Answer:
Energy released = 18.985 J
Explanation:
The exponential decay of radioactive substance is given by -
N(t) = N₀ [tex]e^{-kt}[/tex]
where
N₀ = initial quantity
k = decay constant
Half life, [tex]t_{1/2} = \frac{ln 2}{k}[/tex]
⇒[tex]k = \frac{ln 2}{t_{1/2} }[/tex]
Given,
N₀ = 12.5 + 3 = 15.5 × 10⁻⁶ gm
[tex]t_{1/2}[/tex] = 32.6 + 18 = 50.6 × 10⁶ years
So,
[tex]k = \frac{ln 2}{50.6 * 10^{6} }[/tex] = 1.361 × 10⁻⁸ year⁻¹
Now,
N(1) = 15.5 × 10⁻⁶ [tex]e^{-1.361*10^{-8} *1}[/tex]
= 15.49999978904
Now,
Substance decayed = N₀ - N(t)
= 15.5 × 10⁻⁶ - 15.49999978904 × 10⁻⁶
= 21.095 × 10⁻¹⁷ kg
⇒Δm = 21.095 × 10⁻¹⁷ kg
So,
Energy released = Δmc²
= 21.095 × 10⁻¹⁷ × 3 ×10⁸ × 3 × 10⁸
= 189.855 ×10⁻¹
= 18.985 J
⇒Energy released = 18.985 J
How is heat transferred from one object to another? A. Heat moves from warmer objects to cooler objects. B. Heat moves from cooler objects to warmer objects. c. Heat moves between objects of the same temperature. D. Heat moves back and forth between two objects.
Answer: I believe the answer is A, heat moves from warmer objects to cooler objects. I know for sure it isn’t C or D though so A
The heat is transferred from one object to another as heat moves from warmer objects to cooler objects. The correct option is A.
What is the transfer of heat?There are three ways to transfer heat. They are conduction, convection, and radiation. Heat travels from one body to another body. If the temperature of two objects is different, then the heat travels from higher temperature to lower temperature.
Conduction is the transfer of energy when two objects ate in contact with each other. Convection is a transfer between object and environment. Radiation is when transferred by emission of electromagnetic radiation.
Thus, the correct option is A. Heat moves from warmer objects to cooler objects.
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6. A box measures 11.25 inches in length, 8.1 inches in width and 6.85 inches in height. What is the
volume of the box?
Answer:
I'd say 624.2^3 inches.
Explanation:
See if you can complete the following table using only what is on this page. Hint. Two of the entries are for the same element.
Element
Symbol
Nuclear
Symbol
Atomic Mass
Protons Neutrons
Electrons in
Number Number
Neutral Atom
57
82
138
57
ola
Fe
59
26
Answer and Explanation:
The empty spaces should be completed step-by-step as follows:
First line:
Element symbol: La (it is the corresponding element for the atomic number 57)
Mass number = Atomic number + Neutrons = 57 + 82 = 139
Nuclear symbol: ¹³⁹₅₇ La because the atomic number is 57 and mass number is 139.
Protons: 57 (is equal to the atomic number for a neutral atom)
Electrons in neutral atom = Atomic number = 57
Second line:
Element symbol: La (it is the corresponding element for the atomic number 57 and mass number 138)
Atomic number: 57 (from the Periodic Table, for La)
Mass number = 138 (from the nuclear symbol)
Protons: 57 (is equal to the atomic number for a neutral atom)
Neutrons = Mass number - Atomic number = 138 - 57 = 81
Electrons in neutral atom = Atomic number = 57
Third line:
Atomic number: 26 (from the Periodic Table, for the element Fe)
Protons: 26 (is equal to the atomic number for a neutral atom)
Neutrons = Mass number - Atomic number = 59 - 26 = 33
Nuclear symbol: ⁵⁹₂₆ Fe because the atomic number is 26 and mass number is 26.
11.9 g sample of aniline (C6H5NH2, molar mass = 93 g/mol) was combusted in a calorimeter with sufficient of oxygen. If the calorimeter heat capacity is 10.0 kJ/K, how many Kelvin does the temperature increase due to this sample combustion?
