Answer:
a. Endothermic
b. 26.37kJ/mol
Explanation:
a. As we can see, the temperature of the water is decreasing when the reaction is occurring, that means the reaction is absorbing heat and is endothermic
b. To find the enthalpy we must find the change in heat when 12.1g of KCl are dissolved. Using the equation:
Q = -m*ΔT*C
Where Q is change in heat
m the mass of solution (250g + 12.1g = 262.1g)
ΔT is change in heat (17.1°C - 21.0°C = -3.9°C)
And C is specific heat of the solution (4.184J/g°C assuming is the same than the specific heat of water).
Replacing:
Q = -262.1g*-3.9°C*4.184J/g°C
Q = 4277J = 4.28kJ
As reaction enthalpy is the change in heat per mole of reaction, we must find the moles of 12.1g of KCl:
Moles KCl -Molar mass: 74.55g/mol-:
12.1g KCl * (1 mol / 74.55g) = 0.1623 moles KCl
The reaction enthalpy us:
4.28kJ / 0.1623mol = }
26.37kJ/mol
Name the following alkene compound
how many litres of hydrogen is present in 12 grams of hydrogen
Answer:
10 the power of 23 hydrogen atom
What are the main parts of a simple electrie motor, like the one found inside a remote control car? O a generator, wires, and turbine magnets and coils of wire O electromagnets only
Answer:
A DC power supply, commutator, rotor armature, axle, and a field magnet.
QUESTION 7 Can you use alligation for any type of liquid?
Answer:
Yes you can use alligation for a type of liquid. Explanation: Alligation is an old and practical method of solving arithmetic problems related to mixtures of ingredients.
Matter are anything that is made up of atoms. The quantity of matter can be observed only on the basis of mass and volume calculation. Thus, we can use allegation for any type of liquid.
What is matter?
Matter is a substance that has some mass and can occupy some volume. The matter is mainly used in science. Matter can be solid, liquid or gas.
Matter is anything that is made up of atoms. Anything around us that can be physically seen and touched are matter. Ice, water and water vapors are example of matter.
Mass can also be represented as number of molecules. We also saw that matter occupy some volume and that volume is measured only in liter. Allegation is a form of liquid that we may utilize. Allegation is a time-tested and useful strategy for tackling mathematical issues involving combinations of elements.
Thus, we can use allegation for any type of liquid.
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The mass of a dust particle would be measured in?
Beryllium oxide, Beo, is an electrical insulator. How
many moles of beryllium oxide qre in a 250 gram
sample of the compound?
Answer:
There are 10.0 moles of beryllium oxide in a 250 grams sample of the compound.
Explanation:
We can calculate the number of moles (η) of BeO as follows:
[tex] \eta = \frac{m}{M} [/tex]
Where:
m: is the mass = 250 g
M: is the molar mass = 25.0116 g/mol
Hence, the number of moles is:
[tex] \eta = \frac{250 g}{25.0116 g/mol} = 10.0 moles [/tex]
Therefore, there are 10.0 moles of beryllium oxide in a 250 grams sample of the compound.
I hope it helps you!
MEDICAL FORENSICS
please help me i only get one chance to do this please
Answer:
i think the answer is b temperature
Answer:
no
Explanation:
Help pls! I need help im just writing to use the character limit!
Answer:
se que la imaje es un poco confusa con la materia pero
desiaria ayudarte pero CREO que con mi TÉCNICA es la A
How many moles are in 8.30 X 1023 molecules of H2O? with the step
Answer:
Answer: 1.38 moles
Explanation: According to Avogadro's law, 1 mole of every substance contains Avogadro number of particles (atoms, molecules or ions) i.e.6.023*10^23 particles.
Given : 1 mole molecule of water contains 6.023*10^23 molecules of water.
6.023*10^23 molecules are present in = 1 mole
8.30*10^23molecules will be present in =
1/6.023*10^23 ×8.30*10^23=1.38 moles
Thus molecules is equal to 1.38 moles.
