Answer:
Explanation:
The heat of reaction is the energy that is released or absorbed when chemicals are transformed in a chemical reaction. ... The heat of reaction or reaction enthalpy is typically expressed as molar enthalpy in kJ/mol or as specific enthalpy in kJ/kg or kJ/L.
Answer:
The heat of reaction is the energy that is released or absorbed when chemicals are transformed in a chemical reaction. ... The heat of reaction or reaction enthalpy is typically expressed as molar enthalpy in kJ/mol or as specific enthalpy in kJ/kg or kJ/L.
Explanation:
Please help ASAP
Identify the atom with the ground-state electron configuration shown for its valence shell.
3s^2 3p^1
Marked out of 1.50
A student weights his unknown sample on
uncalibrated balance and obtains a weight of
1.0555 g. If the true weight of the unknown sample
is 1.0755 g, what is the % relative error in his
weight measurements?
+0.94٪
- 1.86%
+1.86%
-0.94
Answer:
+.0.94%
Explanation:
Relative and average atomic mass both describe properties of an element related to its different isotopes. Out of these two Relative atomic mas is more accurate. Thus the % relative error in his weight measurements is +.0.94%.
What is mass?Mass defines the quantity of a substance. It is measured in gram or kilogram. Average mass is the mass of atoms of an element that are isotopes. It can be calculated by multiplying mass of a isotope to natural abundance of that isotope.
The relative mass is the mass that is with respect to mass of a matter that is considered as standard. In chemistry relative mass is equal to the mass of one-twelfth the mass of C-12 isotope .
% relative error=(Difference in weight÷ original weight)×100
Difference in weight= original weight -calculated weight
original weight=1.0755 g
calculated weight=1.0555 g
Difference in weight= 1.0755 g-1.0555 g=0.02g
% relative error=(0.02g÷ 1.0755 g)×100
=+.0.94%
Thus the % relative error in his weight measurements is +.0.94%.
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Calculate the number of molecules found in 35 g of Sodium Hydroxide?
Answer:
5.27*10^23 (rounded to 3 significant figures)
Explanation:
The amount of molecules in one mole of anything is equal to Avogadro's number: 6.022×10^23
To find the number of moles of NaOH in 35 grams of it, do 35 divided by the molar mass (39.997): 35/39.997=0.87506562 moles of NaOH
To find the number of molecules, multiply the moles of NaOH by Avogadro's number: 0.87506562×(6.022×10^23)=5.26964522*10^23
Answer:
5.27x10²³ molecules
Explanation:
In order to solve this problem we first convert 35 g of Sodium Hydroxide (NaOH) into moles, using its molar mass:
35 g ÷ 40 g/mol = 0.875 molFinally we convert 0.875 moles into number of molecules, using Avogadro's number:
0.875 mol * 6.023x10²³ molecules/mol = 5.27x10²³ moleculesWhat is a biome?
Question 1 options:
An area with lots of of rainfall.
An area with the same climate, landscape, plants, and animals.
An area with different temperatures.
A bunch of trees, forests, and rivers.
Answer:
An area with the same climate, landscape, plants, and animals.
How many moles of NaOH are contained in 56.0 mL of a 2.40 M solution of 1 point
NaOH in water? (**Use only numerical answers with 3 significant figures.
The units are given in the question.)
Your answer
Answer:
1.34 mol
Explanation:
Molarity, which is the molar concentration of a solution, can be calculated by dividing the number of moles (n) by the volume (V).
That is;
Molarity (M) = n/V
According to the information provided in this question;
M = 2.40M
V = 56.0 mL = 56/1000 = 0.056 L
Since molarity = n/V
number of moles = M × V
n = 0.056 × 24
n = 1.34 mol
Compared to water, metals heat up faster because they have
Answer: the answer would be a lower specific heat.
Explanation:
Pleaseee helpppp!!!!!!!!
Answer:
a covalent would be the two that are nonmetals
The reason for using 1-propanol as the solvent of choice for recrystallization is that triphenylphosphine oxide is more soluble in 1-propanol than the alkene product because triphenylphosphine oxide can use its oxygen to hydrogen-bond to 1-propanol, whereas the alkene has no hydrogen-bonding capability. Triphenylphosphine oxide, therefore, is removed based on its polarity and H-bonding ability.
a. True
b. False
Answer:
True
Explanation:
Hydrogen bonding is a bond that exists between hydrogen and a highly electronegative element such as oxygen, nitrogen, fluorine etc.
