Answer:
to remove any remaining 2,4-dinitrophenylhydrazone
Explanation:
Usually, when an organic compound is synthesised, traces of impurities such as excess reagents or solvent remain in the product.
It is therefore imperative that these contaminants are removed so that the product can attain a very high degree of purity.
Hence, during the synthesis of 2,4-dinitrophenylhydrazone derivative, 10 mL of 2 M hydrochloric acid is titrated against the crude product so that any remaining 2,4-dinitrophenylhydrazone is removed.
Gaseous ethane (CH,CH,) will react with gaseous oxygen (02) to produce gaseous carbon dioxide (CO2) and gaseous water (H,0). Suppose 4.21 g of
ethane is mixed with 31. 9 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: The mass of [tex]CO_2[/tex] produced is 12.32 g
Explanation:
The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)
For ethane:Given mass of ethane = 4.21 g
Molar mass of ethane = 30 g/mol
Putting values in equation 1, we get:
[tex]\text{Moles of ethane}=\frac{4.21g}{30g/mol}=0.140mol[/tex]
For oxygen gas:Given mass of oxygen gas = 31.9 g
Molar mass of oxygen gas= 32 g/mol
Putting values in equation 1, we get:
[tex]\text{Moles of oxygen gas}=\frac{31.9g}{32g/mol}=0.997mol[/tex]
The chemical equation for the combustion of ethane follows:
[tex]2C_2H_6+7O_2\rightarrow 4CO_2+6H_2O[/tex]
By stoichiometry of the reaction:
If 2 moles of ethane reacts with 7 moles of oxygen gas
So, 0.140 moles of ethane will react with = [tex]\frac{7}{2}\times 0.140=0.49mol[/tex] of oxygen gas
As the given amount of oxygen gas is more than the required amount. Thus, it is present in excess and is considered as an excess reagent.
Thus, ethane is considered a limiting reagent because it limits the formation of the product.
By the stoichiometry of the reaction:
If 2 moles of ethane produces 4 moles of [tex]CO_2[/tex]
So, 0.140 moles of ethane will produce = [tex]\frac{4}{2}\times 0.140=0.28mol[/tex] of [tex]CO_2[/tex]
We know, molar mass of [tex]CO_2[/tex] = 44 g/mol
Putting values in above equation, we get:
[tex]\text{Mass of }CO_2=(0.28mol\times 44g/mol)=12.32g[/tex]
Hence, the mass of [tex]CO_2[/tex] produced is 12.32 g
The rate equation for a reaction between substances C and D is:
rate = k[C]^2 [D]^2
The initial rate is found to be 7.5 x 10^-3mol dm^-3s^-1when the initial concentration of
C is of 0.25 mol dm^-3and the initial concentration of D is 0.50 mol dm^-3.
Calculate the value of the rate constant, k, at this temperature and deduce its units.
*Important Asap please *
Answer:
[tex]rate = k[C] {}^{2} [D] {}^{2} \\ 7.5 \times {10}^{ - 3} = k {(0.25)}^{2} {(0.50)}^{2} \\ k = \frac{7.5 \times {10}^{ - 3} }{ {(0.25)}^{2} {(0.50)}^{2} } \\ k = 0.48 \: {mol}^{ - 3} {dm}^{9} {s}^{ - 1} [/tex]
A solution of which of the following coordination compounds will form a precipitate when treated with aqueous AgNO3?
a. [Cr(NH3)3C13]
b. All will form a precipitate
c. Na3[Cr(CN)6]
d. Na3[CrCl6]
e. [Cr(NH3)6.]C13
Answer:
[Cr(NH3)6.]C13
Explanation:
Alfred Werner's coordination theory (1893) recognized two kinds of valency;
Primary valency which are nondirectional and secondary valency which are directional.
Hence, the number of counter ions precipitated from a complex depends on the primary valency of the central metal ion in the complex.
We must note that it is only these counter ions that occur outside the coordination sphere that can be precipitated by AgNO3.
