Answer: Correct option is B)
The standard enthalpy change of formation of a compound is the enthalpy change which occurs when one mole of the compound is formed from its elements under standard conditions. The equation showing the standard enthalpy change of formation of water is
H
2
(g)+
2
1
O
2
(g)⟶H
2 ↑
O(l) 1 mole of water formed.
∴ Enthalpy of formation is −X2kJ/mol.
________________________________________________________
Explanation:I hope this helped
Give the name for the compounds below
Answer:
The R-O-R Chain
Explanation:
Please give me brainliest! Im so sorry if this is incorrect I really tried... -_- ;-;
A student diluted 10.0 milliliters (mL) of a 9.00 Molar (M) HCl solution in order to prepare a 0.50 M solution for his organic extraction analysis.What quantity of water, in mL, was added to make the 0.50M HCl solution?
A: 150
B: 160
C: 170
D: 180
The quantity of water in mL that was added to make the solution is 170 mL (option C)
How to determine the volume of the diluted solution Volume of stock solution (V₁) = 10 mL Molarity of stock solution (M₁) = 9 MMolarity of diluted solution (M₂) = 0.5 MVolume of diluted solution (V₂) =?M₁V₁ = M₂V₂
9 × 10 = 0.5 × V₂
90 = 0.5 × V₂
Divide both side by 0.5
V₂ = 90 / 0.5
V₂ = 180 mL
How to determine the volume of the water Volume of stock solution (V₁) = 10 mL Volume of diluted solution (V₂) = 180 mL Volume of water added =?Volume of water added = V₂ – V₁
Volume of water added = 180 – 10
Volume of water added = 170 mL
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What is one way that plants can harm the environment? Being a food source Blocking sunlight Giving off oxygen Providing shelter
Answer:
Your answer is B
Explanation:
carbon dioxide gas is not important for life. Do you agree or disagree?Explain your answer.
Answer:
Disagree carbon dioxide is one of the most important elements as it is present in nearly everywhere in our environment. We are also made from carbon. Carbon dioxide is present in our oceans. It is the most stable element in the periodic table therefore all element are compared to carbon-12 to calculate the relative mass of it from the element's isotopes. It is so important that a slight increase of CO2 production and other greenhouse gas production has the Earth become warmer causing it to have drastically impact our environment and also affecting our future.
In an ecosystem ,carbon dioxide is important so as to maintain the carbon foot prints.
What is an ecosystem?
Ecosystem is defined as a system which consists of all living organisms and the physical components with which the living beings interact. The abiotic and biotic components are linked to each other through nutrient cycles and flow of energy.
Energy enters the system through the process of photosynthesis .Animals play an important role in transfer of energy as they feed on each other.As a result of this transfer of matter and energy takes place through the system .Living organisms also influence the quantity of biomass present.By decomposition of dead plants and animals by microbes nutrients are released back in to the soil.
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Atoms with outer shells that are only partially filled are the most stable.
True
False
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falseAtoms are most stable when their outer shells are fulfilled or half-filled.[tex]\sf{\:мѕнαcкεя\: ♪...}[/tex]
what is the chemical formula for flourine?
Answer:
H2(g) + F2(g) ----> 2HF(g)
Answer = F2
Show how you would convert 3-cyclopentylbutanal to a carboxylic acid.
Conversion of 3-cyclopentylbutanal to a carboxylic acid will be made possible through oxidation.
What is Oxidation?This is the process in a chemical reaction which involves the gain of oxygen atoms.
3-cyclopentyl butanal is oxidized to carboxylic acids using potassium dichromate(VI) solution which turns green in the presence of dilute sulfuric acid.
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If 3.00 moles of FeCl3 are dissolved in water to make 5.00 L of solution, what is the molarity of the solution?
Answer:
M = [tex]\frac{3}{5}[/tex] or 0.60 M
Explanation:
Data:
Moles = 3.00 molLiters = 5.00 LWanted:
MolarityEquation:
M = [tex]\frac{mol}{L}[/tex]Solution:
M = [tex]\frac{3.00 mol}{5.00 L}[/tex]M = [tex]\frac{3}{5}[/tex] or 0.60 MNote:
The answer is not in a correct significant figure.
What are some characteristics of Nonmetals?
Answer:
Insulators
Explanation:
They could work as Insulators
Hope it Helps
Based on the differences in electronegativities, with which atom is francium (Fr) most likely to form an ionic bond?