The greater solubility of the triphenylphosphine oxide owes to the hydrogen bonded interaction between it and the 1-propanol.
The alkene lacks such hydrogen bonded interaction because it does not have a highly electronegative atom in its structure.
Hence, triphenylphosphine oxide is removed based on its polarity and hydrogen bonding ability.
A city continuously disposes of effluent from a wastewater treatment plant into a river. The minimum flow in the river is 130 m3/s, and the discharge from the treatment plant is 37 m3/s. Upstream from the outfall, the background concentration is 0.69 mg/L. The maximum allowable concentration in the river is 1.1 mg/L. What is the maximum concentration that of the pollutant (in mg/L) that can be safely discharged from the wastewater treatment plant
Answer:
[tex]2.54\ \text{mg/L}[/tex]
Explanation:
C = Allowable concentration = 1.1 mg/L
[tex]Q_1[/tex] = Flow rate of river = [tex]130\ \text{m}^/\text{s}[/tex]
[tex]Q_2[/tex] = Discharge from plant = [tex]37\ \text{m}^3/\text{s}[/tex]
[tex]C_1[/tex] = Background concentration = 0.69 mg/L
[tex]C_2[/tex] = Maximum concentration that of the pollutant
The concentration of the mixture will be
[tex]C=\dfrac{Q_1C_1+Q_2C_2}{Q_1+Q_2}\\\Rightarrow C_2=\dfrac{C(Q_1+Q_2)-Q_1C_1}{Q_2}\\\Rightarrow C_2=\dfrac{1.1(130+37)-130\times 0.69}{37}\\\Rightarrow C_2=2.54\ \text{mg/L}[/tex]
The maximum concentration that of the pollutant (in mg/L) that can be safely discharged from the wastewater treatment plant is [tex]2.54\ \text{mg/L}[/tex].
Consider the following intermediate chemical equations.
P₄(s)+3O₂(g) ---> P₄O₆(s) ΔH₁ = -1640kJ
P₄O₁₀(s) ---> P₄(s)+5O₂(g) ΔH₂ = 2,940.1 kJ
What is the enthalpy of the overall chemical reaction P₄O₆(s)+2O₂(g) ---> P₄O₁₀(s)
A.) -4,580 kJ
B.) -1,300 kJ
C.) 1,300 kJ
D.) 4,580 kJ
Answer:
-1,300 kJ
I don't want to explain it brainly AAAAA
The standard enthalpy of the reaction is the enthalpy change which occurs in a system when a matter is transformed by a chemical reaction under standard conditions. Here the enthalpy of the overall chemical reaction is -1,300 kJ. The correct option is B.
What is enthalpy change?In any general chemical reaction, the reactants undergo chemical changes to form products. The change in enthalpy is represented as ΔrH and is termed as the reaction enthalpy. It can be calculated by subtracting the sum of enthalpies of all the reactants from that of the products.
ΔrH = ∑ aiH products - ∑ bi H reactants
Here we should reverse the first reaction and also multiply its ΔH by (- 1):
P₄O₆(s) → P₄(s) + 3O₂(g), ΔH₁' = 1640.1 kJ.
The second reaction is also reversed and also multiply its ΔH by (- 1):
P₄(s) + 5O₂(g) → P₄O₁₀(s), ΔH₂' = - 2940.1 kJ.
If we add the two reactions after modification, we get:
P₄O₆(s) → P₄O₁₀(s).
Therefore, ΔH = ΔH₁' + ΔH₂' = 1640.1 kJ + (- 2940.1 kJ) = - 1300 kJ.
Thus the correct option is B.
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Which of the following is an exothermic reaction?
a solid to a liquid
a gas change to a liquid
a liquid to a gas
a solid to a gas
Answer:
liquid to gas
Explanation:
when boiling water when evaporating heat is given out
someone please answer this question i will mark you brainliest!!