If we consider the options carefully, only [Cr(NH3)6.]C13 possess counter ions outside the coordination sphere which can be precipitated when treated with aqueous AgNO3.
15.4 g of methanol (CH3OH) reacts completely according to the following reaction:
CH3OH (g) → CH2O (g) + H2 (g)
If 12.35 g of formaldehyde (CH2O) is produced, what is the percent yield for this reaction?
Explanation:
hope the working on picture helps :)
93.5 is the percent yield for this reaction.
What is a theoretical yield?The theoretical yield is the maximum possible mass of a product that can be made in a chemical reaction.
Step 1: Solve for the mass of CH_2O produced.
Mass [tex]CH_2O[/tex] = 15.4 g [tex]CH_3OH[/tex] × (1 mol [tex]CH_3OH[/tex] ÷ 32.04 g [tex]CH_3OH[/tex]) × (1 mol [tex]CH_2O[/tex] ÷ 1 mol [tex]CH_3OH[/tex]) × (30.03 g [tex]CH_2O[/tex] ÷ 1 mol [tex]CH_2O[/tex])
Mass [tex]CH_2O[/tex]= 14.43 g
Step 2: Determine the theoretical yield.
Theoretical yield = mass [tex]CH_2O[/tex]
Theoretical yield = 14.43 g
Step 3: Solve for the percent yield.
Percent yield = (actual yield ÷ theoretical yield) × 100
Percent yield = (13.5 g ÷ 14.43 g) × 100
Percent yield = 0.9355509356 × 100 =93.5 percent
Hence, 93.5 is the percent yield for this reaction.
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You have 4 litres of a 3.0 mol/L solution of NaCl in a
chemical store room.
How many moles of NaCl are present? *
0.75 mol
1.33 mol
12 mol
M = 3.0 mol/L
V = 4 L
Required:n
Solution:M = n / V
n = MV
n = (3.0 mol/L)(4 L)
n = 12 mol
Therefore, the number of moles of NaCl present is 12 mol.
#ILoveChemistry
#ILoveYouShaina
Answer 12 mol
Explanation: [tex]C_{M} = \frac{n}{V} ==> n = C_{M} *V=4*3=12 mol[/tex]
how many hydrogen atoms are in one mole of caffeine
[tex] \huge \mathbb{ HI !!}[/tex]
My Answer 10My ExplanationAlthough caffeine (a stimulant found in coffee and tea) is a relatively complicated molecule, it's only eight atoms of carbon, ten of hydrogen, four of nitrogen and two of oxygen – C8H10N4O2. This kind of representation is called a molecular formula – it tells us what kind of atoms we have, and how many of each.
#CarryOnLearningThere are 10 hydrogen atoms in one mole of caffeine.
What is caffeine?Caffeine belongs to the methylxanthine category of nervous system stimulants. It's just a cognitive booster that improves alertness but also attentional performance.
Caffeine's chemical formula would be C8H10N4O2, that indicates it contains eight carbon atoms, ten hydrogen atoms, four nitrogen atoms, and two oxygen atoms.
So it can be seen that , 10 hydrogen resent in caffeine molecule.
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38. Consider the following equilibrium:
2CO(g) + O2(g) =2CO2
Keg=4.0 x 10-10
What is the value of Key for 2CO2(g) + 2COR + O2g) ?
Answer:
[tex]Key=2.5x10^{-9}[/tex]
Explanation:
Hello there!
In this case, according to the given information, it turns out possible for us to calculate the equilibrium constant value for the reverse reaction:
[tex]2CO_2(g) \rightleftharpoons 2CO(g) + O_2(g)[/tex]
By knowing that the equilibrium expression is actually:
[tex]Key =\frac{[CO]^2[O_2]}{[CO_2]^2} =\frac{1}{Keg}[/tex]
Thus, we plug in and solve for the inverse of Keq to obtain Key as follows:
[tex]Key =\frac{1}{4.0x10^{-10}}\\\\Key=2.5x10^{-9}[/tex]
Regards!
