Answer:
0.324 mol
Explanation:
Mass of one mole or atomic mass of potassium is 39 g. Thus, number of moles in 12.65 g of potassium is 0.32 moles.
What is atomic mass?Atomic mass of an element is the mass of one mole of that element. One mole of an element contains 6.022 × 10²³ atoms. This number is called Avogadro number.
Potassium is 19th element n periodic table. It is an alkali metal in the first group. The atomic mass of potassium is 39 g/mol. This is the mass of one mole of potassium. The chemical symbol of potassium is K.
Given mass of potassium = 12.65 g
atomic mass = 39 g/mol
number of moles in 12.65 g = mass/ atomic mass
no.of moles = 12.65 /39 = 0.32 moles.
Therefore, the number of moles of 12.65 g of potassium is 0.32 moles.
Find more on atomic mass:
https://brainly.com/question/17067547
#SPJ2
HURRY!!!!!! HELP PLEASEEE
To begin the experiment, 1.65g of methane CH4 is burned in a bomb calorimeter containing 1000 grams of water. The initial temperature of water is 18.98oC. The specific heat of water is 4.184 J/g oC. The heat capacity of the calorimeter is 615 J/ oC . After the reaction the final temperature of the water is 36.38oC.
2. Calculate the change in temperature, ΔT. Show your work. (1pt)
3. Calculate the heat absorbed by water. Use the formula qwater = m • C • ΔT
Show your work (2pts)
4.Calculate the heat absorbed by the Calorimeter. Use the formula:
qcal = Ccal • ΔT Show your work. (2pts)
5. The total heat absorbed by the water and the calorimeter can be calculated by adding the heat calculated in steps 3 and 4. The amount of heat released by the reaction is equal to the amount of heat absorbed with the negative sign as this is an exothermic reaction. (2pts)
a.Using the formula ΔH = - (qcal + qwater ) , calculate the total heat of combustion. Show your work.
b. Convert heat of combustion (answer from part a) from joules to kilojoules. Show your work.
6. Evaluate the information contained in this calculation and complete the following sentence: (2pts)
This calculation shows that burning _______ grams of methane [TAKES IN] / [GIVES OFF] energy (Choose one).
7. The molar mass of methane is 16.04 g/mol. Calculate the number of moles of methane burned in the experiment. Show your work. (2pts)
8. What is the experimental molar heat of combustion in KJ/mol? Show your work. (2pts)
9. The accepted value for the heat of combustion of methane is -890 KJ/mol . Explain why the experimental data might differ from the theoretical value in 2-3 complete sentences. (2pts)
10. Given the formula:
% error= |(theoretical value - experimental value)/theoretical value)| x 100
Calculate the percent error. Show your work. (2pts)
The calorimter is equal to the heat released by the reaction. Calculate the heat released by the reaction.
What is the reaction?The reaction to the news can vary depending on who you are speaking to. For some, the news may be welcomed as a sign of progress and a move in the right direction. Others may be apprehensive, uncertain of the potential outcomes or changes that may come as a result. Some may be angry and frustrated, feeling as though the news has been a long time coming and they have not been given a say in the matter.
1. ΔT = 36.38oC - 18.98oC = 17.4oC
2. qwater = m • C • ΔT
qwater = (1000g)(4.184J/g oC)(17.4oC)
qwater = 71376.8 J
3. qcal = Ccal • ΔT
qcal = (615J/ oC)(17.4oC)
qcal = 10666.1 J
4. qreaction = qwater + qcal
qreaction = 71376.8 J + 10666.1 J
qreaction = 82042.9 J
To learn more about reaction
https://brainly.com/question/25769000
#SPJ1
 why don't we ever see solid or liquid oxygen on earth?
I used a stick of (vegan) butter as our example of thinking about how temperature changes the properties of something when it is wamer or cooler.