A student dissolves 15.0 g of ammonium chloride(NH4Cl) in 250. 0 g of water in a well-insulated open cup. She then observes the temperature of the water fall from 20.0 oC to 16.0 oC over the course of minutes. Use this data, and any information you need from the ALEKS Data resource, to answer the questions below about this reaction:
NH4Cl(s) rightarrow NH4+(aq) + Cl-(aq)
You can make any reasonable assumptions about the physical properties of the solution. Note for advanced students: it's possible the student did not do the experiment carefully, and the values you calculate may not be the same as the known and published values for this reaction.
1. Is this reaction exothermic, endothermic, or neither?
2. If you said the reaction was exothermic or endothermic, calculate the amount of heat that was released or absorbed by the reaction in this case.
3. Calculate the reaction enthalpy deltaHrxn per mole of NH4CI.
Answer:
1) Endothermic.
2) [tex]Q_{rxn}=4435.04J[/tex]
3) [tex]\Delta _rH=15.8kJ/mol[/tex]
Explanation:
Hello there!
1) In this case, for these calorimetry problems, we can realize that since the temperature decreases the reaction is endothermic because it is absorbing heat from the solution, that is why the temperature goes from 22.00 °C to 16.0°C.
2) Now, for the total heat released by the reaction, we first need to assume that all of it is released by the solution since it is possible to assume that the calorimeter is perfectly isolated. In such a way, it is also valid to assume that the specific heat of the solution is 4.184 J/(g°C) as it is mostly water, therefore, the heat released by the reaction is:
[tex]Q_{rxn}=-(15.0g+250.0g)*4.184\frac{J}{g\°C}(16.0-20.0)\°C\\\\ Q_{rxn}=4435.04J[/tex]
3) Finally, since the enthalpy of reaction is calculated by dividing the heat released by the reaction over the moles of the solute, in this case NH4Cl, we proceed as follows:
[tex]\Delta _rH=\frac{ Q_{rxn}}{n}\\\\\Delta _rH= \frac{ 4435.04J}{15.0g*\frac{1mol}{53.49g} } *\frac{1kJ}{1000J} \\\\\Delta _rH=15.8kJ/mol[/tex]
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Best regards!
why phenol is more acid than alcohol????
Answer:
Phenol is more acidic than alcohol due to resonance stabilization of the phenoxide ion.
which is the most fluorescent molecule?
The change in time for the first quarter is
seconds.
The change in time for the second quarte 1.39
seconds.
2.07
The change in time for the third quarter is
2.18
seconds.
The change in time for the fourth quarter is
second
Answer: The change in time for the first quarter is 1.39 seconds.
The change in time for the second quarter is 0.78 seconds.
The change in time for the third quarter is 0.64 seconds.
The change in time for the fourth quarter is 0.54 seconds.
Explanation: took info from my data and completed lab
Step 5: Measure the Speed of the Toy Car on the Higher Track
Calculate the change in time for each quarter of the track. Record the change in time in Table E of your Student Guide.
Also added the other calculations -
Calculate the average time the car took to reach each checkpoint. Record the average time in Table D of your Student Guide.
The average time to the first quarter checkpoint is 1.39 seconds.
The average time to the second quarter checkpoint is 2.18 seconds.
The average time to the third quarter checkpoint is 2.82 seconds.
The average time to the finish line is 3.36 seconds.
Calculate the speed of the car at each checkpoint by dividing the distance between each checkpoint, in meters, by the change in time. Record your answers in Table E of your Student Guide.
The speed at the first quarter checkpoint is 1.09 m/s.
The speed at the second quarter checkpoint is 1.95 m/s.
The speed at the third quarter checkpoint is 2.37 m/s.
The speed at the finish line is 2.80 m/s.
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From an element's location in the periodic table, you can predict
A. its properties.
B. its chemical name.
C. its chemical symbol.
D. when it was discovered.
Answer:
A. It's properties
Explanation:
If 50.0 g of silicon dioxide is heated with an excess of carbon, 27.9 g of silicon carbide is produced. What is the percent yield of the reaction
Answer: The percent yield of the reaction is 83.5 %
Explanation:
The given balanced equation is
[tex]SiO_2+3C\rightarrow SiC+2CO[/tex]
[tex]SiO_2[/tex] is the limiting reagent as it limits the formation of product and [tex]C[/tex] is the excess reagent.
According to stoichiometry :
60.08 g of [tex]SiO_2[/tex] produce = 40.11 of [tex]SiC[/tex]
Thus 50.0 of [tex]SiO_2[/tex] will produce=[tex]\frac{40.11}{60.08}\times 50.0=33.4[/tex] of [tex]SiC[/tex]
Experimental yield of SiC = 27.9 g
Percent yield = [tex]\frac{\text {Experimental yield}}{\text {theoretical yield}}\times 100=\frac{27.9g}{33.4g}\times 100=83.5\%[/tex]
Thus percent yield of the reaction is 83.5 %
The percent yield of 83.5 % of 50.0 g of silicon dioxide is heated with an excess of carbon, and 27.9 g of silicon carbide is produced in the reaction.
What is the chemical balance of the equation?
The chemical equations are balanced when the reactants react to form products. The reactants and products react in proper ratios and if they are not in ratio then we balance them by adding the required quantity in the reactants and the products.
The given balanced equation is
[tex]\rm SiO_2+3C---- > SiC+2CO[/tex]
[tex]SiO_2[/tex] is the limiting reagent as it limits the formation of product and is the excess reagent.
According to stoichiometry
60.08 g [tex]SiO_2[/tex] of produce = 40.11 of [tex]SiC[/tex]
Thus 50.0 of [tex]SiO_2[/tex] will produce= [tex]\dfrac{40.11}{60.08} \times 50=33.4\ SiC[/tex]
The experimental yield of SiC = 27.9 g
The percentage yield will be calculated as
[tex]\rm Percentage \ Yield = \frac{Experimental\ yield}{Theoretical \ yield }\times 100[/tex]
[tex]\rm Percentage \ yield =\dfrac{27.9}{33.49} \times 100=83.5[/tex]
Thus the percent yield of 83.5 % of 50.0 g of silicon dioxide is heated with an excess of carbon, and 27.9 g of silicon carbide is produced in the reaction.
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Calculate the molality of a solution containing 15.0 g of ethylene glycol (C2H6O2) dissolved in 145 g of water.
Answer:
Molarity=moles of solute/ L of solution
Molality = moles of solute/ kg of solvent
Solute= what is being dissolved
Solvent= what is doing the dissolving
Solution= both together
Explanation:
Example's:
#1. For number one you use the Molarity formula. M= moles of solute/ L of solution.
To find moles of Mg(NO3)2 you divide 95g by its molar mass which is 148.33g so 95/148.33=.6405 moles of Mg(NO3)2. Then plug in what you have. .38M= .6405 moles Mg(NO3)2 / X. Then solve for X using algebra. .6405/.38= 1.686 L of solution. (Volume).
Final Answer: 1.686 L
#2. For number 2 you use the Molality formula. m= moles of solute/ kg of solvent.
First you have to find moles of glucose by taking 267g and dividing it by its molar mass which is 180.56g. 267g/180.56g= 1.532 moles of glucose. Then you have to change L to kg. The easiest way to do this is to look at the density and see that for every 1 ml there is 1 gram. So to take Liters to ml you multiply 1.59 by 1000 and get 1590 ml. So that means you have 1590 grams. then you divide 1590grams by 1000 to get 1.59 Kg of slovent. Then plug in your information into the formula. molality= 1.532 moles of glucose / 1.59 Kg of solvent= .964 molality.
Final answer: .964 mol/Kg
#3. m= moles of solute / Kg of solvent. 0.445 mol solute / 2.07 Kg solvent= .215 Molality
Final Answer: .215 mol/Kg
#4. m= moles of solute / Kg of solvent. take 13.5g and divide it by ethylene glycols molar mass which is 62.068 g. 13.5g / 62.068g= .218 mol. Then you take 135g of water and divide it by 1000 to get Kg. 135/1000=.135 Kg. Then plug in your information. m= .218mol/.135 Kg= 1.615 molality
Final Answer: 1.615 mol/Kg.
Which of these actions precedes a precipitation event
A: clouds form
B: the air gets colder
C: the wind picks up speed
D: Raindrops are supercooled
Answer:
C. The wind picks up speed
Explanation:
Im not sure but i hope im correct
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Heat is most closely related to which kind of energy?
Answer:
I'm very sure it's thermal energy.