A. Fr-Cl = 2.46
B. Fr-Se =1.76
C. Fr- At = 1.50
D. Fr-l =1.96
An ionic bond will be most likely formed between francium and chlorine having an electronegativity difference of 2.46.
What is is an ionic bond?An ionic bond is formed between to atoms that have a high difference in electronegativity between them. We now have to look out for the atoms that have a very high electronegativity difference. That pair is most likely to form an ionic bond.
Hence, an ionic bond will be most likely formed between francium and chlorine having an electronegativity difference of 2.46.
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What is the correct formula for dinitrogen hexafluoride?
Answer:
The correct formula for dinitrogen hexafluoride is Memorize the prefixes for number of atoms, Write the chemical symbol for the first element, add the number of atoms present as a subscript, Write the chemical symbol for the second element, Add the number of atoms present as a subscript, Practice with some examples.
Explanation:
1: Memorize the prefixes for number of atoms. In naming compounds, Greek prefixes are used to indicate the number of atoms present for each element. Covalent compounds are written out as molecular formulas due to the fact that each compound is a distinct, separate molecule.[1] Covalent compounds have the first element written out completely while the second element is named with the suffix "ide." For example, diphosphorus trisulfide has a chemical formula of P2S3. Below are the prefixes for 1-10:
1: Mono-
2: Di-
3: Tri-
4: Tetra-
5: Penta-
6: Hexa-
7: Hepta-
8: Octa-
9: Nona-
10: Deca-
2: Write the chemical symbol for the first element. When a compound has been written out, you must identify the elements and know their chemical symbols. The first element written is "first name" of the compound. Use the periodic table to find the chemical symbol for the element. For example: Dinitrogen hexafluoride. The first element is nitrogen and the chemical symbol for nitrogen is N.
3: Add the number of atoms as a subscript. To identify the number of atoms present for each element, you simply need to look at the prefix of the element. Memorizing the Greek prefixes will help you to be able to write chemical formulas quickly without looking anything up. For example: Dinitrogen has a the prefix "di-" which means 2; therefore, there are 2 atoms of nitrogen present. Write dinitrogen as N2.
4: Write the chemical symbol for the second element. The second element is the "last name" of the compound and will follow the first element. For covalent compounds, the element name will have a suffix of "-ide" instead of the normal ending of the element. For example: Dinitrogen hexafluoride. The second element is fluorine. Simply replace the "ide" ending with the actual element name. The chemical symbol for fluorine is F.
5: Add the number of atoms present as a subscript. As you did with the first element, identify the number of atoms present in the second element by reading the prefix. Using this prefix, write the number of atoms as a subscript to the right of the chemical symbol. For example: Hexafluoride has a prefix of "hexa-" which means 6; therefore, there are 6 atoms of fluorine present. Write hexafluoride as F6. The final chemical formula for dinitrogen hexafluoride is N2F6.
6: Practice with some examples. When first learning chemistry, there is a lot of memorization involved. It is kind of like learning a new language. The more examples you practice with, the easier it will be to decipher chemical formulas in the future and learn the language of chemistry. Sulfur dioxide: SO2 Carbon tetrabromide: CBr4 Diphosphorus pentoxide: P2O5
A typical car engine produces 44,000 kJ of heat in an hour. The cooling system has a capacity of 8.40 L and is filled with a 50:50 mixture of anti-freeze (specific heat capacity of 8.37 J/g-oC, density of 1.038 g/mL). In maintaining a constant engine temperature, the cooling system temperature increased from 95oC to 110oC. (Assume this is within allowable limits.) How many times did the cooling system turn over its volume of anti-freeze to maintain the engine temperature during its hour of operation? Show your work. (Assume that only the cooling system removes heat from the engine and no other mechanism of heat removal is involved.)
Answer:
"The Circuit" by author Francisco Jimenez, tells the story of Panchito and his experiences on a new country, having to deal with learning a second language and adapting to a new culture and environment. Even if you had not been in a similar situation as Panchito, you could connect his stories to your personal experiences at school in many ways. Maybe, the first classes of spanish or french were difficult to you as you could not understand all the words the teacher was saying, but as you were learning things were easier for you. Or you can connect Panchito's experiences by writing about that time in school you were not afraid of asking for help when you had to deal with a difficult situation
Antifreeze is the coolant used in car engines that regulates the temperature. The cooling system turns over around 40 times to regulate the temperature.