1. What is something else you could use to describe how temperature affects the properties of when it is warmer or cooler? How does this change whether it is warm or cold. Describe it.
which pollutants come from air? How and why do these form?
Answer:
Air pollution is caused by solid and liquid particles and certain gases that are suspended in the air. These particles and gases can come from car and truck exhaust, factories, dust, pollen, mold spores, volcanoes and wildfires.
Explanation:
1. Cierta muestra fue diluida así: 1 mL MP se agrega 4mL de agua, luego se extrae 0,5 mL y se lleva a 5 mL y de esta última se obtiene 0,2 y se añade 1,3 de diluyente. Calcule la dilución total.
Answer:
1/375
Explanation:
Primero se debe calcular el factor de dilución para cada dilución seriada. Para ello, se divide el volumen de muestra entre el volumen final de la solución diluida.
1) 1 mL en 1 mL + 4 mL = 5 mL
D1 = 1 mL/5 mL = 1/5
2) 0,5 mL en 5 mL
D2 = 0,5 mL/5 mL = 1/10
3) 0,2 mL en 0,2 mL + 1,3 mL = 1,5 mL
D3 = 0,2 mL/1,5 mL = 2/15
La dilución total se calcula como el producto de las diluciones seriadas realizadas:
DT = D1 x D2 x D3 = 1/5 x 1/10 x 2/15 = 1/375
Part A
Campers want a travel cup that keeps the temperature of a beverage from changing for up to two hours.
They may want to keep a hot drink hot when they are in a cold place. Or they may want to keep a cold drink
from warming up in a hot environment,
Describe how you plan to design, build, and test a travel cup that uses thermal insulators?
The statement is "thermal insulators of a double-layered vacuum seal make a liquid heated when it's cold and keep it cool when it's hot."
What is thermal insulator?A thermal insulator is a material that inhibits heat from being conveyed from one location to another.
Campers seek a travel cup that cools liquids with a cold pack. Design the exterior portion of the cup to keep the drink cold after it has cooled down, as well as the interior compartment to contain the cold pack and channel heat from the liquid in the cup. One of the greatest ways to keep your coffee hot for a long time is to use vacuum insulation in a thermos. On the surface, the concept appears straightforward.
To know more about thermal insulators here
https://brainly.com/question/1033537
#SPJ2
help? It would honestly mean a lot :(
Answer:
1 1
5 2
6 1
8 3
10 3
6 3
9 3
13 3
Explanation:
First of you add the subscripts (the little numbers after the letters) and multiply the big numbers before the letters together to get the number of atoms
For Example:
O= 1 atom
Si{2}= 2 atoms
Mg{5}C{6}= 11 atoms
3Na{2}= 6 atoms
O(SiNa){2}= OSi{2}Na{2}= 5 atoms
Each Capital letter is a new Element
For Example:
O = 1 Element
NaSi = 2 Elements
Write a short paragraph about how gases are all around you. Provide at least 2 examples
Answer:fart and carbon are all around is
Explanation:
A projectile is projected with an initial velocity of 40 m/s at a 45o angle to the horizontal. , calculate the total time travelled.
Answer:
5.77 s
Explanation:
From the question,
The total time travelled by the projectile = Time of flight (T)
T = 2usinθ/g............ Equation 1
Where T = Time of Flight of the projectile, u = Initial velocity, θ = Angle of projection to the horizontal, g = acceleration due to gravity
Given: u = 40 m/s, θ = 45°
Constant: g = 9.8 m/s²
Substitute these values into equation 1
T = 2(40)sin(45°)/9.8
T = 80sin(45°)/9.8
T = 80×0.7071/9.8
T = 5.77 s
1. A student mixes two liquids together and notices that a white solid has formed
at the bottom of the container.
What can the student conclude?
1. A precipitate has formed.
2. A physical change has occurred.
3. A chemical reaction has occurred.
4. A chemical change has occurred.
Answer:
3. A chemical reaction has occured
A student mixes two liquids together and notices that a white solid has formed at the bottom of the container which means precipitate has formed.