How much energy is used when 14.3 moles of hydrosulfuric acid reacts with 17.1 moles
of oxygen?
2 H2S + 3 02 + 175 KJ
—->2 SO2 + 2 H20
Which substance is the limiting reactant?
Answer:
O2 is the limiting reactant.
Explanation:
Hello there!
In this case, according to the given information about this reaction, one could identify the limiting reactant by performing a mole ratio of H2S to SO2 and O2 to SO2:
[tex]14.3molH_2S*\frac{2molSO_2}{2molH_2S}=14.3molSO_2 \\\\17.1molO_2*\frac{2molSO_2}{3molO_2}=11.4molSO_2[/tex]
Thus, since 17.1 moles of O2 yields fewer moles than 14.3 moles of H2S, we infer the former is the limiting reactant.
Regards!
A pressure cooker contains 5.68 L of air at a temperature of 390 4K if the absolute pressure of the air in the pressure cooker is 205 Pa how many moles of air are in the cooker
Answer:
3.59x10⁻⁴ mol
Explanation:
Assuming ideal behaviour we can solve this problem by using the PV=nRT formula, where:
P = 205 PaV = 5.68 Ln = ?R = 8314.46 Pa·L·mol⁻¹·K⁻¹T = 390.4 KWe input the data given by the problem:
205 Pa * 5.68 L = n * 8314.46 Pa·L·mol⁻¹·K⁻¹ * 390.4 KAnd solve for n:
n = 3.59x10⁻⁴ molHELPP
There are 9.23 x 1023 molecules of water in a beaker, how many moles are there?
Answer:
Answer: There are 1.53 moles present in molecules of water in a beaker.
Explanation:
According to the mole concept, there are molecules present in 1 mole of a substance.
So, number of moles present in molecules are calculated as follows.
Thus, we can conclude that there are 1.53 moles present in molecules of water in a beaker.
Explanation:
Will mark Brainlest ( molecular weight of ammonium sulphate)
step by step
Answer:
132 amu
Explanation:
ammonium sulphate is [tex](NH_4)_{2} SO_4[/tex]
to calculate molecular weight we need
atomic weight of the element of the compound
here ammonium sulphate is formed by two elements
2 nitrogen , 8 hydrogen , 1 sulphur amd 4 oxygen
atonomic number of nirogen is 14 , hydrogen is 1 , sulphur has 32 and oxygen has 16
so lets calculate molecular weight of ammonium sulphate
2*14 + 8*1 + 1*32 + 4*16
28 + 8 + 32 + 64
132 amu
Which molecule is pentanoic acid?
ОА.
Н
1
НЕС-ОН
ОВ.
Н
ОН
ор.н.н
Answer:
PubChem CID 7991
Structure Find Similar Structures
Chemical Safety Laboratory Chemical Safety Summary (LCSS) Datasheet
Molecular Formula C5H10O2 or CH3(CH2)3COOH
Synonyms Valeric acid PENTANOIC ACID n-Valeric acid 109-52-4 n-Pentanoic acid More.
define molecular formula?
A molecular formula is an expression that states the number and type of atoms present in a molecule of a substance.
Example : H2O (water) There are 2 atoms of Hydrogen and 1 atom of Oxygen in this substance
Use the periodic table to determine the electron configuration for aluminum (Al) and arsenic (As) in noble-gas notation.
Al:
Explanation:
2,8,3don't know .............
.....how
Hexane, C6H14, is a(n)
hydrocarbon.
Saturated or Unsaturated
Answer:
Like any compound ending in '-ane', hexane is an alkane. It is commonly referred to as n-hexane and classified as a saturated hydrocarbon
Answer:
its saturated
cus its like
CnH2n+2
NaOH is an Arrhenius base because it increases the concentration of hydroxide ions when dissolved in solution. (3 points) True False
When NaOH is an Arrhenius base so it is dissociated in water so the given statement is false.