PLEASE MARK ME BRAINLIEST
How are scientists trying to use a plant catalyst to create solar fuels? Someone please answer?
Answer:
plants can be used as fuel because plants can be burned so they compose the plants to make a liquid
A fly hits a windshield of a truck. The truck exerts a force on the fly, and
the fly exerts an equal and opposite force back on the windshield.
A. Newton’s first law
B. Newton’s second law
C. Newton’s third law
Answer:
A fly hits a windshield of a truck.
Explanation:
newton's first law
Determine if the bond between atoms in each example below is nonpolar covalent, polar covalent, or ionic a. H-H b. P-Cl c. F-F d. Na-Br e. N-F f. Mg-O g. C-H h. H-Cl
Answer:
a nonpolar covalent
b polar
c nonpolar
d ionic
e. polar
f. ionic
g polar
h polar
Explanation:
Define atmosphere and list any three ways in which
the atmosphere is useful for the survival of living
things.
Answer:
Explanation:
Atmosphere - the envolpoe of gasses sourounding the earth or another planet or the air in any particular place. The atmosphere protects us from the suns harmful rays, carrys cloud full of water so it can rain all over the world, and have oxygen, which is nessecary for survival to all living things.
A balloon is filled with 30L of helium gas at 1atm.What is the volume when balloon rises to an attitude where the pressure is only 0.25 atm?
Answer:
[tex]V_2=120L[/tex]
Explanation:
Hello!
In this case, since Helium is undergoing a volume-pressure change, according the Boyle's law, we infer the following equation is used:
[tex]P_1V_1=P_2V_2[/tex]
Thus, since we are not given the volume at 0.25 atm, we can solve for V2 to do so:
[tex]V_2=\frac{P_1V_1}{P_2}[/tex]
Thus, we plug in to obtain:
[tex]V_2=\frac{1atm*30L}{0.25atm}=120L[/tex]
Best regards!
The final volume of the balloon at the given altitude is 120 L.
The given parameters;
initial volume of the balloon, V₁ = 30 Linitial pressure, P₁ = 1 atmfinal pressure of the balloon, P₂ = 0.25 atmThe final volume of the balloon at the given altitude is calculated by applying Boyles law as follows;
[tex]P_1 V_1 = P_2 V_2\\\\V_2 = \frac{P_1V_1}{P_2} \\\\V_2 = \frac{30 \times 1 }{0.25} \\\\V_2 = 120 \ L[/tex]
Thus, the final volume of the balloon at the given altitude is 120 L.
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A 75.0 sample of a natural product isolated from alfalfa hay was dissolved in water to make 100.0 mL of solution. The solution did not conduct electricity and has an osmotic pressure of 0.246 atm at 27.0c. What is the molar mass of this compound
Answer:
Sorry i dont know
Answer:
What is the vapor pressure of an aqueous solution that has a solute mol fraction of c = 0.100? The vapor pressure of water is 25.756 mm Hg at 25°C.
12) The vapor pressure of an aqueous solution is found to be 24.9 mm Hg at 25°C. What is the mole fraction of solute in this solution? The vapor pressure of water is 25.756 mm Hg at 25°C.
9) Determine the molarity of an aspirin solution that produces an osmotic pressure of 0.0555 atm at 25°C (i = 1).
10) A saline solution is administered intravenously to patients who cannot take fluid orally and are in danger of dehydration. The osmotic pressure of this solution must match that of blood to prevent hemolysis or crenation of blood cells. What mass of sodium chloride (58.44 g/mol) is needed to produce 100.0 mL of saline solution with an osmotic pressure of 7.83 atm at a body temper
Explanation:
What is the percentage by mass of chromium in sodium dichromate (VI) Na2
Cr2
O7
?