What is heat?Heat is the product of the mass, temperature change, and the specific heat of the substance.
Given,
The heat of surroundings = 44000 kJ
Mass of the substance = 8719 gm
Specific heat = 8.37 J/g degrees celsius
Change in temperature = 15 degrees celsius
Q system is calculated as:
8719 × 8.37 × 15
= 1095 kJ
The number of antifreeze is calculated as:
Δ H ÷ Q system = 44000 ÷ 1095
= 40
Therefore, 40 times the cooling system was turned over.
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How much energy is needed to completely boil a 5.05g sample of water?
The energy required to completely boil a 5.05 g-sample of liquid water at its boiling point is 2.73 kcal.
What is boiling?Boiling is the process in which, upon absorbing energy in the form of heat, a substance goes from the liquid state to the gaseous state.
We have a 5.05 g-sample of liquid water. We can calculate the heat required to completely boil it using the following expression.
Q = ΔH°vap × m
Q = 0.540 kcal/g × 5.05 g = 2.73 kcal
where,
Q is the heat absorbed.ΔH°vap is the enthalpy of vaporization.m is the mass.The energy required to completely boil a 5.05 g-sample of liquid water at its boiling point is 2.73 kcal.
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A gas containing 80% CH4 and 20% He is sent through a quart/ diffusion tube (see Figure P8.8) to recover the helium, Twenty percent by weight of the original gas is recovered, and its composition is 50% He. Calculate the composition of the waste gas if 100 kg moles of gas are processed per minute.
For a gas containing 80% CH4 and 20% He is sent through a quart diffusion tube, the composition is mathematically given as
%He=12.5%
%CH4=87.5%
What is the composition of the waste gas if 100 kg moles of gas are processed per minute?Generally, the equation for the Material balance is mathematically given as
F=R+W
Therefore
100=0.20*1000+W
W=80kmol/min
In conclusion, waste gas compose
2.0/100*100=50/100*20+%*80
Hence
%He=12.5%
%CH4=87.5%
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Carbonates are typically insoluble, but one exception would be a carbonate containing what kind of cation? a) ammonium b) a transition metal c) a group two metal lead
For a carbonate containing a kind of cation, we have that Option 1 is the correct answer: ammonium.
What are Carbonates?Generally, Any of two families of chemical substances generated from carbonic acid or carbon dioxide is referred to as carbonate.
In conclusion, Sodium, potassium, and ammonium are the three carbonates that are soluble.
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How many moles of Cu2S are produced when 6.1 moles of Cu is reacted w
excess S?
Cu +S - Cu2S
When 6.1 moles of Cu is reacted with excess S 3.05 number of mole of Cu2S are produced.
Calculation of number of moles of a moleculeThe balance equation of the above reaction is:
2Cu +S --> Cu2S
This means that 2 moles of Cu = 1 mole of Cu2S
Therefore 6.1 moles of Cu = X mole of Cu2S
Make X the subject of formula,
X = 6.1 ×1/2
X = 3.05 moles
Therefore, when 6.1 moles of Cu is reacted with excess S 3.05 number of mole of Cu2S are produced.
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25 POINTS
Part C
Record what you observe in these images showing the banks of the Dead Sea.
One of the most significant characteristics of the Dead Sea is its salinity level. The images show the rock salt deposits on the shore.
What are the characteristics of the characteristics of the Dead sea?
Location
The dead dea is the most salty landlocked lake on the Earth surface. It is located in the middle East, between Israel and Jordania. Its nort-south length is about 80 km and its east-west wide varies between 7 and 20 km.
AfluentThe Jordan river is the most significan afluent on the Dead Sea, from which it receives most of its water.
Water levelThe Dead Sea is the deepest and lowest water body on the Earth, being its surface level 400 mt below the sea level.
Due to different reasons, during the last decades, there was a sharp and continuous drop in the water level. For this reason the lake surface is decreasing year after year.
SalinityAmong its many characteristics, one of them -and probably the most notorious one- is the salinity. The percentage of dissolved salts in the lake is much higher than the one recorded in the oceans, seas or lakes of the globe. Its value is between 8 and 10 times higher the salt level of oceans.
The salts present in the lake are chlorine, magnesium, sodium, calcium, potassium, bromine and sulfur. Their concentration vary according to the strate and deph, but it tends to increase toward the lake’s bottom. The high salinity level provides an oily aspect, bleach taste, and extreme density.
