The statement that should be rightly mentioned with respect to the equation of thermochemical is 4 Fe (s) + 3O2(g) -------> 2Fe2O3(s) ΔH = -3926 KJ
What is the thermochemical equation?It is a balanced of stoichiometric chemical equation that involved the change with respect to enthalpy, ΔH. Here the reactants and the product state should be considered as the liquid, solid, or in gaseous state.
Also, the value of the heat should be absorbed since ΔH < 0 so the reaction should be considered as the exothermic and ΔH > 0 then the reaction is endothermic.
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The correct thermochemical equation is '4Fe (s) + 3O2 (g) → 2Fe2O3 (s), ΔH = −3,926 kJ', which includes the balanced chemical equation and the enthalpy change for the whole reaction.
Explanation:The question asks which statement is a correctly written thermochemical equation. A proper thermochemical equation includes the balanced chemical equation alongside the enthalpy change (ΔH) for the reaction. The enthalpy change represents the heat absorbed or released during the reaction when it occurs at constant pressure. There is only one correct thermochemical equation provided:
4Fe (s) + 3O2 (g) → 2Fe2O3 (s), ΔH = −3,926 kJ
This equation is balanced and represents the reaction of iron (Fe) with oxygen (O2) to form iron(III) oxide (Fe2O3). The enthalpy change is given for the entire reaction, not per mole, which is the correct way to represent it in a thermochemical equation. The other equations either do not include the enthalpy change in the correct units or are missing it entirely.
How many grams of oxygen gas are there in a 2.3L tank at 7.5 atm and 24° C?
Answer:
22.656 grams of oxygen gas are there in a 2.3L tank at 7.5 atm and 24° C
Explanation:
An ideal gas is characterized by three state variables: absolute pressure (P), volume (V), and absolute temperature (T). The relationship between them constitutes the ideal gas law:
P * V = n * R * T
where R is the molar constant of the gases and n the number of moles.
In this case you know:
P= 7.5 atmV= 2.3 Ln= ?R= 0.082 [tex]\frac{atm*L}{mol*K}[/tex]T= 24 °C= 297 °K (being 0°C=273°K)Replacing:
[tex]7.5 atm* 2.3 L=n*0.082 \frac{atm*L}{mol*K} *297K[/tex]
Solving:
[tex]n=\frac{7.5 atm* 2.3 L}{0.082 \frac{atm*L}{mol*K} *297K}[/tex]
n=0.708 moles
Knowing that oxygen gas is a diatomic gas of molecular form O₂ and its mass is 32 g / mole, you can apply the following rule of three: if 1 mole contains 32 grams, 0.708 moles, how much mass will it have?
[tex]mass=\frac{0.708 moles*32 grams}{1mole}[/tex]
mass= 22.656 grams
22.656 grams of oxygen gas are there in a 2.3L tank at 7.5 atm and 24° C
Answer:
The mass of oxygen gas is 22.66 grams
Explanation:
Step 1: Data given
Volume of tank = 2.3 L
Pressure = 7.5 atm
Temperature = 24.0°C = 273 +24 = 297 K
Step 2: Calculate moles oxygen gas
p*V = n*R*T
⇒with p = the pressure of the oxygen gas = 7.5 atm
⇒with V = the volume of the tank : 2.3 L
⇒with n = the moles of oxygen gas = TO BE DETERMINED
⇒with R = the gas constant = 0.08206L*atm/mol*K
⇒with T = the temperature = 297 K
n = (p*V- / (R*T)
n = (7.5 atm * 2.3L) / (0.08206 L*atm/mol*L * 297K)
n = 0.708 moles
Step 3: Calculate mass of oxygen gas
Mass O2 = moles O2 = molar mass O2
Moles O2 = 0.708 moles * 32.0 g/mol
Moles O2 = 22.66 grams
The mass of oxygen gas is 22.66 grams
If the pressure changes from 1 atm to 3 atm, what does the volume of 30 L change to
Answer: 10L
Explanation:
Given that:
Initial pressure P1 = 1 atm
New pressure P2 = 3 atm
Initial volume V2 = 30 L
New volume V2 = ?
Since pressure and volume are involved, apply the formula for Boyle's law
P1V1 = P2V2
1 atm x 30L = 3 atm x V2
30 atm L = 3 atm x V2
V2 = (30 atm L / 3 atm)
V2 = 10L
Thus, volume changed to 10 liters
According to the chart, which substance has the lowest OH' concentration?
A)
urine
lemon juice
tomato juice
D)
black coffee
Answer:
lemon juice
Explanation:OH is in bases and lemon juice is an acid
Which term identifies a factor that will shift a chemical equilibrium?
