.
Answer:
Part 1 calcium and strontium have same properties as magnesium because all three are in same group.
Part 2 As atomic number of potassium is 19 so it contains 19 protons and 19 electrons because it is neutral
Potassium has 20 neutrons because its mass is 39
We can find neutron = atomic mass - atomic number
Explanation:
The kinetic energy of an object can be determined using the equation , where is the kinetic energy, is the mass, and is the speed of the object. What is the mass of an object moving at a speed of 12 that has 36 J of kinetic energy?
Answer:
0.5kg
Explanation:
Given parameters:
Speed of the object = 12m/s
Kinetic energy = 36J
Unknown:
Mass of the object = ?
Solution:
Kinetic energy is the energy due to the motion of a body. It is mathematically expressed as;
K.E = [tex]\frac{1}{2}[/tex] m v²
Insert the parameters and solve;
36 = [tex]\frac{1}{2}[/tex] x m x 12²
36 = 72m
m = 0.5kg
What is incorrect in the structure? Check all that apply. The middle hydrogen is surrounded by 4 electrons. Oxygen is surrounded by 8 electrons. The middle hydrogen is bonded to 2 elements. There are too many electrons in the final structure.
Answer: The middle hydrogen is surrounded by 4 electrons, the middle hydrogen is bonded to 2 elements, and there are too many electrons in the final structure are correct.
Explanation: I just did this question and got the correct answers.
The incomplete points about the structure H—H-O: is that the middle hydrogen is surrounded by 4 electrons, the middle hydrogen is bonded to 2 elements, and there are too many electrons in the final structure are correct.
For better understanding let's explain the Lewis structure
Lewis Structure is simply showing or the representation of a molecule that tell use how the valence electrons are putt in place (arrange) among the atoms in the molecule.From the above we can therefore say that the answer The incomplete points about the structure H—H-O: is that the middle hydrogen is surrounded by 4 electrons, the middle hydrogen is bonded to 2 elements, and there are too many electrons in the final structure, is correct.
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what is the Transfer of energy from one object to another through direct contact?
Answer:]
Conduction is the transfer of energy from one molecule to another by direct contact. This transfer occurs when molecules hit against each other, similar to a game of pool where one moving ball strikes another, causing the second to move.
Explanation:
A marble is given potential energy by being placed at Location W. When the marble released, it rolls down the track.
At which location does the marble have maximum kinetic energy?
A Location w
B Location X
C Location Y
D Location 2
Answer:the answer is c , location Y
The location at which the marble have maximum kinetic energy is location Y.
What is conservation of energy?Conservation of energy states that total energy of the system doen not change else the one form of energy is converted into another form within the system.
In the given diagram it is mention that potential energy of marble is highest at the location W as potential energy is directly proportional to the height. But when the marble rolls down it attains the kinetic energy and potential energy decreases.
According to the law of conservation at point Y potential energy is minimum, so that kinetic energy becomes maximum at this point.
Hence at location Y marble have maximum kinetic energy.
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What is the charge of Aluminum?
O +3
0 -3
OO
O +1
Answer:
+ 3
Explanation:
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What do the superscripts in an electron configuration represent?
Answer: number of electron in respective sub shell or orbital
Explanation:
In an electron configuration, the superscripts (written as numbers above the orbital symbols) represent the number of electrons present in each orbital. They indicate the distribution of electrons among different energy levels and sublevels within an atom.
What are superscripts?Superscripts are characters or numbers that are positioned slightly above the normal line of text. They are typically smaller in size and are used to indicate various types of information or formatting in written text.
The superscripts are determined based on the rules of filling electron orbitals, such as the Pauli exclusion principle and Hund's rule. These rules govern the arrangement of electrons in the orbitals according to their energy levels and sublevels.
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What is the difference between elements and compounds?
186km at 3:00 the speed limit is 65km/h
He will arrive at the second city on time
Using the formula for calculating speed expressed as:
Distance = Speed * time
Given the following parameters
Speed = 65km/hr
Time = 3 hours (from noon to 3PM)
Get the distance covered by Isaiah;
Distance = 65 * 3
Distance = 195km > 186km
Since the distance covered by Isaiah is greater than the distance from one city to another city, hence he will arrive at the second city on time
What is Speed?
The speed at which an object's location changes in any direction. The distance traveled in relation to the time it took to travel that distance is how speed is defined. Since speed simply has a direction and no magnitude, it is a scalar quantity.
Therefore,
186km at 3:00 the speed limit is 65km/h
He will arrive at the second city on time
Using the formula for calculating speed expressed as:
Distance = Speed * time
Given the following parameters
Speed = 65km/hr
Time = 3 hours (from noon to 3PM)
Get the distance covered by Isaiah;
Distance = 65 * 3
Distance = 195km > 186km
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Define "Petrifying Well".
Answer:
Explanation:
A petrifying well is a well which gives objects a stone-like appearance. If an object is placed into such a well and left there for a period of months or years, the object acquires a stony exterior.
_______: a type of nebula in which stars form
Answer:
Orion Nebula
Explanation:
That is an enormous cloud of gas and dust
Determine the kinetic energy of a 1000-kg roller coaster car that is moving with a speed of 20.0 m/s.
Answer: 200000 J
Explanation:
Formula for kinetic energy: Ek=1/2 *mv^2
m=1000 kg. v=20.0m/s
Ek=1/2 *1000*20^2
Ek=500*400
Ek=200000 J
J=joules
water interacts with polar substances like –oh groups but not with non-polar substances like methyl (−ch3) or ethyl groups (−ch2). using this information, select the molecules that will easily dissolve in water based on polarity not on size. check all that apply.
CH3OH and CH3CH2CH2OH will easily dissolve in water based on polarity not on size.
What is Polarity ?In chemistry, polarity describes the type of bonds that exist between atoms. Atoms share electrons when they join forces to form chemical bonds. When one of the atoms applies a stronger attractive force to the bond's electrons, a polar molecule is created.
For instance, the chlorine atom is slightly negatively charged while the hydrogen atom in hydrogen chloride is slightly positively charged.Water is polar due to its form even though its molecules have no net charge. The molecule's hydrogen ends are positive, and its oxygen ends are negative. Water molecules are drawn to other polar molecules and to one another as a result.Learn more about Polarity here:
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Is the substance in the chart a metal or non metal? Explain.
Answer:
Nonmetal
Explanation:
A substance in the chart is a nonmetal because nonmetals are not water soluble, they are poor conductors of heat and electricity and they do not have high melting points like metals.
Can someone explain a method to help convert different units of measurement to another? For example, centimeters to kiloliters? My teacher uses a chart method but it's a little confusing. Can anyone help?
Answer:
Compare your two units. The two units must measure the same thing.
For example, in the problem "convert 2 inches into centimeters," both inches and centimeters measure length. If your units measure two different things (like length and weight), you can't convert between them.
or
Look up the conversion. Before you can do the math, you need to know how much larger one unit is than the other.If the conversion you find has many decimal places, round to the nearest significant digit. If you don't know what a significant digit is, round to the second or third digit.
For example, if you need to convert 2 inches to centimeters, you need to know that 1 inch = 2.54 centimeters.
Explanation:
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How many grarns would 3 moles of carbon dioxide (CO2) weigh? (round to the
nearest whole number)
Your answer
Mass of CO₂ = 132 g
Further explanationA mole is a number of particles(atoms, molecules, ions) in a substance
This refers to the atomic total of the 12 gr C-12 which is equal to 6.02.10²³, so 1 mole = 6.02.10²³ particles
Can be formulated :
N = n x No
N = number of particles
n = mol
No = 6.02.10²³ = Avogadro's number
mole also can be formulated :
[tex]\tt n=\dfrac{mass}{MW}[/tex]
moles of CO₂ = 3
mass of CO₂(MW=44.01 g/mol) :
[tex]\tt mass=mol\times MW\\\\mass=3\times 44.01\\\\mass=132.03~g\approx 132~g[/tex]
A reaction is found to have an activation energy of 108 kj/mol. If the rate constant for this reaction is 4. 60 × 10-6 s-1 at 275 k, what is the rate constant at 366 k?.
The rate constant at 366K is 0.58 s⁻¹.
Ea = 108 kJ/mol = 108000 J/mol; an activation energy of a reaction
T₁ = 275 K
k₁ = 4.60 × 10⁻⁶ 1/s; the rate constant at 275 K
T₂ = 366 K
R = 8.314 J/Kmol
k₂ = ?; the rate constant at 366 K
Arrhenius equation: ln(k₁/k₂) = Ea/R (1/T₂ - 1/T₁)
ln(4.60 × 10⁻⁶s⁻¹/k₂) = 108000 J/mol/8.314 J/Kmol × (1/366K - 1/275K)
k₂ = 0.58 s⁻¹
For all chemical reaction some energy is required and that energy is called activation energy (energy that needs to be absorbed for a chemical reaction to start).
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Why is the Law of Conservation of Mass a law, rather than a theory?
A. It has more scientific evidence supporting it
B. It has both independent and dependent variables
C. It has been tested with the latest laboratory balances, which are very accurate
D. It describes a repeatedly observed relationship, but it does not offer an exclamation
Answer: During a chemical reaction, matter cannot be created nor destroyed, matter can change form through physical and chemical changes, but through any of these changes, matter is conserved; even though the matter may change from one form to another, the same number of atoms exists before and after the change takes place.
Explanation: <3
A 25.0 mL sample of 0.100 M lactic acid (HC3H503, Ka = 1.4 E-4) is titrated with 0.100 M NaOH solution. Calculate the pH of the resulting
solution after 0.0ml of NaOH have been added
why is our use of electric power increasing?