Answer:
39.7%
Explanation:
To obtain the percentage composition of chromium (Cr) in Na₂Cr₂O₇, do the following:
Molar mass of Na₂Cr₂O₇ = (23×2) + (52×2) + (16×7)
= 46 + 104 + 112
= 262 g/mol
Mass of Cr in Na₂Cr₂O₇ = 2 × 52 = 104 g
Percentage composition of Cr = mass of Cr / Molar mass of Na₂Cr₂O₇ × 100
= 104 / 262 × 100
= 39.7%
Thus, the percentage composition of chromium (Cr) in Na₂Cr₂O₇ is 39.7%
Why does there appear to be another duck head in the water?
A
The water in the pond reflects light from the Sun, making a mirror image
B
The molecules in the atmosphere refract the light, splitting it into two ima
С
The duck scatters the light, making hundreds of tiny refractions that collec
D
The bottom of the pond absorbs the light, then projects it toward the surfa
Answer:
it's A. The water in the pond reflects light from the Sun, making a mirror image
Explanation:
i just took the test
List out fifteen ways of how you use water in your everyday life
Answer:
Drinking water
Showering
Brushing your teeth
Cooking
Doing Laundry
Washing your hands
Watering Plants
Cleaning dishes
Recreation; such as swimming pools
Used to grow food
Explanation:
How many moles of hydrogen sulfide are contained in a 77.7-8 sample of this gas?
Select one:
o
a. 0.44mol
O b.4.56mol
O c. 38.5mol
O d. 111.8mol
e. 2.28mol
Answer:
its either C or D my guess is C though because 35.0g of hyddrogen is =1.03 mol
Explanation:
What happens if excess carbon dioxide is not removed from the atmosphere?
A) a decrease in the amount of fossil fuels availabe
B) it may lead to global warming
C) more dead plants and animals not decomposing before getting buried
D) increase in the amount of fossils fuels available
please help fast I need to bring my grade up I'll give 30 points.
Answer:
Carbon dioxide becomes a poisonous gas when there is too much of it in the air you breathe. Besides the effects it can have on the planet and the atmosphere, carbon dioxide poisoning can lead to central nervous system damage and respiratory deterioration in humans and other breathing creatures.
Answer:
Carbon dioxide becomes a poisonous gas when there is too much of it in the air you breathe. Besides the effects it can have on the planet and the atmosphere, carbon dioxide poisoning can lead to central nervous system damage and respiratory deterioration in humans and other breathing creatures.
Explanation:
Hope This Helps! [ :
Decide whether a chemical reaction happens in either of the following situations. If a reaction does happen, write the chemical equation for it. Be sure your chemical equation is balanced and has physical state symbols. situation chemical reaction.
A strip of solid tin metal is put into a beaker of 0.074M MgBr2 solution .
Answer:
Sn(s) + MgBr2(aq) --> SnBr2(aq) + Mg(s)
Explanation:
Decide whether a chemical reaction happens in either of the following situations.
- A reaction happens. The type of this reaction is the single replacement reaction.
If a reaction does happen, write the chemical equation for it.
Sn(s) + MgBr2(aq) --> SnBr2(aq) + Mg(s)
Which of the following is true?
A)If we know that a reaction is an elementary reaction, then we know its rate law.
B)The rate-determining step of a reaction is the rate of the fastest elementary step of its mechanism.
C)Since intermediate compounds can be formed, the chemical equations for the elementary reactions in a multistep mechanism do not always have to add to give the chemical equation of the overall process.
D)In a reaction mechanism, an intermediate is identical to an activated complex.
E)all of these statements are true.
Answer:
If we know that a reaction is an elementary reaction, then we know its rate law.
Explanation:
An elementary reaction is a reaction that takes place in one reactive encounter. This means that the two species interact in a single step to give the products.
If two reactants interact in a single step to yield the products then we can easily deduce the rate law from the reaction equation.
For instance, For the reaction;
2A + B → C
The rate law is
rate = k[A]²[B].
If the reaction is an elementary reaction and the equation of the reaction is balanced, then we can deduce the rate law from the balanced reaction equation.
The pressure 15.0 m under water is 248 kPa.