Several rock salt deposits can be seen on the shore and near it. Salt columns can also be seen in deepest areas. These structures are becomming more common with time, as water evaporates, water provision from afluent sources decreases, and salinity near the surface increases.
Forms of lifeMainly due to the extreme salt level, which turns to be lethal, almost no forms of life inhabit these waters. Only some bacteria species and one algae species can be found in the water, and some plant species near the coasts.
What we can observe in these images are the rock salt deposits on the shore.
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How much nuclear fuel produces as much energy as 2 to 3 million kilograms of coal?
1 thousand kilograms
1 million kilograms
1 kilogram
10 kilograms
Answer:
1 kilogram of nuclear fuel
Explanation:
Answer:
1 Kilogram.
Explanation:
I took the test and I got an A. Really hope this helps you, friend!
HELP!!! WILL MARK BRAINLIEST!!
The diagram below shows different positions of Earth and Mars around the sun.
Based on the diagram, which of these statements is correct?
Earth covers different areas in the same amount of time at position A and position B.
Earth covers a greater area in position A than in position B in the same amount of time.
Mars covers a greater area in position A than in position B in the same amount of time.
Mars covers the same area in the same amount of time at position A and position B.
Answer:
Earth covers a greater area in position A than in position B in the same amount of time.
Explanation:
Based on the diagram that shows different positions of Earth and Mars around the sun, it seems that this statement is correct:
Earth covers a greater area in position A than in position B in the same amount of time. (Covers as I understood it means "overshadowing" Mars)
Question 9 of 30
The average atomic mass of boron is 10.81 amu. Based on the atomic
masses of the two isotopes of boron, how do the relative abundances of the
isotopes compare?
Isotope
Atomic mass (amu)
B-10
10.013
B-11
11.009
O A. B-11 is almost twice as abundant as B-10.
B. B-10 and B-11 are equally abundant.
O C. B-10 is twice as abundant as B-11.
D. B-11 is more than twice as abundant as B-10.
Answer: D
Explanation:
Based on the atomic masses of the two isotopes of boron, B-11 is more than twice as abundant as B-10. The correct option is option D.
What is relative abundance?The reason why some isotopes have a greater prevalence naturally common on Earth then others has something to do with the simple fact that various isotopes have varying relative abundances.
The proportion of a given isotope with a particular atomic mass that exists in nature is known as its relative abundance. Isotopes are different chemical elements that differ in nucleon number and neutron number, respectively. The average atomic mass of boron is 10.81 amu. Based on the atomic masses of the two isotopes of boron, B-11 is more than twice as abundant as B-10.
Therefore, B-11 is more than twice as abundant as B-10. The correct option is option D.
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A tank of bromine gas is initially at a pressure of 5.6 atm, a temperature of 67°C, and has a volume of 97 L. The tank is expanded to 100 L and has a new pressure of 8 atm.
What is the new temperature of the gas in Kelvin?
The new temperature of the bromine gas as the tank is expanded to the given volume and pressure is 500.96 Kelvin.
Combined gas lawCombined gas law put together both Boyle's Law, Charles's Law, and Gay-Lussac's Law. It states that "the ratio of the product of volume and pressure and the absolute temperature of a gas is equal to a constant.
It is expressed as;
P₁V₁/T₁ = P₂V₂/T₂
Given the data in the question;
Initial volume V₁ = 97LInitial pressure P₁ = 5.6atmInitial temperature T₁ = 67°C = 340.15KFinal volume V₂ = 100LFinal pressure P₂ = 8.0atmFinal temperature T₂ = ?To calculate the new temperature the gas, we subtsitute our given values into the expression above.
P₁V₁/T₁ = P₂V₂/T₂
P₁V₁T₂ = P₂V₂T₁
T₂ = P₂V₂T₁/P₁V₁
T₂ = ( 8.0atm × 100L × 340.15K ) / ( 5.6atm × 97L )
T₂ = 272120LatmK / 543.2Latm
T₂ = 500.96K
Therefore, the new temperature of the bromine gas as the tank is expanded to the given volume and pressure is 500.96 Kelvin.
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4. What energy transformation takes place when you light a match?
electromagnetio to potential
b. chemical to nuclear
O. mechanical to thermal
d. sound to eleotrioal
Mechanical Energy to Thermal Energy
hope it helps...!!!
Two identical automobiles are racing towards each other. One vehicle is going 30 mph, the other is going 60 mph. What will happen when the two vehicles collide, and why? What would happen if the two cars were moving at identical speeds?