What is precipitation reaction ?
Precipitation is the process of creating an insoluble compound in chemistry by either reacting two salts or altering the temperature to alter the solubility of the compound. Additionally, the solid that results from a precipitation reaction is referred to as "precipitate."Precipitation can be a sign that a chemical reaction has taken place, but it can also happen if the concentration of a solute is higher than its solubility. The process of small, insoluble particles aggregating together or forming an interface with a surface, such as the container wall or a seed crystal, is known as nucleation, and it occurs before precipitation.Precipitation is the process of transforming a liquid into a solid. A precipitant is a chemical that gives rise to a solid in a liquid solution. The term "precipitate" refers to the resulting solid. In the event that the molecule size of the insoluble compound is tiny or there is deficient gravity to attract the strong to the lower part of the compartment, the hasten might be equitably dispersed all through the fluid, shaping a suspension. Any process that separates the precipitate from the solution's liquid portion, known as the supernatant, is referred to as sedimentation. Centrifugation is a common technique for sedimentation. A "flower" is a powder that forms after the precipitate has been recovered.
To know more about precipitation check this:
brainly.com/question/18109776
#SPJ2
Which pieces of equipment are
needed to calculate the velocity of a
falling object?
A stopwatch and balance
B speedometer and magnet
C compass and tape measure
D tape measure and stopwatch
Please help me on this
Answer:
the answer is 3(decay) and
the second isa 1(alfa particle) has a mass of equal to helium nucleus
What is the mass of 5.6 moles of Iron (III) Oxide?
Answer:
312.731
Explanation:
it had a long answer but im sure ur teacher wanted u to round it
hope this helps!
~goldfishareswag/brianna
:)
please help me with this question
Answer: I believe it would be B. Genus
Explanation:
I looked up the definitions for you and genus is defined as the group above species. Picture of definition attached.
Which of the following is a TRUE statement?
a.
A molecule always has three types of elements present
b.
Compounds always include the elements hydrogen and sodium
c.
Compounds include things we use in our everyday lives
d.
All elements prefer to hang out with other elements and form molecules
Answer:
b
Explanation:
In the future what two planets will earth resemble?
Answer:
Venus and Mars?
Explanation:
what is 606 as a 2 sig fig answer?
6, 0
thats the answer, i hope it helps
Calculate the value of Key in the following reaction if the equilibrium concentrations are
[H2S] -0.25 M, (H2) - 0.88 M, [S2] -0.44M.
2 H2Sig) = 2 H2(g) + S218)
Answer:
The value of the equilibrium constant Kc is 5.45
Explanation:
The "Law of Mass Action" states:
"For a reversible reaction in chemical equilibrium at a given temperature, it is true that the product of the concentrations of the products raised to the stoichiometric coefficients divided by the product of the concentrations of the reactants raised to their stoichiometric coefficients is a constant."
This constant was called the equilibrium constant. For a reaction:
aA + bB ⇄ cC + dD
the equilibrium constant Kc is:
[tex]Kc=\frac{[C]^{c} *[D]^{d} }{[A]^{a} *[B]^{b} }[/tex]
In this case, the balanced reaction is:
2 H₂S → 2 H₂ + S₂
So, the equilibrium constant Kc is:
[tex]Kc=\frac{[H_{2} ]^{2} *[S_{2} ] }{[H_{2} S]^{2} }[/tex]
The equilibrium concentrations are
[H₂S] =0.25 M[H₂]= 0.88 M[S₂]= 0.44MReplacing in the definition of equilibrium constant:
[tex]Kc=\frac{(0.88 M)^{2} *0.44 M }{(0.25 M)^{2} }[/tex]
Solving:
Kc= 5.45
The value of the equilibrium constant Kc is 5.45
The pressure in a Red Rider BB gun cartridge is 1.5 atm. If the rifle was at 25 °C prior to firing, what is the temperature change of the cartridge after firing if the cartridge reaches standard air pressure of 1.0 atm?