NaOH is an Arrhenius base:It is this base since it dissociates in water to provide the hydroxide (OH-) and sodium (Na+) ions.
It is the substance that is ionized at the time when it is dissolved in water to provide the hydrogen ion.
hence, the given statement is false.
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Answer:
true
Explanation:
i took the test and got it right the other guy is wrong
The reaction of 9.50 g of carbon with Excess O2 Yield 12.8 of CO2. What is the percent yield of this reaction?
Answer:
Percentage yield = 36.75%
Explanation:
We'll begin by writing the balanced equation for the reaction. This is illustrated below:
C + O₂ —> CO₂
Next, we shall determine the mass of C that reacted and the mass of CO₂ produced from the balanced equation. This can be obtained as follow:
Molar mass of C = 12 g/mol
Mass of C from the balanced equation = 1 × 12 = 13 g
Molar mass of CO₂ = 12 + (2×16)
= 12 + 32
= 44 g/mol
Mass of CO₂ from the balanced equation = 1 × 44 = 44 g
SUMMARY:
From the balanced equation above,
12 g of C reacted to produce 44 g of CO₂.
Next, we shall determine the theoretical yield of CO₂. This can be obtained as follow:
From the balanced equation above,
12 g of C reacted to produce 44 g of CO₂.
Therefore, 9.50 g of C will react to produce = (9.50 × 44) / 12 = 34.83 g of CO₂.
Thus, the theoretical yield of CO₂ is 34.83 g.
Finally, we shall determine the percentage yield of the reaction. This can be obtained as follow:
Actual yield of CO₂ = 12.8
Theoretical yield of CO₂ = 34.83 g
Percentage yield =?
Percentage yield = Actual yield / Theoretical yield × 100
Percentage yield = 12.8 / 34.83 × 100
Percentage yield = 1280 / 34.83
Percentage yield = 36.75%
Write the first step of this elimination using curved arrows to show electron reorganization. Remember that a mechanism step may require more than one curved arrow.
Answer:
Explanation:
The missing image can be seen below.
From the given information:
The elimination process follows E2 mechanism which is a 2nd order kinetics.
At E2 mechanism, the base attaches with the beta hydrogen while also removing the leaving group in the same process. In the given compound 2-chloro-2-methylpropane, chloride is the leaving group that results in the product; 2-methylprop-1-ene.
The mechanism is seen in the second image,
What determines the ending units of a stoichiometry problem?
Answer:
1.Write the balanced chemical equation.
2.Convert the units of the given substance (A) to moles.
3.Use the mole ratio to calculate the moles of wanted substance (B).
4.Convert moles of the wanted substance to the desired units.
Explanation:
Which is most likely the first step in a basic food chain?
1. The snake obtain energy by eating the mouse
2. Plants make energy-rich food using sunlight
3. The hawk obtains energy by eating the snake
4. The sun emits energy.
Answer:
4
Explanation:
why hydride ion is strong base than hydroxide ion?
Answer:
The hydride ion,H−is a stronger base, so it will abstract a proton from the water. As the water will give protons, so water will work as an acid and an acid-base reaction will take place. Hydride ions get protons from water and form hydrogen gas and hydroxide ions.
Sodium hydride is the chemical compound with the empirical formula NaH. This alkali metal hydride is primarily used as a strong yet combustible base in organic synthesis. NaH is a saline (salt-like) hydride, composed of Na+ and H− ions, in contrast to molecular hydrides such as borane, methane, ammonia, and water.
21.5g of sodium chloride dissolves in 60g of water at25C. Calculate the concentration of the solution.
Which of the following explains the high boiling
point of water?
a Surface tension
b Polarity
C Capillary action
d Hydrogen bonding
Answer:
The correct answer is - d. hydrogen bonding.
Explanation:
Water has strong hydrogen bonds between its molecules that require a very high amount of energy in order to break. Water molecules are joined together or bound with a strong intermolecular force called hydrogen bonds.
These bonds require more kinetic energy which means more temperature or heat in order to break the bonds and turn into steam and this is the reason it has a high boiling point.
