Answer:
4 2/3 days
Explanation:
31.25 = 250 ( 1/2)^n solve for n
31.25/250 = 1/2 ^n log both sides to find n = 3 half lives
14 days = 3 half lives
14/3 = 4 2/3 day half life
a 125.0 mg sample of an unknown, monoprotic acid was dissolved in 100.0 ml of distilled water and titrated with a 0.050 m solution of naoh. the ph of the solution was monitored throughout the titration, and the data were collected. determine the ka of the acid and identify the unknown acid.
data-
volume of oh- added (ml), ph:
0, 3.09
5, 3.65
10, 4.10
15, 4.50
17, 4.55
18, 4.71
19, 4.94
20, 5.11
21, 5.37
22, 5.93
22.2, 6.24
22.6, 9.91
22.8, 10.2
23, 10.4
Answer:
33,666
Explanation:
is the dictionary definition of a word.
is the feeling or idea associated with a word.
A nuclear fission reaction has mass difference between the products and the reactants of 0.0593 Calculate the amount of energy released by the reaction
a. 1.09 x 10(-45)J
b. 3.28 x 10(-37)J
c. 9.85 x 10(-29)J
d. 8.86 x 10(-12)J
The amount of energy released by the reaction b. 3.28 x 10(-37)J
What is a nuclear fission reaction?A nuclear fission reaction in which the nucleus is divided into numerous small nuclei.
The mass difference is 0.0593
To calculate the energy
[tex]E = \Delta mc^2\\\\c = 3 \times 10^8\;m/s\\\\m = 3.86 \times 10^-^3 \;kg\\[/tex]
Putting the values in the equation
[tex]E = (0.0593) (3 \times 10^8\;m/s)^2 = 5.337 \times 10^1^5[/tex]
Thus, the correct option is b. 3.28 x 10(-37)J
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uranium-235 fission given: energy released = about 200 MeV per individual reaction (mass = 235 amu) find the balanced nuclear reaction
The fission of uranium-235 leads to the equation; 235/92U + 1 neutron → 92/36Kr + 141/56Ba + 3 neutrons + energy.
What is a fission reaction?The term fission reaction refers to the reaction in which a nucleus is bombarded with a particle which causes the nucleus to break down. This leads to the release of energy.
The fission of uranium-235 leads to the equation; 235/92U + 1 neutron → 92/36Kr + 141/56Ba + 3 neutrons + energy.
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How many moles of oxygen are required to make 4 moles of water?
Answer:
2 moles of oxygen
Explanation:
Basic Equation (given) :
2H₂ (g) + O₂ ⇒ 2H₂O (g)
From this, we understand for every 2 moles of water, 1 mole of oxygen is neededTaking the number of moles of oxygen and water in proportion :
1 : 21 × 2 : 2 × 22 : 4Therefore, 2 moles of oxygen are required to make 4 moles of water.
[tex] \textsf{\qquad\qquad\huge\underline{{\sf Answer}}} [/tex]
As per the given equation, we can infer that :
For getting 2 moles mole of water, 1 mole of oxygen gas was required. so to get 4 moles of water we need :
We just have to multiply the whole reaction by 2 on both sides, in order to get 4 moles of H2O on product side.
[tex] \qquad \qquad \rm4 \: H_2 + 2 \: O_2 \rightarrow4 \: H_2O[/tex]
therefore, we need
[tex]\qquad \sf \dashrightarrow \: 2 \times 1 = 2 \: moles \: \: oxygen \: gas[/tex]
Calculate the pressure (in kpa) of 1.5 mole of helium gas at 354 k when it occupies a volume of 16.5l.
Answer:
267.57 kPa
Explanation:
Ideal gas law:
PV = n RT R = 8.314462 L-kPa/K-mol
P (16.5) = 1.5 (8.314462)(354) P = 267.57 kPa
what type of rock is the Wave made of?
What type of rock is the wave made of?
Answer: The Wave is a natural formation of ~sandstone rocks~
V. What volume of nitric oxide will diffuse out of a porous partition in 10 seconds when 25 ml of methane diffuse out in 4 seconds?
The volume of nitric oxide that will diffuse out of the partition in 10 seconds when methane diffuses is 62.5 mL
What is rate of diffusion?This is defined as the amount diffused per unit time. Mathematically, it can be expressed as
Rate = volume / time
How to determine the rate of diffusion of methaneVolume of methane = 25 mLTime = 4 sRate = ?Rate = volume / time
Rate = 25 / 4
Rate = 6.25 mL/s
How to determine volume of nitric oxideTime = 10 sRate = 6.25 mL/sVolume of nitric oxide = ?Rate = volume / time
6.25 = volume of nitric oxide / 10
Cross multiply
Volume of nitric oxide = 6.25 × 10
Volume of nitric oxide = 62.5 mL
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Why do medical implants and prosthetics should be carefully designed when placed inside or on the surface of the body?
Answer:
because it needs to fit exactly into how your body is like
Explanation:
Solve and balance H2+Cl2
H2 + Cl2 → 2 HCl - Equation Balanced
Explanation:
Two elements H2and Cl2 combine to from a single compound, HCl. Hence, it is a combination reaction As two elements combine to from a compound, it is an element - element combination.
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In an ionic bond, metals lose electrons to become _____.
Answer:
In an ionic bond, metals lose electrons to become Cations.
Explanation:
Metal atoms lose electrons to form positive ions (cations).
Chemical labels must contain a product identifier, signal word and a pictogram to represent the hazards. what other information is required on a chemical label?
Answer:
The HCS now requires the following elements on labels of hazardous chemicals: Name, Address and Telephone Number of the chemical manufacturer, importer or other responsible party
Explanation:
I tried, I think this is the correct answer.
The concentration of reactants and products and the rate of reaction were measured during a chemical reaction. After the first 3 seconds, the rate of reaction was 1.8 x10−6 M/s. Which of the following would explain a lower rate after another 3 seconds?
The concentration of reactants increased while the concentration of product decreased.
The concentration of reactants decreased while the concentration of product increased.
All concentrations of reactants and products decreased.
All concentrations of reactants and products increased.
Lower rate after another 3 seconds of the given rate is concentration of reactants increased while the concentration of product decreased.
What is the rate of reaction?Rate of the reaction gives idea about the speed of the completion of the reaction or the formation of product.
Given rate of reaction = 1.8×10⁻⁶ m/sec
After 3 seconds rate of the reaction decreases, which means speed of the formation of product decreases as a result of which:
Concentration of product decreases.Concentration of reactant increases.Hence, concentration of reactants increased while the concentration of product decreased.
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Answer:
B. The concentration of reactants decreased while the concentration of product increased.
Explanation:
i took the test
Many factors would bring advantages when using fuel cells in cars, but which factor presents a drawback? fuel consumption hydrogen storage greenhouse gas emissions reliance on petroleum products
One potential drawback of using fuels cells in cars is that it require large tanks for hydrogen storage.
What are fuels cells?Fuel cells are cells which use hydrogen and oxygen as fuel to produce electrical energy for use in various purposes such as in powering cars.
The energy produced is as a result of redox reactions.
Fuels cells are clean renewable energy sources.
A potential drawback of using fuels cells in cars is that it require large tanks for hydrogen storage.
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how many moles of O2 will react with 0.6482 moles of H2O?
2C3H6O + 5O2 → 6CO + 6H2O
Answer:
n=0.648 moles
the ratio 5:6
x:0.648
x=0.54 moles
Atoms of arsenic (As) are often added to silicon (Si) in a process called doping to change the conductivity of the silicon. How does the addition of arsenic change the conductivity of silicon?
An atom of arsenic has one fewer valence electron and more electron shells than an atom of silicon, so the conductivity decreases because the arsenic atom gains an electron.
An atom of arsenic has one more valence electron and more electron shells than an atom of silicon, so the conductivity decreases because the arsenic atom loses the electron.
An atom of arsenic has one fewer valence electron and fewer electron shells than an atom of silicon, so the conductivity increases because the arsenic atom gains an electron.
An atom of arsenic has one more valence electron and more electron shells than an atom of silicon, so the conductivity increases because the arsenic atom loses the electron.
Answer:
B.) An atom of arsenic has one more valence electron and more electron shells than an atom of silicon, so the conductivity decreases because the arsenic atom loses the electron.
Explanation:
Silicon is located in the 3rd row and 14th column in the periodic table. Arsenic is located in the 4th row and 15th column in the periodic table. This means that arsenic has one more valence electron than silicon. Since arsenic is located one row down from silicon, its valence electrons occupy higher energy orbitals.
Silicon maintains a crystal-like lattice structure. Each silicon atom is covalently connected to assume this shape. When silicon gains one extra electron from arsenic, it experiences n-type doping. This new electron is not tightly bound in the lattice structure. This allows it to move more freely and conduct more electricity. This can also be explained using band gaps. Silicon, which previously had an empty conduction band, now has one electron in this band. This lowers the band gap between the conduction and valence bands and increases conductivity.
Answer:
its d
Explanation:
Which pair of molecules has hydrogen bonding interactions?.
Answer:
Hydrogen bonding is a special type of dipole-dipole interaction that occurs between the lone pair of a highly electronegative atom (typically N, O, or F) and the hydrogen atom in a N–H, O–H, or F–H bond.
A copper foil is made from copper, absolutely free of impurities. Which term or terms could be used to describe this sample of copper
Answer:
Explanation:
pure chemical substances and element.
All elements are pure. If this sample of copper had been impure, we would call it a mixture, not an element.
An unknown substance weighing 50.0g was heated from 36.0 to 69.0. In this process, the substance absorbed 5890.0J of energy. What is the specific heat of the substance
what is the percent yield
the percent yield: 9/21 x 100% = 42.9%
what is the law of Conservation of mass ?
Which reactions are spontaneous? i. c2h5oh(l) 3o2(g) right arrow. 2co2(g) 3h2o(l), delta.g = –36.7 kj ii. 2c6h6(l) 15o2(g) right arrow. 12co2(g) 6h2o(l), delta.g = –6,405 kj iii. caco3(s) right arrow. cao(s) co2(g), delta.g = 13.0 kj iv. ni(s) cl2(g) right arrow. nicl2(s), delta.g = 1,130.28 kj i and ii iii and iv i and iii ii and iv
Reactions I and II are spontaneous reactions since they have negative delta G values.
What are spontaneous reactions?Spontaneous reactions are reactions which proceed towards formation of products without addition of heat energy from the surroundings.
Spontaneous reactions have negative free energy change values (Delta G is negative) since the formation of products results in increase in entropy of the system.
Therefore, the spontaneous reactions are I and II because their delta G values are negative.
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Answer: A (I and II
Explanation:
At 0.500 atm and 15.0°C a sample of gas occupies 120. L. What volume does it occupy at
0.250 atm and 10.0°C?
O236 L
O 60 L
O 111 L
O 480 L
The combined gas law is used to determine the relationship between the pressure, temperature, and volume of the gas. The volume of the gas at 0.250 atm is 236 L. Thus, option A is correct.
What is combined gas law?The combined gas law uses the ideal gas equation to estimate the temperature, volume, or pressure of the given gas.
Given,
Initial pressure = 0.500 atm
Initial temperature = 288.15 K
Initial volume = 120 L
Final pressure = 0.250 atm
Final temperature = 283.15 K
The final volume is calculated as:
V₂ = (P₁V₁ T₂) ÷ (P₂ T₁)
= 0.500 × 120 × 283.15 ÷ 0.250 × 288.15
= 16989 ÷ 72.03
= 235.86 L
Therefore, 236 L is the final volume at 0.250 atm.
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An aluminum aerosol can will burst if the pressure inside reaches 210.0 psi. if the can initially contains an ideal gas at 459.5 kpa at 298.15 k, at what temperature (in k) will the can burst?
The can will burst at 938.45 K.
What is Gay Lussac's Law ?Gay Lussac's Law states that the pressure of a fixed amount of gas is directly proportional to the absolute temperature at constant volume.
i.e. P ∝ T
P= KT
P₁ = KT₁
P₂ = KT₂
Here we have considered that the gas is at two different temperatures and pressures which is denoted by T₁ , T₂ and P₁ , P₂
It can also be written as
(P₁ /P₂ ) = (T₁ / T₂)
It is given that
P₂ = 14.29 atm
P₁ = 4.535 atm
T₁ = 298.15 K
T₂ = ?
T₂ = (298.15 * 14.29 )/ 4.54
T₂ = 938.45 K
Therefore the can will burst at 938.45 K.
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A balloon containing 0.15mol of hydrogen gas (H2) has a volume of 0.75L. If the balloon is further inflated with additional hydrogen gas to a 3.75L volume, what is the total mass of hydrogen gas in grams in the balloon
The total mass of hydrogen gas in grams in the balloon given the data is 1.5 g
How to determine the new mole of hydrogenInitial mole (n₁) = 0.15 moleInitial volume (V₁) = 0.75 LNew volume (V₂) = 3.75 LNew mole (n₂) = ?The new mole of the gas can be obtained by using the ideal gas equation as follow:
PV = nRT
V / n = RT / P
RT / P = constant
V₁ / n₁ = V₂ / n₂
0.75 / 0.15 = 3.75 / n₂
5 = 3.75 / n₂
Cross multiply
5 × n₂ = 3.75
Divide both sides by 5
n₂ = 3.75 / 5
n₂ = 0.75 mole
How to determine the mass of hydrogenNumber of mole = 0.75 moleMolar mass of H₂ = 2 g/moleMass of H₂ = ?Mass = mole × molar mass
Mass of H₂ = 0.75 × 2
Mass of H₂ = 1.5 g
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What is the molarity of a solution that has 90 mol of solute dissolved in 6 liters of solvent? ___ M
Answer:
15M
Explanation:
To find molarity, you use the equation :
Molarity = [tex]\frac{moles of solute}{liters of a solution}[/tex]
So to find the molarity, you would do 90mols of the solute divided by 6 liters of the solvent which is 15M.
The energy that must be added to a system to break the bonds of the
reactants is known as _____?
potential energy
kinetic energy
thermal energy
activation energy
Answer:
activation energy
Explanation:
it is activation energy becauseThe activation energy for the forward reaction is the amount of
free energy that must be added to go from the energy level of the
reactants to the energy level of the transition state
A way of describing a chemical change that indicates what substances were present before the change and what substances are present after the change is called a _____.
A. chemical equation
B. chemical formula
C. chemical bond
D. All of the above
E. None of the above
Answer:
[tex]\\ \rm\dashrightarrow Chemical\: Equation [/tex]
Explanation:
When a chemical change happens or chemical reaction happens something yields at reactants and something at products
Representing them is called chemical equation
How many grams of NH4NO3 are required to produce 4.29 g of N2O?
Answer:
To produce 1 mole of N2O required 1 mole of NH4NO3 . Hence, 60 grams of NH4NO3 are required to produce 33.0 g N2O
Explanation:
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what are three different ways land is used as a resource
The lewis dot structure rule states that
s=n-a.
recall that s represents the.total
number of valence electrons needed for
all the atoms in a molecule to achieve an
octet.
what is s for silicon tetrachloride, sic14?
Answer:
32
Explanation:
The total valence electron is available for the Silicon tetrachloride
lewis structure is 32