4 C6H5NH2 (l) + 35 O2 (g) --> 24 CO2 (g) + 14 H2O (g) + 4 NO2 (g)
ΔHrxn=−12800kJ
Answer:
The temperature increases in 40.9K
Explanation:
Based on the reaction, 4 moles of aniline in combustion releasing 12800kJ to the surroundings, in this case, to the calorimeter.
To solve this question we must find the heat that releases the sample of aniline finding the moles in the sample.
With the heat released we can find the increase in Kelvin due the combustion as follows:
Moles aniline:
11.9g * (1mol / 93g) = 0.128 moles aniline
Heat released:
0.128 moles Aniline * (12800kJ / 4 moles Aniline) = 409kJ are released
Increasing in temperature:
For each 10.0kJ, the calorimeter increases its temperature in 1K. For 409kJ:
409kJ * (1K / 10.0kJ) =
The temperature increases in 40.9K4. Write the chemical formula for each of the following:
Calcium oxide - Copper (II) nitrate - Ammonium chloride-
Magnesium sulphate - Copper (1) oxide - Calcium chloride.
Answer:
Calcium oxide: CaO
Copper (II) nitrate: Cu(NO₃)₂
Ammonium chloride: NH₄Cl
Magnesium sulfate: MgSO₄
Copper (I) oxide: Cu₂O
Calcium chloride: CaCl₂
Explanation:
Hello there!
In this case, according the IUPAC rules for naming this inorganic salts, whereas calcium, copper (II), ammonium, magnesium and copper (I) are the cations and oxide, nitrate, chloride and sulfate are the anions, we proceed as follows:
Calcium oxide: CaO
Copper (II) nitrate: Cu(NO₃)₂
Ammonium chloride: NH₄Cl
Magnesium sulfate: MgSO₄
Copper (I) oxide: Cu₂O
Calcium chloride: CaCl₂
Best regards!
how many molecules are in 4.08 moles of CCL4
If a dog has a mass of 21.5 kg, what is its mass in the following units? Use scientific notation in all of your answers.
What is the dog’s mass in grams?
What is the dog’s mass in milligrams?
What is the dog’s mass in micrograms?
Explanation:
use the conversation in the image
POINTSSS AND BRAINLIEST IF YOU ANSWER CORRECTLY!!! Write about the law of conservation of energy and where light energy goes. thank you :)
Answer:
The law of conservation of energy states that the total energy is constant in any process. Energy may change in form or be transferred from one system to another, but the total remains the same.
Could you please help me with the two most recent questions of mine on my page? I will give u brainliest and 20 points! :))) X
I need help with this science problem
Answer:
I'm pretty sure its D
Explanation:
It says the best that explains. D states that when it has less energy that it the molecules will collide. And they would to make a liquid. So thats why its D.
A solution of HCl is made by dissolving .005 moles of HCl in 50 L of water. What is the pH of the solution? What is the pOH?
PH?
0.0001
4.00
11.00
2.3p
pOH?
2.00
4.00
10.00
12.00
Answer:
pH= 4; pOH= 10
Explanation:
HCl is a strong acid and therefore dissociates completely in a solution of water via HCl + H2O --> Cl- + H3O+.
Because it is a strong acid, [HCl] = [H3O+].
[HCl]= [H3O+]= (0.005 mol)/(50L)= 1.0 x 10^-4
pH= -log[H3O+]
pH= -log(1.0 x 10^-4)= 4
pH + pOH = 14
4 + pOH = 14
pOH= 10
. How many grams of lithium are formed from the reaction if you begin with 89.5
grams of copper?
Cu
+
Li2S --> 2 Li +
CUS
Answer:
179g
Explanation:
Molar ratio for Copper : Lithium is
1:2
If there are 89.5g of copper
Grams for Lithium= 89.5 × 2 = 179g of Lithium
The amount of lithium are formed from the reaction if you begin with 89.5 grams of copper is 19.6 grams.
How do we convert mass into moles?Mass can be converted into moles by using the below equation as:
n = W/M, where
W = given mass
M = molar mass
Moles of 89.5g of copper = 89.5g / 63.5g/mol = 1.4 mol
Given chemical reaction is:
Cu + Li₂S → 2Li + CuS
From the stoichiometry of the reaction, it is clear that
1.4 mole of Cu = produces 1.4 mole of CuS
1.4 mole of CuS = produced by 1.4 mole of Li₂S
1.4 mole of Li₂S = produces 2×1.4=2.8 moles of Li
Mass of 2.8 moles of Li = (2.8mol)(7g/mol) = 19.6g
Hence resultant mass of lithium is 19.6g.
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What is the maximum number of electrons that can be identified with each of following sets of quantum numbers? If there are none, enter 0.
In the process of photosynthesis, sunlight is converted into
Answer:
Chemical energy
Explanation:
By the use of electrons and protons from water
Answer:
chemical energy
Explanation:
Photosynthesis is the process by which organisms that contain the pigment chlorophyll convert light energy into chemical energy which can be stored in the molecular bonds of organic molecules (e.g., sugars). Photosynthesis powers almost all trophic chains and food webs on the Earth.
Is anyone good at chemistry if so can someone help me please ?
(NO LINKS)
As provided in the question, the pH of a solution is equal to the negative logarithm of the H₃O⁺ concentration in the solution (the square brackets denote the molar concentration).
We are given a solution with an H₃O⁺ concentration of 5.6 × 10⁻⁹ M. So, the pH of this solution would be:
pH = -log[H₃O⁺] = -log(5.6 × 10⁻⁹ M) = 8.25.
A pH that is equal to 7 is neutral; less than 7, acidic; and greater than 7, basic. As 8.25 is greater than 7, this solution is basic.
What happens to the solar energy absorbed by plants during photosynthesis ?
Answer:
Photosynthesis in plants converts solar energy into chemical energy using electrons and protons from water. in plants involves a series of steps and reactions that use solar energy, water, and carbon dioxide to produce organic compounds and oxygen.
Explanation:
Answer:
its is used to make sugar which plants eat think it goes through like glycose or something
Explanation:
how many atoms of titanium are in 11.3 moles
Answer:
I don’t mnow
Explanation:
A wave travels at 22 m/s and has a wavelength of 11 m. What is its frequency
The answer is 2Hz
To calculate frequency, divide the number of times the event occurs by the length of time.
What is the molarity of a solution created by adding 0.75 moles of lithium fluoride to 65 L of solution?
Answer:
Molarity=Moles of solute/volume of solution in Litres
Simply imputing your values
you have
0.75/65
0.0115M.
i really need help with this
Answer:
i hope i can help you with this
Answer: focus in class
Explanation:
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Which of the following is not a cation?
Iron (III) ion
sulfate
Ca²⁺
Mercurous ion
Answer:
sulfate
Explanation:
because it is anions
What is the pigment that absorbs light energy and make glucose?
Answer: chlorophyll
Explanation: Photosynthetic cells contain chlorophyll and other light-sensitive pigments that capture solar energy.
give a description of arecent (2018-2020) example of how this problem has displayed itself in your community
Answer:
im not sure go with the first
Explanation:
A cork cell was first observed by Robert Hooke in the year:
O 1556
O 1065
O 1965
O 1665
Answer:
1665
Explanation:
In 1665, Robert Hooke was the first to observe cork cells and their characteristic hexagonal shape, using the first optical microscope, which was invented by him at that time.
What is the name of the structure formed when fertilization occurs?
Answer:
zygote
Explanation:
I got this online
Answer:
ᘔYᘜOTᗴ:=> In human fertilization, a released ovum (a haploid secondary oocyte with replicate chromosome copies) and a haploid sperm cell (male gamete)—combine to form a single 2n diploid cell called the zygote.
ʰᵒᵖᵉ ⁱᵗ ʰᵉˡᵖˢ
[tex] \infty \infty [/tex]
Dominic made the table below to organize his notes about mixtures. A 1-column table. The first column labeled properties of mixtures has entries has no set composition, must have more than one state of matter, must have more than one substance. What mistake did Dominic make? The title should read “Properties of Solutions” because some mixtures do not have all of the properties listed. There is a definite recipe to make each mixture, so the composition of a mixture is set. Although it is possible to have more than one state, it is also possible to have only one state. A single substance can be used to make a mixture if the substance is composed of more than one element.
Answer:
Exxplanation:
Answer:
Although it is possible to have more than one state, it is also possible to have only one state.
Explanation:
Define a salt bridge. Question 6 options: A pathway between the cathode and anode in which ions are oxidized. A pathway by which counterions can flow between the half-cells without the solutions in the half-cell totally mixing. A pathway in which no ions flow. A pathway between the cathode and anode in which ions are reduced. A pathway, composed of salt water, that ions pass through.
Answer:
A pathway by which counterions can flow between the half-cells without the solutions in the half-cell totally mixing.
Explanation:
In a voltaic cell, oxidation occurs at the anode and reduction occurs at the cathode.
Hence, there is a build up of positive ions at the anode and a build up of negative ions at the cathode. This tends to disrupt the electrical neutrality of the half cells.
Hence, there is a need for negative ions in the salt bridge to flow towards the anode and positive ions in the salt bridge to flow towards the cathode in order to maintain the electrical neutrality of the cells.
Hence, a salt bridge provides a pathway by which counterions can flow between the half-cells without the solutions in the half-cell totally mixing.
How many atoms are there in two molecules of water?
a. 3
b.4
c.5
d.6
Answer:
the answer is 4
Explanation:
your welcome lol
PLEASE HELP IF YOU KNOW I WILL MARK BRAINLIEST!!! A LOT OF POINTS!!
What is the solubility in Molarity of Ag2SO4 in a 0.1M solution of Sodium Sulfate at 25C?
Answer:
0.0039 mol/L
The molar solubility is 0.0039 mol/L, thus the common ion effect has reduced the solubility from 0.016 mol/L for Ag2SO4 in pure water to 0.0039 mol/L in the Na2SO4 solution.
Explanation:
It takes 53.0 J to raise the temperature of an 11.0 g piece of unknown metal from 13.0∘C to 24.3 ∘C. What is the specific heat for the metal?
Answer:
Heat absorbed = mS△T
51 = ( 8.2/1000)Kg ×S (11.5)
51×1000= 8.2 (11.5)S
S = 51000/94.3
S = 540.8 J/kg K
When a chemical system is at equilibrium, A. the concentrations of the reactants are equal to the concentrations of the products. B. the concentrations of the reactants and products have reached constant values. C. the forward and reverse reactions have stopped. D. the reaction quotient, Picture, has reached a maximum. E. the reaction quotient, Picture, has reached a minimum.
Answer: The correct option is option B (the concentrations of the reactants and products have reached constant values).
Explanation:
CHEMICAL EQUILIBRIUM is defined as a state which is attained in a chemical system where by forward reaction occurs at the same rate with the backward reaction leading to CONSTANT CONCENTRATIONS of the reactants and the products. Chemical equilibrium is achievable in a closed Chemical system so that none of the reactants or products would escape be they gaseous or otherwise.
Chemical equilibrium occurs in a type of reaction called reversible reactions. Reversible reactions is one that can go in either direction depending on the condition of the system. In other words, reactants form products and under favourable conditions products react together to reform the reactants. For example,
3Fe(s) + 4H2O(l) <-------> Fe3O4(s) + 4H2(g)
As the above reversible reaction proceeds, a time is reached when the rate of forward reaction { which is the formation of Fe3O4(s) + 4H2(g)} is equal to the rate of the backward reaction {which is the formation of 3Fe(s) + 4H2O(l)}. At this point, concentrations of the reactants and products have reached constant values.
When a chemical system is at equilibrium then the concentrations of the reactants and products have reached constant values.
What is chemical equilibrium?Chemical equilibrium is a state occur in any reversible reaction, where the rate of forward reaction is equal to the rate of backward reaction and it is represent as:
A + B ⇄ C + D, where
A & B are reactants, and C & D are products.
As the rates are equal in equilibrium state, so the concentration of reactant and product also have constant value as there is no change in the rate.
Hence, option (B) is correct i.e. concentrations of the reactants and products have reached constant values.
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