What is this pressure in torr
Answer:
1860 torr
Explanation:
In order to convert from kPa to torr, we are going to use the following conversion factor:
1 kPa = 7.5 torrNow we multiply 248 kPa with this factor so that the kPa units cancel each other and only the torr units remain:
248 kPa * [tex]\frac{7.5torr}{1kPa}[/tex] = 1860 torrThis means that the answer is 1860 torr.
What is the activation energy of a reaction?
A. The energy that is given off when a reaction happens
B. The kinetic energy of the colliding molecules
C. The speed at which the molecules must be moving in order to
react
D. The energy the molecules must have in order to react
SUBMIT
Answer:
D i took it aswell
Explanation:
The energy the molecules must have in order to react. Hence, option D is correct.
What is activation energy?Activation energy is the sufficient amount of energy necessary to initiate a chemical reaction.
It can also be said as the minimum amount of energy needed to energize molecules or atoms so that they can undergo a chemical reaction or transformation.
Hence, the energy the molecules must have in order to react.
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What are some positive and negative things about living near a volcano?
HELP ASAP PLS. The melting of a glacier is an example of the interactions among which of Earth’s spheres?
A. geosphere, troposphere, cryosphere
B. atmosphere, geosphere, cryosphere
C. atmosphere, asthenosphere, biosphere
D. hydrosphere, asthenosphere, atmosphere
Answer:
d. hydrospher, asthenosphere, atmosphere
Answer:
its actually b atmosphere, geosphere, cryosphere atmosphere
Explanation: atmosphere is most likely the heat in the air or the water evaporating , cryosphere is the ice that forms the glaciers. and thats how i know im not sure about geosphere but i know its none of the others ones hope this helps :D
Liquid hexane will react with gaseous oxygen to produce gaseous carbon dioxide and gaseous water . Suppose 17.2 g of hexane is mixed with 19. g of oxygen. Calculate the maximum mass of carbon dioxide that could be produced by the chemical reaction. Be sure your answer has the correct number of significant digits.
Answer:
16.5g of CO₂ could be produced
Explanation:
The combustion of hexane occurs as follows:
C₆H₁₄(l) + 19/2O₂ → 6CO₂ + 7H₂O
Where 1 mole of hexane reacts with 19/2 moles of O₂.
To solve this question we need to find the moles of each reactant in order to find limiting reactant. The moles of the limiting reactant will determine the moles of CO₂ produced:
Moles C₆H₁₄ -Molar mass: 86.18g/mol-:
17.2g hexane * (1mol / 86.18g) = 0.200 moles hexane
Moles O₂ -Molar mass: 32g/mol-:
19g O₂ * (1mol / 32g) = 0.594 moles oxygen.
For a complete reaction of 0.594 moles of oxygen are required:
0.594 moles O₂ * (1mol C₆H₁₄ / 19/2 moles O₂) = 0.0625 moles C₆H₁₄.
As there are 0.200 moles of hexane, hexane is the excess reactant and oxygen the limiting reactant.
The moles of CO₂ produced assuming a yield of 100% -All moles of oxygen react producing carbon dioxide.:
0.594 moles O₂ * (6mol CO₂ / 19/2 moles O₂) = 0.375 moles of CO₂ could be produced. The mass is:
0.375 moles of CO₂ * (44.01g / mol) =
16.5g of CO₂ could be producedAn allergy medicine is usually stored in a cabinet at room termperature where its molecules move around each other. By
mistake, an intern transferred energy into the medicine. After one hour, the intern found the medicine and noticed that it
was a liquid. How were the molecules moving when the intern found the medicine? Explain why the molecules were
moving this way after the intern transferred energy ito the medicine.
Answer:
hello, can you pleas egive me the answer? i have the same exact question. thank you!
Explanation:
MQ : Which parts of the brain had most likely been affected?
Answer:
the cerebrum
Explanation:
answer is A
What is the formula for Decaoxygen pentasulfide
Answer:
Compound Formula. 1, Carbon dioxide, CO2. 2, Carbon monoxide, CO. 3, Diphosphorus pentoxide, P2O5. 4, Dinitrogen monoxide, N2O.
Explanation:
dont even know by thoAnswer:
Explanation: