What’s this answer help me out
A student dissolves 12.1 g of potassium chloride (KCl) in 250. g of water in a well-insulated open cup. He then observes the temperature of the water fall from 21.0 °C to 17.1 °C over the course of 6.9 minutes. Use this data, and any information you need from the ALEKS Data resource, to answer the questions below about this reaction:
KCl(s) → K (aq) + Cl (aq)
a. Is this reaction exothermic, endothermic, or neither?
b. Calculate the reaction enthalpy ΔH.rxn per mole of KCI.
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
The spot on the fault where the pressure first releases is called the
Answer:
This movement releases energy and generates seismic waves that can be recorded by specialized instruments used by scientists. The point on a fault at which the first movement or break occurs during an earthquake is called the earthquake's hypocenter
Explanation:
A compound is 22.5% nitrogen and 77.5% oxygen, What is the empirical formula of
this compound?
Answer:
[tex]NO_3[/tex]
Explanation:
Hello!
In this case, since percent compositions are used to set up empirical formulas when assuming those percentages are masses, we can fist compute the moles of nitrogen and oxygen in the compound as shown below:
[tex]n_N=22.5g/14.01g/mol=1.61mol\\\\n_O=77.5g/16.00g/mol=4.84mol[/tex]
Now, we divide by the fewest moles to compute the subscripts:
[tex]N=\frac{1.61}{1.61} =1\\\\O=\frac{4.84}{1.61} =3[/tex]
Thus, the empirical formula turns out:
[tex]NO_3[/tex]
Best regards!
A flask at room temperature contains exactly equal amounts (in moles) of nitrogen and xenon.
a. Which of the two gases exerts the greater partial pressure?
b. The molecules or atoms of which gas have the greater average velocity?
c. The molecules of which gas have the greater average kinetic energy?
d . If a small hole were opened in the flask, which gas effuses more quickly?
Answer:
a) Same
b) Nitrogen
c) Same
d) Nitrogen
Explanation:
a)
The formula for partial pressure of a gas is equal to
[tex]p_B = n_B \frac{RT}{V}[/tex]
Here nB is the number of moles .
The number of moles for both the gases are same and hence the partial pressure for the two gases will also be same.
b) The greater average velocity is calculated by using following formula
[tex]v_{RMS} = \sqrt{3RTM}[/tex]
Here M is the molar mass.
Molar mass of nitrogen is greater than the molar mass of xenon and hence nitrogen will have higher greater average velocity
c) As we know, the average kinetic energy of gas particles is dependent on the absolute temperature of gas and if all the gases are at same temperature, their kinetic energy will also be same. Since nitrogen and xenon are at same temperature, their kinetic energy will be same
d) Effusivity is depended directly on the thermal conductivity, density and and the specific heat capacity.
All these three parameters are higher in case of nitrogen. Thus, it will effuse first
g Which of the following solutes in aqueous solution would be expected to exhibit the smallest freezing-point lowering (assuming ideal behavior)? In other words, which one would have the highest freezing point temperature? A) 0.20 m CaCl2 B) 0.50 m C2H5OH (ethanol) C) 0.10 m Al(NO3)3 D) 0.25 m NH4Br E) 0.30 m NaCl
Answer:
0.10 m Al(NO3)3
Explanation:
Let us note that the substance that has the highest freezing point will have the lowest freezing point depression. Since;
ΔTf = Kf m i
ΔTf = freezing point depression
Kf = freezing point constant
m = molality
i = Van't Hoft factor
Given that the freezing point depression depends on the molality and the Van't Hoft factor (number of particles), we can see that 0.10 m Al(NO3)3 has the least freezing point depression and highest freezing point temperature because it gives the least value of m * i. That is 0.10 m * 4 = 0.4
Dos Identy each statement whether TRUE or FALSE. Write you answer m
1. Mammals are warm blooded animals that are born alive.
2. Reptiles are cold blooded vertebrates that are hatched from egs.
3. Vertebrates have no economic importance to our environment.
4. There is a significant relationship between vertebrates
5. Invertebrate animals are important to human beings.
and invertebrates.
Answer:
1=true
2=false
3=false
4=true
5=true
Plsss help
a. Given that the density of oxygen is 1.439 g/L, how many liters of oxygen gas
can be produced if 5.0 moles of mercury (II) oxide are heated?
Which term names an icy object that orbits the sun and has a tail?
meteorite
comet
meteor
asteroid
Answer:
Comets are small, icy objects that have very elliptical orbits. When they are close to the Sun, they form comas and tails, which glow and make the comet more visible.
Explanation:
Hope This Helps!!
(brainliest please, if possible)
Answer:
comet's
Explanation:
what the other user said
Sodium chloride (NaCl) is commonly used to melt ice on roads during the winter. Calcium chloride (CaCl2) is sometimes used for this purpose too. Let us compare the effectiveness of equal masses of these two compounds in lowering the freezing point of water by calculating the freezing point depression of solutions containing 220. g of each salt in 1.00 kg of water. (An advantage of is that it acts more quickly because it is hygroscopic, that is, it absorbs moisture from the air to create a solution and begin the process. A disadvantage is that this compound is more costly.) Assume full dissociation of ionic compounds. Kfp(H2O)= -1.86 °C/m.
ΔTfp= _________°C for NaCl
ΔTfp=_________ °C for CaCl2
Answer:
[tex]\Delta Tfp_{NaCl}= -14.0\°C\\\\\Delta Tfp_{CaCl_2}=-11.1\°C[/tex]
Explanation:
Hello!
In this case, since the freezing point depression caused by the addition of a solute, we use the following formula:
[tex]\Delta Tfp= i*m*Kfp[/tex]
Thus, we first need to compute the molality of each solute, as shown below:
[tex]m_{NaCl}=\frac{220.g/(58.44g/mol)}{1.00kg} =3.76m\\\\m_{CaCl_2}=\frac{220.g/(110.98g/mol)}{1.00kg} =1.98m[/tex]
Next, since NaCl has two ionic species, one Na⁺ and one Cl⁻, and CaCl₂ three, one Ca²⁺ and two Cl⁻, the van't Hoff's factors are 2 and 3 respectively, therefore the freezing point depressions turn out:
[tex]\Delta Tfp_{NaCl}= 2*3.76m*-1.86\°C/m=-14.0\°C\\\\\Delta Tfp_{CaCl_2}= 3*1.98m*-1.86\°C/m=-11.1\°C[/tex]
It means that CaCl₂ is still better than NaCl because produces involves a higher melting point for the ice, so it would melt faster.
Best regards!
What would be the structural formula for sodium fluoride? (NaF)
Answer:
Formula and structure: The chemical formula of sodium fluoride is NaF and its molar mass is 41.99 g/mol. It is a simple ionic compound, made of the sodium (Na +) cation and fluoride (F -) anion. The solid salt exists as cubic crystals similar to the crystal structure of sodium chloride (NaCl).
Explanation:
What is an oceanographer likely to find in a typical sample of salt water from the
ocean floor?
Water with high salt content, low in temperature, and low in density.
Water with average salt content, high in temperature, and high in density.
Water with high salt content, high in temperature, and high in density.
Water with high salt content, low in temperature, and high in density.
Explanation:
the oceanographic is likely to find water with high salt content, low in temperature and high in density
Water with high salt content, low in temperature, and high in density likely to find in a typical sample of salt water from the ocean floor. Therefore, the correct option is option D.
What is an oceanography?Oceanography, also known as oceanology as well as ocean science, is indeed the scientific paper of the seas. The term is derived from the Ancient Greek words "ocean" (v) and "writing" (graph), respectively.
Geophysical fluid dynamics, plate tectonics, the geology of the ocean floor, and fluxes of different chemical compounds and physical qualities both inside and across the ocean are all factors that affect waves and ocean currents. Water with high salt content, low in temperature, and high in density likely to find in a typical sample of salt water from the ocean floor.
Therefore, the correct option is option D.
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You are given a sample of several compounds to separate by paper chromatography. You draw a pencil line exactly 1.00 cm from the bottom of the paper, and place a spot of sample on it. You dry the sample, then develop it in a solvent. When the chromatogram is taken out of the solvent, the paper is wet up to 9.2 cm from the bottom of the sheet. The compound you are interested in shows up as a spot 7.1 cm from the bottom of the paper. Calculate the following:
a. How far did the compound move?
b. In the same time, how far did the solvent move?
c. What is the Rf factor for the compound?
Answer:
a) 6.3 cm
b) 8.0 cm
c) 0.7875
Explanation:
(a) The compound has moved above upto 7.3 cm from the bottom of the paper. Let us assume that line is drawn at 1.0 cm mark as the origin of spot. \
Distance traversed by compound= 7.3 - 1.0 cm = 6.3 cm
(b) Distance traversed by the solvent = 9.0 - 1.0 cm = 8.0 cm
(c) The Rf = Compound Migration distance / Solvent front migration distance
= 6.3/8.0 = 0.7875
What element does Ca-37 turn into when it gives off radiation?