Answer:
Temperature
Explanation:
Temperature is identified as a factor which will result in a shift in the chemical equilibrium.
What is Chemical equilibrium?This is defined as the point in which the concentrations of reactants and products remain constant with time.
Temperature could result in shifting the equilibrium to the left or right depending on factors such as nature of reactant etc.
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If a dolphin is producing a vocalization with a frequency of 35 Hz, traveling at 1470 m/s, what is the wavelength of the sound?
Answer:
42
Explanation:
Divide the distance by the time.
If a dolphin is producing a vocalization with a frequency of 35 Hz, traveling at 1470 m/s, then wavelength of sound is 42m.
How do we calculate wavelength?Wavelength of sound will be calculated by using the below formula as:
λ = υ / f, where
υ = velocity or speed of sound = 1470 m/s
f = frequency of wavelength = 35 Hz
On putting values we get
λ = 1470 / 35 = 42m
Hence resultant wavelength of sound is 42m.
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Megan prepares a pitcher of lemonade by adding a quarter cup of granular sugar to the mixture. Which action should she take so the sugar dissolves in the lemonade faster?
A) Increase the amount of sugar.
B) Add a small amount of powdered sugar.
C) Stir the water continuously.
D) Cool the pitcher.
E) Reduce the original quantity of water.
ANSWER: C - Stir the water continuously ;)
Answer:
C. Stir the water continuously
Explanation:
stirring allows the solvent to continuously stick to the solvant
What temperature would 3.54 moles of xenon gas need to reach to exert a pressure of 1.57 atm at a volume of 34.6 l
Answer:
186.9Kelvin
Explanation:
The ideal gas law equation is PV = n R T
where
P is the pressure of the gas
V is the volume it occupies
n is the number of moles of gas present in the sample
R is the universal gas constant, equal to 0.0821 atm L /mol K
T is the absolute temperature of the gas
Ensure units of the volume, pressure, and temperature of the gas correspond to R ( the universal gas constant, equal to 0.0821 atm L /mol K )
n = 3.54moles
P= 1.57
V= 34.6
T=?
PV = n R T
PV/nR = T
1.57 x 34.6/3.54 x 0.0821
54.322/0.290634= 186.908620464= T
186.9Kelvin ( approximately to 1 decimal place)
Sample Response: Jade's error occurs in the top-right square of the Punnett square. In this square, she identifies the phenotype as freckles, but to have freckles, the offspring must have at least one dominant allele. The offspring in this box are ff. Because there is no dominant allele present, the offspring will not have freckles.
What did you include in your response? Check all that apply.
Jade’s error occurs in the top-right square of the Punnett square.
Jade identifies the phenotype as freckles.
To have freckles, the offspring must have at least one dominant allele.
The offspring in this box are ff.
There is no dominant allele present, so the offspring will not have freckles.
Answer:
all of them
Explanation:
Answer:
1,2,3,4,5
Explanation:
plz brainlest me
The reaction 2NO (g) → N2 (g) + O2 (g) has a ΔH =−180.5 kJ .
How much heat will be required to produce 44.8 L of NO by the reverse reaction?
180.5 kJ
301 kJ
322.3 kJ
644 kJ
Answer: the answer is 180.5 i am 100% i just did the test
The heat that should be required to produce 44.8 L of NO by the reverse reaction is 180.5 J.
What is heat?The heat energy should be converted from one body to the another due to which there should be the difference in the temperature. In the case when two bodies should be at the different temperature so here the energy should be transferred i.e. the heat should be flows i.e from the hotter body to the colder.
hence, The heat that should be required to produce 44.8 L of NO by the reverse reaction is 180.5 J.
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According to the law of conservation of momentum, which statement is true
about a system that has no external forces acting on it?
O
A. An increase in momentum before a collision must equal an
increase in momentum after the collision.
O
B. The sum of the momentums of all objects in the system is always
zero.
C. The total momentum of all objects in the system does not change.
D. The momentum of each object in the system remains the same
before and after a collision.
Answer:
D. The momentum of each object in the system remains the same
before and after a collision.
Explanation:
The law of conservation of momentum states that the momentum in a closed system does not change unless there is an outside force influencing the closed system.
Oceanic crust is
-
made mostly of granite
made mostly of limestone and salt
thinner than continental crust
thicker than continental crust
Answer:
It is thinner than the continental crust.
Explanation:
The oceanic crust is largely made up of basalt, a dense type of rock that forms from solidified lava, and it is thinner than the continental crust that is mainly composed of granite.