When the two vehicles collide, then vehicle with slow speed will pushes back.
How we define speed?Speed of any moving body is define as the distance travelled by that body in per unit of time.
As it is mentioned that one car has a speed of 30 mph and another one has a speed of 60mph, if both of these cars get collide then the car with high speed pushed back the car with low speed.
Hence the car with slow speed pushed back.
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Suppose that the pressure of 1.00L of gas is 500mmHg when
the temperature is 200K. At what temperature is the Volume 2.00L
and the pressure 0.750 atm?
Answer:
456 K
Explanation:
PV = nRT
PV/ T = nR since nR is constant for this scenario
P1 V1 /T1 = P2 V2 / T2
500 * 1 / 200 = (760*.75) *2 /T2 Solve for T2 =456 K
(Note that .750 atm = 760 mmHg * .75 )
how many Aluminum atoms are in Al2O3
a. 3
b. 2
c. 5
d. 1
Given the data from the question, the number of aluminum atoms in aluminum oxide, Al₂O₃ is 2 (Option B)
Composition of aluminum oxide, Al₂O₃From the formula of the compound, Al₂O₃ we see that the compound is composed of
Aluminum Oxygen How to determine the number of aluminum atoms Formula of compound = Al₂O₃Number of oxygen atoms j= 3 × 1 = 3Number of aluminum atoms = 2 × 1 = 2From the above, we can conclude that Al₂O₃ contains 2 atoms of aluminum.
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PLEASE HELP!!!
Using the rules that you learned during the session, what is the answer to the following question?
55.78 * 23.7
Answers
1,321.986
1,321.99
1,322
1,320
Answer:
(d) 1,320
Explanation:
You want the product 55.78 × 23.7 rounded appropriately.
Significant figuresWhen a number has both an integer part and a decimal fraction, all of the digits are significant. Here, that means the first number has 4 significant figures, and the second number has 3 significant figures.
The number of significant figures in a product or quotient will be the least of the numbers of significant figures of the contributors. Here, the product can only have 3 significant figures.
55.78 × 23.7 = 1321.986 ≈ 1320 . . . . rounded to 3 sf
Using the rules for significant figures, the answer is 1320.
__
Additional comment
Generally, the rules for significant figures apply to quantities derived from measurements. They can also be applied to estimates, where the result of computation using numbers of different precision cannot have any more accuracy than the least precise contributor.
The other useful rule in this process is that the rounding is saved for the final answer. Intermediate results should be carried to the full precision available.
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I need help finding arm
Answer:
line 15 is were you can find the a then you look around for the r but as a heads up the m thats supposed to be there was actually inverted into a w in theory it must have been misprinted.
Explanation:
why is it difficult for non metals to form positive ions
Answer:
Because the non-metal comes from the right hand side of the Periodic Table as we face it, its nuclear charge is very poorly shielded by its INCOMPLETE valence electronic shell, and this results in the well-known contraction of atomic radii across the Table from left to right.
Explanation:
Non metals usually gain electrons so they have more electron in the shells than protons in nucleus and hence they form negative ions. However, metals usually lose electron so they have more protons in nucleus than electrons in shells and hence they form positive ions.
A liquid has a mass of 3.35 g and volume of 5 mL. What is its density?*
D =
mass
volume
Explanation:
density= mass × volume
3.35×5
=. 16 .75
Part 1
Titrant (NaOH) concentration: 0.1 m NaOH
Vinegar volume: 2.0 mL vinegar
Initial buret reading (initial NaOH volume): 0.0 mL
Final buret reading (final NaOH volume): 17.7 mL
Calculate the moles of NaOH using the volume and molarity of NaOH.
Show your
work. moles = molarity. volume (in Liters).
1.77 moles
17.7 moles
0.177 moles
0.00177 moles
Part 2
The moles of NaOH used in the titration would be 0.00177 moles while the molarity of the vinegar will be 0.885 M
Titration calculationRecall that: mole = molarity x volume
In this case, the molarity of the NaOH= 0.1 M
Volume of NaOH = 17.7 - 0.0 = 17.7 mL
Mole of NaOH used = 0.1 x 17.7/1000 = 0.00177 moles.
Since NaOH and vinegar have 1:1 mole ratio, the mole of vinegar will also be 0.00177 moles.
Molarity of vinegar = mole/volume = 0.00177/0.002 = 0.885 M
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