How much work (in J) is involved in a chemical reaction if the volume decreases from 4.35 to 1.20 L against a constant pressure of 0.822 atm?
Express your answer to three significant figures and include the appropriate units.
Answer:
W = -262 J.
Explanation:
Hello there!
In this case, according to the given information, we can recall the definition of work in terms of constant pressure and variable volume as follows:
[tex]W=P(V_2-V_1)[/tex]
So we plug in the given pressure and volumes to obtain:
[tex]W=0.822atm(1.20L-4.35L)\\\\W=-2.60atm*L[/tex]
Now, we convert this number to J (Pa*m³) by using the shown below conversion factor:
[tex]W=-2.60atm*L*\frac{101325Pa}{1atm} *\frac{1m^3}{1000L}\\\\W=-262J[/tex]
Regards!
What is the colour of red cabbage in vinegar?
Answer:
When red cabbage is treated with an acid or a base, it produces anthocyanin, a water-soluble pigment that changes color. In acidic situations with a pH less than 7, the pigment turns red, whereas in alkaline (basic) situations with a pH more than 7, the pigment turns bluish-green.
Explanation:
3. Available energy increases as it is transferred from one organism to another in food chain.
True or false
Answer:
False
Explanation:
Gets used by other animals.
Write a summary of the science of muscle growth?
Answer:Muscle growth or “skeletal muscle hypertrophy,” as it's called at science parties) is the result of a complex process that adds more myosin “filaments” to each muscle fiber. This makes the “engine” of the cell bigger and stronger over time. ... This process is called muscle protein synthesis, or MPS. Skeletal muscle is composed of thread-like myofibrils and sarcomeres that form a muscle fiber and are the basic units of contraction. The 650 skeletal muscles in the human body contract when they receive signals from motor neurons, which are triggered from a part of the cell called the sarcoplasmic reticulum.
Imagine that one night on the news, you saw a report that chemists had discovered a medicine to cure cancer. Would you believe that this report was true? What questions would you want to see answered in the report to help you make your decision? Answer in two to three paragraphs.
Answer:
Yes I would believe that this report was true, because nobody would lie on a news channel that they cured cancer and then not cure it. That would completely ruin their credibility as well as the news channels credibility. So no news channel would take the story if it was made up.
I would like to see there studies on how the medicine kills off the cancer and the side effects of the medicine on the human body. I would want to know how the medicine is made, if its FDA approved, and how the medicine will be distributed across the globe and at what prices, as well as how easily the medicine expires.
Answer:
Explanation:
I will probably believe the report but want to find out more details. First is cure for which cancer has been found. Cancer is a general name for a large family of different diseases. So it is very likely that the cure is for some specific cancers.
Secondly I want to know if the cure has any side effect. The typical treatments for cancer now are radiation and chemo therapy. Both can cause serious side effects.
Lastly the cost of cure is important. New drugs with patent protection can be very expensive which limit on how many people can afford the treatment.
what are the characteristics of primary standard substances?
Answer:
the characteristics of primary standard substances are:
1.High purity.
2.Stability (low reactivity)
3.Low hygroscopicity
4.High equivalent weight
5.Non-toxicity.
Ready and cheap availability.
What volume of 6.49 MHCl is needed to prepare 2.11 L of 1.07 MHCl? Your answer should have three significant figures.
Answer:
0.348 L
Explanation:
Step 1: Given data
Concentration of the concentrated solution (C₁): 6.49 MVolume of the concentrated solution (V₁): ?Concentration of the dilute solution (C₂): 1.07 MVolume of the dilute solution (V₂): 2.11 LStep 2: Calculate the volume of the concentrated solution
We want to prepare a dilute solution from a concentrated one. We can calculate the volume of the concentrated solution using the dilution rule.
C₁ × V₁ = C₂ × V₂
V₁ = C₂ × V₂ / C₁
V₁ = 1.07 M × 2.11 L / 6.49 M = 0.348 L