Explanation:The oceanic crust is primarily composed of a type of rock known as basalt. This is a dark, dense igneous rock that forms due to the cooling and solidifying of lava. In contrast to the granitic composition of the continental crust, the oceanic crust's basaltic composition is denser but thinner than the continental crust. Hence, the oceanic crust is not made mostly of granite, limestone or salt, but rather, it is predominantly basalt and it is not thicker but thinner than continental crust.
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1. What is a physical change?
(10 Points)
O
A. A new substance is formed.
O
B. A substance is altered in size, shape or form.
O
C. Something has to break.
O
D. Something has to be folded.
What aboaieloben
Answer B
Explanation:
A Physical change is a change in one or more physical properties of matter without any change in chemical properties. For example physical change include changes in the size shape of matter.
An enthusiastic car owner checks his tire pressure religiously and makes note that his tire pressure is 220 kPa in 80 degrees Fahrenheit (26.7 degrees Celsius). A strong cold front comes in and later in the week the temperature has dropped to 36 degrees Fahrenheit (2.2 degrees celsius). How can the car owner use gas laws to calculate the new tire pressure (in kPA units)?
Answer:
202 KPa
Explanation:
Step 1:
Data obtained from the question.
Initial Pressure (P1) = 220 kPa
Initial temperature (T1) = 26.7°C
Final temperature (T2) = 2.2°C
Final pressure (P2) =?
Step 2:
Conversion of the Celsius temperature to Kelvin temperature.
Temperature (Kelvin) = temperature (celsius) + 273
T1 = 26.7°C + 273 = 299.7 K
T2 = 2.2°C = 2.2°C + 273 = 275.2 K
Step 3:
Determination of the new pressure.
The new pressure of the tire can be obtained as follow:
P1/T1 = P2/T2
220/299.7 = P2/275.2
Cross multiply to express in linear form
299.7 x P2 = 220 x 275.2
Divide both side by 299.7
P2 = (220 x 275.2)/299.7
P2 = 202 KPa
Therefore, the new pressure of the tire is 202 KPa
When the temperature drops to 2.2 degrees Celsius, the tire pressure will decrease to approximately 202.1 kPa.
We can use the combined gas law which is derived from the ideal gas law. The combined gas law relates pressure, volume, and temperature without needing to know the quantity of gas, and is expressed as (P₁/T₁) = (P₂/T₂), where P₁ and T₁ are the initial pressure and temperature, and P₂ and T₂ are the final pressure and temperature.
To do so, we first convert temperatures to Kelvin by adding 273.15. Then we rearrange the formula to solve for P₂:
P₂ = P₁ x (T₂/T₁)P₂ = 220 kPa x (275.35 K / 299.85 K)P₂ = 202.1 kPaTherefore, the tire pressure will decrease to approximately 202.1 kPa.
Ice melts to form water. And water freezes to form ice. Choose the TRUE statement about these changes.
A. Both melting and freezing are physical changes.
B. Both melting and freezing are chemical changes.
C. Melting is a physical change while freezing is a chemical change.
D. Melting is a chemical change while freezing is a physical change.
Answer:
A. Both freezing and melting are physical changes.
Explanation:
Even if you were to freeze water, the molecules are still water molecules, and vise versa with melting it.
Answer: Option A) Both melting and freezing are physical changes.
Explanation:
A physical change is one which is easily reversible and in which no new substances are formed.
Hence, since ice melts to form water (melting), and water freezes to form ice back (freezing), both melting and freezing are easily reversible and do not form new products.
Thus, both melting and freezing are physical changes.
What net ionic equation describes the reaction that occurs when AI2(SO4)3(aq)andNa3PO4(aq)are mixed together?
Answer: chemical reaction
Explanation:
Al3+(aq)+PO4^3-(aq)+3SO4^2-(aq0 --> 3AlPO4(s)+3Na+(aq)
If the Dry bulb reads 25 degrees Celsius and the wet bulb reads 22
degrees Celsius. Is the relative humidity high or low? How do you know?
Answer:
Relative humidity is low .
Explanation:
The wet bulb reads low temperature because due to low humidity of atmosphere , evaporation of water takes place from the wet bulb which makes the bulb cool and therefore it reads lower temperature . In the process of evaporation , heat equal to latent heat of vaporization is taken from the bulb and it loses temperature.
PLEASE HELP!CHEMISTRY QUESTION
On Venus the atmospheric pressure is 2700 mmHg and nitrogen gas makes up 3.0 % of the atmosphere. What is the partial pressure of nitrogen on Venus? mmHG
Answer: The partial pressure of nitrogen on Venus is 81 mmHg
Explanation:
To calculate the partial pressure of the gas, we use the equation given by Raoult's law, which is:
[tex]p_{A}=p_T\times \chi_{A}[/tex]
where,
[tex]p_A[/tex] = partial pressure of nitrogen gas = ?
[tex]p_T[/tex] = total pressure = 2700 mmHg
[tex]\chi_A[/tex] = mole fraction of nitrogen gas = 3.0 % = 0.03
Putting values in above equation, we get:
[tex]p_{N_2}=2700mmHg\times 0.03\\\\p_{N_2}=81mmHg[/tex]
Hence, the partial pressure of nitrogen on Venus is 81 mmHg
20 pts :p will mark brainliest too.
I = Increase.
D = Decrease.
With the grass it'll decrease because more rabbits means more grass being eaten. With the animals the more rabbits there are the more food there is for them which means they more they can feed children and keep repopulating. And halving the rabbit population would be opposite I'd assume.
Even though the neighborhood shown by the green star was not next to any of these fires, how was the neighborhood affected by them?
A)
The heat generated by these fires made the temperatures in the surrounding areas increase.
B)
The smoke produced by these fires were carried by strong winds and made the air hard to breathe.
C)
The chemicals that were released by these fires cleared out the air and improved overall visibility.
D)
The air around the neighborhood was cooled due to the fire sucking the heat out of the surrounding air.
Answer:
B
Explanation:
B is the only possible answer that makes much sence, smoke is very toxic and it makes it hard to breath and is bad for your lungs
If the temperature of a gas changes, but the number of moles and volume remain constant, which of the following values must also change?
Density
Pressure
Number of atoms
Mass
If the temperature of a gas changes, but the number of moles and volume remain constant, Pressure also changed. Therefore, option B is correct.
What do you mean by pressure ?The amount of force exerted per area is defined as pressure. To generate a large amount of pressure, you can use either a large force or a force applied over a small area.
Pressure is a situation that can have serious consequences if you don't perform well; thus, performing under pressure. It appears to be a life-or-death situation: your reputation, a relationship, your success, or your safety are all at stake. Your inability to distinguish between stress and pressure can be detrimental.
Pressure changes when the temperature of a gas changes but the number of moles and volume remain constant.
Thus, option B is correct.
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Why does a noise sound fainter as you move away from its source?
Answer:
Uhh..Because as you get farther away then you cant hear the sound waves i think
Explanation:
Answer:
because the sound waves can only travel so far and if there is things near the source the waves bounce off of it. Ex: the speaker in the class room wouldn't be quiet, its like the noise went away as i walked down the halls, maybe the walls were blocking the noise
Explanation:
3.25 * 10 ^ 24 molecules of dinitrogen pentoxide would be how many moles?
Answer: 5.4 moles
Explanation:
Dinitrogen pentoxide has a chemical formula of N2O5
Now, based on Avogadro's law:
1 mole of any substance has 6.02 x 10^23 atoms
So, 1 mole of N2O5 = 6.02 x 10^23 molecules
Z moles of N2O5 = 3.25 x 10 ^ 24 molecules
To get the value of Z, cross multiply:
(3.25 x 10^24 molecules x 1mole) = (6.02 x 10^23 molecules x Z moles)
3.25 x 10^24 = (6.02 x 10^23 x Z)
Z = (3.25 x 10^24) ➗ (6.02 x 10^23)
Z = 5.4 moles
Thus, there are 5.4 moles of Dinitrogen pentoxide.
Answer:
5.39
full answer: 5.396878114
Explanation:
divide 3.25*10^24 over 6.022*10^23(which is a mole of anything in particles)
What is the chemical name for the compound If5
Answer:
Iodine pentafluoride
Explanation:
Answer:
Iodine pentafluoride
A 25 g sample of water releases 2913 J as it cools from 50.0°C. Calculate the final temperature of the water. (Water’s specific heat capacity is 4.184 J/g°C) (round answer to 2-3 sig figs)
Answer:
The final temperature is 22.2°C
Explanation:
Step 1:
Data obtained from the question. This includes the following:
Mass (M) = 25g
Heat (Q) = 2913 J
Initial temperature (T1) = 50.0°C
Final temperature (T2) =?
Specific heat capacity (C) = 4.184J/g°C
Step 2:
Determination of the final temperature.
The final temperature can be obtained as follow:
Q = MC(T1 – T2).. Since we are cooling
2913 = 25 x 4.184 (50 – T2)
2913 = 104.6 (50 – T2)
Divide both side by 104.6
50 – T2 = 2913/104.6
50 – T2 = 27.8
Collect like terms
T2 = 50 – 27.8
T2 = 22.2°C
The final temperature is 22.2°C
Question 1 (1 point)
HOW MANY moles of Neon would be contained in 4.0 L of neon gas at 560 kPa and 127 C?
Answer:
0.674 mol
Explanation:
Step 1:
Data obtained from the question.
Volume (V) = 4 L
Pressure (P) = 560 kPa
Temperature (T) = 127°C
Number of mole (n) =?
Step 2:
Conversion to appropriate unit.
For pressure:
101.325 KPa = 1 atm
Therefore, 560 kPa = 560/101.325 = 5.53 atm
For temperature:
Temperature (Kelvin) = temperature (celsius) + 273
temperature (celsius) = 127°C
Temperature (Kelvin) = 127°C + 273 = 400K
Step 3:
Determination of the number of mole of Neon.
The number of mole of Neon can be obtained by using the ideal gas equation as follow:
Volume (V) = 4 L
Pressure (P) = 5.53 atm
Temperature (T) = 400K
Gas constant (R) = 0.082atm.L/Kmol
Number of mole (n) =?
PV = nRT
5.53 x 4 = n x 0.082 x 400
Divide both side by 0.082 x 400
n = (5.53 x 4) /(0.082 x 400)
n = 0.674 mol
The number of mole of Neon is 0.674 mol
To find the number of moles of Neon in 4.0 L of neon gas at 560 kPa and 127 °C, the ideal gas law is used, and approximately 0.674 moles of Neon are found.
The student has asked how many moles of Neon would be contained in 4.0 L of neon gas at 560 kPa and 127 °C. To answer this question, we will use the ideal gas law, which can be stated as PV = nRT where P is pressure, V is volume, n is the number of moles, R is the ideal gas constant, and T is temperature in Kelvin.
First, convert the temperature from Celsius to Kelvin:
T(K) = 127 °C + 273.15 = 400.15 KConvert pressure from kPa to atm:
P(atm) = 560 kPa / 101.325 kPa/atm = 5.528 atmThe ideal gas constant, R, is 0.0821 L·atm/mol·K.
Now, rearrange the ideal gas equation to solve for n (moles):
n = PV / (RT)Plugging the values in, we get:
n = (5.528 atm × 4.0 L) / (0.0821 L·atm/mol·K × 400.15 K)n ≈ 0.672 moles of NeonTherefore, there are approximately 0.674 moles of Neon in 4.0 L of neon gas under the given conditions.
Which of the following is a chemical change?
A.)Butter melts
B.)Metal rusts.
C.)Water boils.
D.)Things dissolve.
Answer:
B.) Metal Rusts.
Thank You ☺️ ☺️.
☆ ★ Make It Brainlist Answer Please.....what ions represent an acid? What ions represent a base?
Explanation:
acid - An acid is a substance or compound that releases hydrogen ions (H+) when in solution. ...
A base is a substance that releases hydroxyl ions (OH-) when in solution. ...
Figure 2.4. ...
pH is a unit of measurement of the concentration of hydrogen ions (H+) and hydroxyl ions (OH-) in an aqueous (water) solution
base - H 3O + is called a hydronium ion, and it makes things acidic. OH - is called a hydroxyl ion and it makes things basic.
What determines the size of an ocean wave?
a. the wave's color
b. the wave's temperature
c. the wave's speed
d. the wave's energy
4. A simple sugar's properties result from
a. Its ratio of amylose to amylopectin
b. How atoms are arranged in its molecules
C. The type of plant that produced it
d. The degree of crystallization
Answer:
b. how atoms are arranged in it's molecules
What is the molality of a solution containing 0.25 g
of dichlorobenzene (C6H4Cl2) dissolved in 10.0 g of
cyclohexane (C6H12)?
Answer : The molality of solution is, 0.170 mole/kg
Explanation : Given,
Mass of dichlorobenzene = 0.25 g
Mass of cyclohexane = 10.0 g
Molar mass of dichlorobenzene = 147.01 g/mole
Formula used :
[tex]\text{Molality}=\frac{\text{Mass of dichlorobenzene}\times 1000}{\text{Molar mass of dichlorobenzene}\times \text{Mass of cyclohexane (in g)}}[/tex]
[tex]\text{Molality}=\frac{0.25g\times 1000}{147.01g/mole\times 10.0g}=0.170mole/kg[/tex]
Therefore, the molality of solution is, 0.170 mole/kg