Explanation:
Answer:
thermal energy is the answer
Where are electrons found in an atom?
Answer:
outside the nucleus
Explanation:
When 0.20 mol of hydrogen gas and 0.15 mol of iodine gas are heated at 450 °C until equilibrium is established, the equilibrium mixture is found to contain 0.26 mol of hydrogen iodide. The equation for the reaction is as follows
H2((g) + I2(g) ⇋ 2HI(g)
What is the correct expression for the equilibrium constant, Kc?
Answer:
[tex]Kc=\frac{[HI]^2}{[I_2][H_2]}[/tex]
Explanation:
Hello there!
In this case, for these equilibrium problems it is firstly necessary to know the balanced reaction at equilibrium:
H2((g) + I2(g) ⇋ 2HI(g)
Next, by means of the law of mass action, it turns out possible for us to write the required and correct expression for the equilibrium constant by considering the concentrations and the coefficients in the aforementioned reaction:
[tex]Kc=\frac{[HI]^2}{[I_2][H_2]}[/tex]
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2.85 x 10-3 moles of an unknown compound has a mass of 0.206 g. The compound could be:
Answer:
Calcium sulfide (CaS)
Explanation:
From the question
Number of mole (n) = reacting mass (R)/molar mass (m)
n = R/m.................... Equation 1
make m the subject of the equation
m = R/n...................... Equation 2
Given: R = 0.206, n = 0.00285 moles.
Substitute these values into equation 2
m = 0.206/(0.00285)
m = 72.3 g/mol
From the above, the compond with molar mass close to 72.3 g/mol is Calcium sulfide (CaS)
. Give an example of a salt that is less soluble when the temperature increases
Answer:
cerium (iii) sulfate is less soluble
Answer:
cerium sulphate is less solube when the temperature increase
These properties best describe which body (Gases Surface, 75%H, 25% He, Zones)
(18 Points)
Planet
or
Sun
NO LINKS
Answer:sun
Explanation:The Sun is the star at the center of the Solar System. It is a nearly perfect sphere of hot plasma, heated to incandescence by ... When hydrogen fusion in its core has diminished to the point at which the Sun is no longer in . Sunlight on the surface of Earth is attenuated by Earth's atmosphere, so that less power arrives
what do you mean by carrier
Answer:
1 : one that carries : bearer, messenger. 2a : an individual or organization engaged in transporting passengers or goods for hire. b : a transportation line carrying mail between post offices.
Choose the options below that are true.
A. The rate law for a given reaction can be determined from a knowledge of the rate-determining step in that reaction's mechanism.
B. The rate laws of all chemical reactions can be determined directly from their net chemical equations.
C. The rate laws of bimolecular elementary reactions are second order overall.
D. The rate law for a given reaction can be determined from its reaction mechanism, without the accompanying rates of each elementary step in the mechanism.
Answer:
The options (A) -The rate law for a given reaction can be determined from a knowledge of the rate-determining step in that reaction's mechanism. and (C) -The rate laws of bimolecular elementary reactions are second order overall ,is true.
Explanation:
(A) -The rate law can only be calculated from the reaction's slowest or rate-determining phase, according to the first sentence.
(B) -The second statement is not entirely right, since we cannot evaluate an accurate rate law by simply looking at the net equation. It must be decided by experimentation.
(C) -Since there are two reactants, the third statement is correct: most bimolecular reactions are second order overall.
(D)-The fourth argument is incorrect. We must track the rates of and elementary phase that is following the reaction in order to determine the rate.
Therefore , the first and third statement is true.
Calculate the pH of a 0.75 M solution of H2SO4.
Answer:
न्द्न्द्ज्द्ज्फ्ज्फ्ज
Calculate the moles of Iron (III) Sulfide (Fe253) in 218.8 grams. The molar mass of Iron (III) Sulfide is 207.90 g/mol. Do not include units in your response.
Answer:
1.052
Explanation:
In order to convert from grams of a substance to moles, we need to divide the given mass by the molar mass of the substance:
Moles = Mass / Molar MassAll the required data is given by the problem:
Moles = 218.8 g / 207.90 g/mol = 1.052 molesThere are 1.052 moles in 218.8 grams of iron (III) sulfide.