K-37
K-39
Sc-37
Sc-45
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 producedA flexible container is filled with He(g) to a volume of V1 at a temperature of 150K. The container is then heated at constant pressure to a temperature of 300K. What is the final volume of the container?
a. V1/3b. V1/2c. V1d. 2V1
Answer:
a but it might also be c
Explanation:
i d k what this is
Answer:
2V1
Explanation:
In an experiment, 20cm^3 of 0.2dm^3 NaOH reacted with 32.0cm^3 of H2SO4 solution. Calculate the concentration of the H2SO4 in a) mol dm^-3 and b) g dm^-3
Answer:
A. 0.0625 moldm¯³
B. 6.125 gdm¯³
Explanation:
We'll begin by writing the balanced equation balance equation for the reaction. This is illustrated below:
2NaOH + H₂SO₄ —> Na₂SO₄ + 2H₂O
From the balanced equation above,
The mole ratio of the acid, H₂SO₄ (nₐ) = 1
The mole ratio of the base, NaOH (n₆) = 2
A. Determination of the concentration of the acid in moldm¯³.
Volume of base, NaOH (V₆) = 20 cm³
Concentration of base, NaOH (C₆) = 0.2 moldm¯³
Volume of acid, H₂SO₄ (Vₐ) = 32 cm³
The mole ratio of the acid, H₂SO₄ (nₐ) = 1
The mole ratio of the base, NaOH (n₆) = 2
Concentration of acid, H₂SO₄ (Cₐ) =?
CₐVₐ / C₆V₆ = nₐ / n₆
Cₐ × 32 / 0.2 × 20 = 1 / 2
Cₐ × 32 / 4 = 1 / 2
Cross multiply
Cₐ × 32 × 2 = 4 × 1
Cₐ × 64 = 4
Divide both side by 64
Cₐ = 4 / 64
Cₐ = 0.0625 moldm¯³
Therefore, concentration of the acid in moldm¯³ is 0.0625 moldm¯³
B. Determination of the concentration of the acid in gdm¯³.
Concentration (moldm¯³) = 0.0625 moldm¯³
Concentration (gdm¯³) =?
Next, we shall determine the molar mass of the acid, H₂SO₄. This can be obtained as follow:
Molar mass of H₂SO₄ = (2×1) + 32 + (4×16)
= 2 + 32 + 98
= 98 g/mol
Finally, we shall determine the concentration of the acid in gdm¯³. This can be obtained as follow:
Concentration (moldm¯³) = 0.0625 moldm¯³
Molar mass of H₂SO₄ = 98 g/mol
Concentration (gdm¯³) =?
Conc. (moldm¯³) = conc. (gdm¯³) / Molar mass
0.0625 = Conc. (gdm¯³) / 98
Cross multiply
Conc. (gdm¯³) = 0.0625 × 98
Conc. (gdm¯³) = 6.125 gdm¯³
Thus, the concentration of the acid in gdm¯³ is 6.125 gdm¯³
7. A family used 1,438 kilowatt-hours (kwh) of electricity during the month of
October. Express this amount of energy in joules and Btu. See Appendix A.
Can you please show the steps thanks
Answer:
Im bad at math sorry
Explanation:
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:
For case 1, what happens when an electron jumps from energy level 1 to energy level 3 in an atom?
Answer:
Case 1 (energy level): In an atom, an electron jumps from energy level 1 to energy level 3. ... The energy will increase.
Explanation:
Name the following alkene compound
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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which acide will have more strength
out of two acids of pH
value 2
and 5 why
Ph 2 will ahve more strength due to the fact that its more acidic compared to pH 5.
the lower the number of a pH, the more it is heading towards being acidic, but the higher the number, the more it heads towards being an alkali. here is a ppt i made along time ago. hope it can help you . have a nice day
1. What is an ionic bond?
Ionic bonding is the complete transfer of valence electron(s) between atoms. It is a type of chemical bond that generates two oppositely charged ions. In ionic bonds, the metal loses electrons to become a positively charged cation, whereas the nonmetal accepts those electrons to become a negatively charged anion.
Explanation:
ionic bond is a bonding between a non-metal and a metal, that occurs when change atoms (ions) attract.
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:
what is the relationship between temperature and kinetic energy?
Answer:
Temperature is directly proportional to the kinetic energy of the atoms that a body is made of. This relation is valid concerning the velocities relative to the center of mass of the body. In other words, concerted movements like translation and rotation do not affect temperature.
Explanation:
Answer:
As stated in the kinetic-molecular theory, the temperature of a substance is related to the average kinetic energy of the particles of that substance. When a substance is heated, some of the absorbed energy is stored within the particles, while some of the energy increases the motion of the particles.
I hope it's helpful!
Looking at the following equation, which is the correct order of coefficients?
NH3 + O2 --> NO + H2O
2NH3 + 302---> 2NO + 3H20
If plant a, the parent plant, died from a new disease, what might happen to plant B?
Which of the following is the best example of water changing from a liquid to a gas?
A. clouds on a summer day
B. morning dew on orange trees
C. fog rising from a pond on a cold day
D. ice melting back to water when it is left out at room temperature
Answer:
c
Explanation:
hope this helps! ^-^
Answer:
C
Explanation:
It's the answer
What types of energy do lamps give off?
Include how was your day in you answer.
Explain why/if the lamp gives off heat energy.
Answer:
When a lamp is turned on, it gives off light energy and heat energy.
My day was fantastic.
Explanation:
The lamp gives off heat energy because anything that gives off light energy gives off heat energy.
