Answer:
. a pure substance consists only of one element or one compound.
. a mixture consists of two or more different substances, not chemically joined together
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:
What is the formula for calculating the change in thermal energy?
Answer: :Change in thermal energy = mass x specific heat capacity x change in temperature.
Explanation: what it basically means is mass x heat x the change in temperature.
Why do fireworks produce heat when they explode?
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
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.
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]
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~
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 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
Which equation represents a combustion reaction?
1) 4fe + 3o2 = 2fe2o3
2) 2h2o = 2h2+o2
3) 2agno3 + h2s = ag2s + 2nho3
4) 2al + n2= 2aln
Answer:
2
Explanation:
do take note that combustion reactions releases oxygen.
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.
I hope it'll help you...
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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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
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:
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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witchh organsim primary cosumers
Answer:
Primary consumers are herbivores, feeding on plants
Explanation:
:)
Primary consumers are at the second trophic level of the food pyramid. This means that they eat producers. An example of a primary consumer would be a grasshopper eating grass. Primary consumers get eaten by secondary consumers, such as a rabbit who eats grass, and the rabbit gets eaten by a fox.
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).
what is the percent yield
the percent yield: 9/21 x 100% = 42.9%
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
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:
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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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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what are three different ways land is used as a resource
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.
A mole is known by what other name?
Answer: avogadros number/constant
Explanation:
Which of the following is not a type of energy
A. Heat from an oven.
B. Electricity in a power cord.
C. Light from a lightbulb.
D. Smoke from a fire.
Answer:
smoke from a fire Is not an example of energy
Define density please thanks!!
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.
What was in Flint's water that caused 12 people to die?(1 point)
lead
total triahalomethanes
Legionella pneumophila
Escherichia coli
The presence of lead in Flint's water is what caused the death of 12 people.
Option A.
What was in Flint's water?The Flint water crisis started in 2014 when the city of Flint, Michigan, switched its water source from Lake Huron to the Flint River as a cost-cutting measure.
The water from the Flint River was more corrosive and caused lead to leach from the pipes, contaminating the drinking water. This led to high levels of lead in the drinking water, which is a potent neurotoxin that can cause a variety of health problems, particularly in children.
The contamination also led to an outbreak of Legionnaires' disease, a severe form of pneumonia, which was linked to at least 12 deaths in the area.
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