Answer:
–99 °C
Explanation:
From the question given above, the following data were obtained:
Initial pressure (P₁) = 1.5 atm
Initial temperature (T₁) = 25 °C
Final pressure (P₂) = 1 atm
Change in temperature (ΔT) =?
Next, we shall determine the final temperature. This can be obtained as follow:
Initial pressure (P₁) = 1.5 atm
Initial temperature (T₁) = 25 °C + 273 = 298 K
Final pressure (P₂) = 1 atm
Final temperature (T₂) =?
P₁/T₁ = P₂/T₂
1.5 / 298 = 1 / T₂
Cross multiply
1.5 × T₂ = 298
Divide both side by 1.5
T₂ = 298 / 1.5
T₂ = 199 K
Converting 199 K to °C, we have:
T(°C) = T(K) – 273
T₂ = 199 – 173
T₂ = –74 °C
Finally, we shall determine change in temperature. This can be obtained:
Initial temperature (T₁) = 25 °C
Final temperature (T₂) = –74 °C
Change in temperature (ΔT) =?
ΔT = T₂ – T₁
ΔT = –74 – 25
ΔT = –99 °C
Thus, the change in the temperature is –99 °C
H IT H-C --H + Ħ Н The model above shows the structural formula for ethane. What is the chemical formula for ethane? OA. C2H6 OB. 2CH3 Oc. 8CH OD. C6H2
Answer:
B
Explanation:
_____________Makes the particles of the solvent and the solute move around more and come in contact more often. More contact, more opportunity for dissolving.
Answer:
Solvation
Explanation:
Solvation is the name of the process in which the particles of the solute are surrounded by the particles of the solvent molecules and they together mix together to form a solution.
In order words, it is a process of the surrounding solute particles with the solvent particles in order to form a solutions. When the water is the solvent, the process is known as hydration.
It only occurs when the particles of the solvent and solute are in contact with each other and the opportunity for the dissolving process is more when more is the contact between the particles.
The shape of the directly sunlit portion of the Moon as viewed from
Earth
your answer:
lunar phases
What is the Great Red Spot on Jupiter?
Answer:
The Great Red Spot is a storm in Jupiter's southern hemisphere with crimson-colored clouds that spin counterclockwise at wind speeds that exceed those in any storm on Earth. The Great Red Spot has slowly changed over the years, and is currently about 1.3 times as wide as our planet.
moreee help science plsssssssssssssssss helpp
The figure shows a nutrition label. How much energy does this food contain?
Answer:
i need help with that too.
Explanation:
Why does the moon have a stronger gravitational effect on the earth then the sun?
Explanation:
The tidal forces of the Moon are much stronger than the Sun's because it is so much closer to our planet, causing a much greater variation in the gravitational force from one location to another. The Sun's gravitational force, on the other hand, varies much less because the Sun is so far.
Please mark me has brainliestPLEASE HELP No links or fake answers or ill report you and every question you have ever answered to getnur acc deleted. I have no idea how to shower these. Ty if you help and I will give brainliest and like and 5 stars. xx
Answer:
!dk bestie i tried to do it but i cant maybe someone else can figure it or they already did :( anyway i hope you have a amazing day luv <3
how humans can improve the negative aspects of soil use FULL SENTENCES 50 POINTS PLEASE HELP
Answer:
Using diverse nutrient sources can help maintain soil health. Manure and compost add organic matter as well as an array of nutrients, but using just compost or manure to meet the nitrogen needs of the crop every year can result in excessive phosphorus levels in the soil.
pleaaseeee help im failing so bad3
How can you control the flow of power in a circuit?
There are multiple ways to prevent these situations from occurring. The three most common protective devices are fuses, circuit breakers, and surge protectors
Explanation: