g Consider (12.5 A) micro-grams of a radioactive isotope with a mass number of (78 B) and a half-life of (32.6 C) million years. If energy released in each decay is 32.6 keV, determine the total energy released in joules (J) in 1 (one) year. Give your answer with three significant figures.
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
Worth 100 points plus ill mark brainliest
How many grams of sodium phosphate ( Na₃PO₄ )are required to make 125 milliliters of a 0.240 Molar solution?
4.92
6.48
8.44
12.5
Answer:
4.92 grams of sodium phosphate (Na₃PO₄) are required to make 125 milliliters of a 0.240 M.
Explanation:
Molarity is a measure of concentration that indicates the number of moles of solute that are dissolved in a given volume.
The molarity of a solution is calculated by dividing the moles of the solute by the volume of the solution:
[tex]Molarity=\frac{number of moles}{volume}[/tex]
Molarity is expressed in units [tex]\frac{moles}{liter}[/tex].
In this case:
Molarity= 0.240 Mnumber of moles= ?volume= 125 mL= 0.125 LReplacing in the definition of molarity:
[tex]0.240 M=\frac{number of moles}{0.125 L}[/tex]
Solving:
number of moles= 0.240 M*0.125 L
number of moles= 0.03 moles
Being the molar mass of sodium phosphate 164 g/mole, that is, the mass of one mole of the compound, you can calculate the mass of 0.03 moles using the following rule of three: if 1 mole of the compound has 164 grams, 0.03 moles contains how much mass?
[tex]mass=\frac{0.03 moles*164 grams}{1 mole}[/tex]
mass= 4.92 grams
4.92 grams of sodium phosphate (Na₃PO₄) are required to make 125 milliliters of a 0.240 M.
8. The density of a gas at 350 C is 0,087 g/L. Compute the density at STP.
Answer:
0.20 g/L
Explanation:
Step 1: Calculate the molar mass of the gas (M)
At T = 350 °C = 623 K and P = 1 atm (we will assume this data), the density (ρ) of the gas is 0.087 g/L. We can calculate the molar mass of the gas using the following expression.
ρ = P × M/R × T
M = ρ × R × T/P
M = 0.087 g/L × (0.0821 atm.L/mol.K) × 623 K/1 atm = 4.5 g/mol
Step 2: Calculate the density of the gas at STP
At standard temperature (T = 273.15 K) and standard pressure (P = 1 atm), the density of the gas is:
ρ = P × M/R × T
ρ = 1 atm × 4.5 g/mol /(0.0821 atm.L/mol.K) × 273.15 K = 0.20 g/L
Question 3
Which of the objects on the shelf has the greatest inertia?
10 kg
5 kg
2kg
a
b
2 kg
5 kg
10 kg
С
d
The all have the same inertia
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
C3H8, + 5O2
+ 5O2,3CO2 + 4H20
If 2.50 moles of C3H8react, how many moles of H20 are produced?
Answer:
[tex]from \: the \: equation \\ 1 \: moles \: of \: propane \: produce \: 4 \: moles \: of \: water \\ 2.50 \:moles \: of \: propane \: will \: produce \: ( \frac{(2.50 \times 4)}{1} ) \: moles \\ = 10 \: moles \: of \: water[/tex]
One gallon of gasoline (C8H18) weights about 6.3 pounds. Burning gasoline with excess of oxygen forms water and carbon dioxide. When 3.1 gallons of gasoline burn, how many pounds of CO2 emit into the air?
FW: C = 12; H = 1; O = 16.
Answer:
60 pounds of CO₂ are emited into the air
Explanation:
The combustion of gasoline occurs as follows:
C₈H₁₈(l) + 25/2O₂(g) ⇄ 8CO₂(g) + 9H₂O
Where 1 mole of gasoline produce 8 moles of CO₂
To solve this question we must find the moles of gasoline in 3.1 gallons. 8 times these moles are the moles of CO₂ produced. With the moles of CO₂ we can find its pounds as follows:
Pounds gasoline:
3.1 gallons * (6.3 pounds / gallon) = 19.53 pounds
Grams gasoline:
19.53 pounds * (453.592g / pound) = 8859g
Moles gasoline -Molar mass C8H18: 114.23g/mol-
8859g * (1mol / 114.23g) = 77.55 moles gasoline
Moles CO₂:
77.55 moles gasoline * (8 mol CO₂ / mol Gasoline) = 620.4 moles CO₂
Mass CO₂ - Molar mass: 44.01g/mol-
620.4 moles CO₂ * (44.01g / mol) = 27304g CO₂
Pounds CO₂:
27304g CO₂ * (1lb / 453.592g) =
60 pounds of CO₂ are emited into the air
What is the energy of an electron in a Li+ ion when an electron moves from n = 2 to n =3?
Answer:
The question wants you to determine the energy that the incoming photon must have in order to allow the electron that absorbs it to jump from
n
i
=
2
to
n
f
=
6
.
A good starting point here will be to calculate the energy of the photon emitted when the electron falls from
n
i
=
6
to
n
f
=
2
by using the Rydberg equation.
1
λ
=
R
⋅
(
1
n
2
f
−
1
n
2
i
)
Here
λ
si the wavelength of the emittted photon
R
is the Rydberg constant, equal to
1.097
⋅
10
7
m
−
1
Plug in your values to find
1
λ
=
1.097
⋅
10
7
.
m
−
1
⋅
(
1
2
2
−
1
6
2
)
1
λ
=
2.4378
⋅
10
6
.
m
−
1
This means that you have
λ
=
4.10
⋅
10
−
7
.
m
So, you know that when an electron falls from
n
i
=
6
to
n
f
=
2
, a photon of wavelength
410 nm
is emitted. This implies that in order for the electron to jump from
n
i
=
2
to
n
f
=
6
, it must absorb a photon of the same wavelength.
What is the minimum temperature
needed to dissolve 35 grams of KCl in 100 grams of water?
Answer:
[tex]30^{\circ}\text{C}[/tex]
Explanation:
To know the temperature at which KCl dissolves in water we need to refer to the general solubility curves.
In the case of [tex]KCl[/tex], [tex]35\ \text{g}[/tex] of it will dissolve in [tex]100\ \text{g}[/tex] of water at a minimum temperature of [tex]30^{\circ}\text{C}[/tex].
So, the the minimum temperature needed to dissolve 35 grams of KCl in 100 grams of water is [tex]30^{\circ}\text{C}[/tex].
What is the pressure inside a container of 3 moles of gas with a volume of 60 Liters at a temperature of 400 K?
I just need the answer not a link please :)
_FeCI3 + _ NaOH = _ NaCI + _Fe(OH)3 balance and strength the coefficients for each substance
Answer:
FeCl₃ + 3 NaOH ⇒ 3 NaCl + Fe(OH)₃
Explanation:
Let's consider the following unbalanced equation. This is a double displacement reaction.
FeCl₃ + NaOH ⇒ NaCl + Fe(OH)₃
We will start balancing Cl atoms by multiplying NaCl by 3.
FeCl₃ + NaOH ⇒ 3 NaCl + Fe(OH)₃
Then, we will get the balanced equation by multiplying NaOH by 3.
FeCl₃ + 3 NaOH ⇒ 3 NaCl + Fe(OH)₃
Help hurry please !!!!!
The oxidation state for Cl is A. -1 as a reactant and +1 as a product B. -1 as a reactant and 0 as a product C. -1 as a reactant and -1 as a product D. +1 as a reactant and +1 as a product
Answer:
no sure
Explanation:
3.A binary mixture consisting of 50.7 mol % n-butane (1) and the balance iso-butane (2) enters a flash chamber operating at 9.6 bar and 344 K. Use the truncated virial equation of state (equation 3.36 in the textbook) to estimate the composition of the vapor and liquid phases leaving the flash chamber.
Which of the following astronomical bodies would most likely be the largest?
1. A dwarf star from a nearby solar system
2. A comet
3. One of the gas giants in our solar system
4. Ganymede, the largest moon of Jupiter
Answer:
1
because a dwarf star will seemlarge because of the in ability of any human being to see d sun
Joan performed a shadow puppet play for her younger brother by shining a flashlight on paper cutouts behind a curtain. What happens to the light from the flashlight?
Answer:
The light is transmitted through the curtain.
Explanation:
I believe this might be the answer, please comment if it’s incorrect
What is the molar mass of AlCl3
Answer:
133.34 g/moles
Explanation:
but to make life easy it could be 133.4 g/ moles as well
Which of these is most likely made of pieces of rock that are weathered by water and wind?
O A diamonds
OB sand
OC grass
OD vegetables
Answer:
The answer would be sand.
Explanation:
Sand is weathered down tiny pieces of rock. Sand flows down rivers to shores and slowly builds up to form beaches.
Answer:
The Answer is gonna be B sand
A 50.0 mL sample of an aqueous H2SO4 solution is titrated with a 0.375 M NaOH solution. The equivalence point is reached with 62.5 mL of the base. The concentration of H2SO4 is ________ M. A 50.0 mL sample of an aqueous H2SO4 solution is titrated with a 0.375 M NaOH solution. The equivalence point is reached with 62.5 mL of the base. The concentration of H2SO4 is ________ M. 0.150 0.234 0.300 0.469 0.938
Answer: The concentration of [tex]H_2SO_4[/tex] is 0.234 M
Explanation:
According to the neutralization law,
[tex]n_1M_1V_1=n_2M_2V_2[/tex]
where,
[tex]n_1[/tex] = basicity [tex]H_2SO_4[/tex] = 2
[tex]M_1[/tex] = molarity of [tex]H_2SO_4[/tex] solution = ?
[tex]V_1[/tex] = volume of [tex]H_2SO_4[/tex] solution = 50.0 ml
[tex]n_2[/tex] = acidity of [tex]NaOH[/tex] = 1
[tex]M_1[/tex] = molarity of [tex]NaOH[/tex] solution = 0.375 M
[tex]V_1[/tex] = volume of [tex]NaOH[/tex] solution = 62.5 ml
Putting in the values we get:
[tex]2\times M_1\times 50.0=1\times 0.375\times 62.5[/tex]
[tex]M_1=0.234M[/tex]
Therefore concentration of [tex]H_2SO_4[/tex] is 0.234 M
How is water used in society
Answer:
Water can be used for direct and indirect purposes. Direct purposes include bathing, drinking, and cooking, while examples of indirect purposes are the use of water in processing wood to make paper and in producing steel for automobiles. The bulk of the world's water use is for agriculture, industry, and electricity.
Explanation:
Answer:
water is used for drinking, bathing, cooking, agriculture etc
Is anyone good at chemistry if so can someone help me please ?
(NO LINKS)
Question 15
We're given the [OH⁻] as 8.34 × 10⁻¹² M. Using the formula pOH = -log[OH⁻], the pOH of this solution would be -log(8.34 × 10⁻¹²) ≈ 11.08.
The pOH is, for lack of a better term, the "opposite" of pH: A pOH of 7 is neutral; a pOH less than 7 is basic; and a pOH greater than 7 is acidic.
This follows from the relation, pH + pOH = 14. In this case, with a pOH of 11.08, our pH would be 14 - 11.08 = 2.92, which is acidic (pH < 7).
Thus, the correct answer choice is B.
100.00 mL of 0.15 M nitrous acid (HNO2) are titrated with a 0.15 M NaOH solution. (a) Calculate the pH for the initial solution. (b) Calculate the pH for the point at which 80.0 mL of the base has been added. (c) Calculate the pH for the equivalence point. (d) Calculate the pH for the point at which 105 mL of the base has been added.
Answer:
a. pH = 2.04
b. pH = 3.85
c. pH = 8.06
d. pH = 11.56
Explanation:
The nitrous acid is a weak acid (Ka = 5.6x10⁻⁴) that reacts with NaOH as follows:
HNO₂ + NaOH → NaNO₂(aq) + H₂O(l)
a. At the beginning there is just a solution of 0.12M HNO₂. As Ka is:
Ka = [H⁺] [NO₂⁻] / [HNO₂]
Where [H⁺] and [NO₂⁻] ions comes from the same equilibrium ([H⁺] = [NO₂⁻] = X):
5.6x10⁻⁴ = X² / 0.15M
8.4x10⁻⁵ = X²
X = [H⁺] = 9.165x10⁻³M
As pH = -log [H⁺]
pH = 2.04b. At this point we have HNO₂ and NaNO₂ (The weak acid and the conjugate base), a buffer. The pH of a buffer is obtained using H-H equation:
pH = pKa + log [NaNO₂] / [HNO₂]
Where pH is the pH of the buffer,
pKa is -log Ka = 3.25
And [NaNO₂] [HNO₂] could be taken as the moles of each compound.
The initial moles of HNO₂ are:
0.100L * (0.15mol / L) = 0.015moles
The moles of base added are:
0.0800L * (0.15mol / L) = 0.012moles
The moles of base added = Moles of NaNO₂ produced = 0.012moles.
And the moles of HNO₂ that remains are:
0.015moles - 0.012moles = 0.003moles
Replacing in H-H equation:
pH = 3.25 + log [0.012moles] / [0.003moles]
pH = 3.85c. At equivalence point all HNO2 reacts producing NaNO₂. The volume added of NaOH must be 100mL. That means the concentration of the NaNO₂ is:
0.15M / 2 = 0.075M
The NaNO₂ is in equilibrium with water as follows:
NaNO₂(aq) + H₂O(l) ⇄ HNO₂(aq) + OH⁻(aq) + Na⁺
The equilibrium constant, kb, is:
Kb = Kw/Ka = 1x10⁻¹⁴ / 5.6x10⁻⁴ = 1.79x10⁻¹¹ = [OH⁻] [HNO₂] / [NaNO₂]
Where [OH⁻] = [HNO₂] = x
[NaNO₂] = 0.075M
1.79x10⁻¹¹ = [X] [X] / [0.075M]
1.34x10⁻¹² = X²
X = 1.16x10⁻⁶M = [OH⁻]
pOH = -log [OH-] = 5.94
pH = 14-pOH
pH = 8.06d. At this point, 5mL of NaOH are added in excess, the moles are:
5mL = 5x10⁻³L * (0.15mol / L) =7.5x10⁻⁴moles NaOH
In 100mL + 105mL = 205mL = 0.205L. [NaOH] = 7.5x10⁻⁴moles NaOH / 0.205L =
3.66x10⁻³M = [OH⁻]
pOH = 2.44
pH = 14 - pOH
pH = 11.56Do not abuse or misuse any piece of drawing instrument. ASAPPPP
What is the molarity (M) of a solution that has 0.50 moles of solute dissolved in 1.0
liter of solution?
Answer:
it is 0.50=0.5 M
Explanation:
Molarity definition is measure the concentration of solution.
and the rule is
molarity(M)= moles of solute/volume of solution in liters
Ex: 2.1 M MgCl2= 2.1 mole MgCl2/ L MgCl2 solution
10) Is the chemical equation balanced?
2 Al + Fe2O3
2Fe + Al2O3
Answer: Yes , the equation is balanced.
Explanation:
According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.
The given chemical equation is:
[tex]2Al+Fe_2O_3\rightarrow 2Fe+Al_2O_3[/tex]
As the number of atoms on reactant side is equal to the number of atoms on product side, the equation is balanced.
Balance the single replacement chemical reaction.
Explanation:
B) 3CuCl2+2AL..….2AlCl3+3Cu
hope it helps.
Balanced Equation:
3CuCl₂ + 2Al = 2AlCl₃ + 3Cu
Please balance the equation C7H16 + CoF3 = C7F16 + HF +CoF2
with solutions
b. how many grams of CH6 is needed to react with 20.0 grams of HF?
C. how many particles of CoF3 is needed to react with 40.0 grams of CzF16?
d. how many grams of CH16 will be produce from 2.03 x 10 molecule of CoFs?
e. Find the Limiting reactant and exXcess reactant in CF16?
6g of CH16
6g of CoFa
f. Find the theoretical yield from CzFi6?
g. What is the percent yield of C;F16 if the actual yield is 1.28 g ?
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:
Put the steps of the carbon cycle in order using Step 1 as your starting point.
Step 1: Bacteria, through nitrogen fixation and nitrification, convert nitrogen into a usable form.
The animal dies and decomposes, returning nitrogen back to the soil.
Once nitrogen is in usable form, it is taken up by plants and assimilated into proteins..
An animal eats a plant and the nitrogen becomes part of the animal’s proteins.
Answer:
Carbon moves from the atmosphere to plants. ...
Carbon moves from plants to animals. ...
Carbon moves from plants and animals to soils. ...
Carbon moves from living things to the atmosphere. ...
Carbon moves from fossil fuels to the atmosphere when fuels are burned. ...
Carbon moves from the atmosphere to the oceans.
Explanation:
Answer:
step 4 , 2 , 3
Explanation:
Calculate the enthalpy change for the photosynthesis of gluclose
Answer:
jhdgafhgafhagfhafg
Explanation:
