The Biuret test is a simple and quick method to detect proteins in a sample, and a positive result is indicated by a color change from blue to violet or purple. The correct answer is proteins.
Biuret reagent is used to test for the presence of proteins in a sample. The Biuret test is a chemical test used to detect the presence of peptide bonds in proteins and peptides. When Biuret reagent, which contains copper(II) ions, is added to a solution containing proteins, the copper(II) ions react with the nitrogen and oxygen atoms in the peptide bonds to form a violet or purple-colored complex. This color change indicates the presence of proteins.
The Biuret reaction is not specific to proteins; it can also react with compounds that contain two or more peptide bonds. However, it is most commonly used to detect proteins in biological samples. The test is not quantitative, but it can give a rough estimate of the amount of protein present based on the intensity of the color change.
The Biuret reagent typically consists of a solution of potassium hydroxide (KOH) and copper(II) sulfate (CuSOâ‚„). The alkaline solution (KOH) denatures the proteins, exposing the peptide bonds, and the copper(II) ions form the characteristic colored complex with the peptide bonds.
In summary, the Biuret test is a simple and quick method to detect proteins in a sample, and a positive result is indicated by a color change from blue to violet or purple.
Rank the homologous series for a set of alkanes by their boiling point? The boiling points for a set of compounds in a homologous series can be qualitatively predicted using intermolecular force strengths. Using their condensed structural formulas, rank the homologous series for a set of alkanes by their boiling point.
Rank these alkanes from highest to lowest boiling points
1....; The correct answer is heptane 3,3-dimethylpentane hexane butane. Thanks though, your tip helped!
Alkanes from highest to lowest boiling points:
1. heptane2. 3.3 dimethyl pentane3. hexane4. butaneFurther explanationAlkanes are saturated hydrocarbons with all carbon bonds being single bonds
General formula:
[tex]\large{\boxed {\bold {C_nH_{2n + 2}}}[/tex]
There are several rules for naming alkanes from IUPAC:
the name of the branch followed by the name of the main chain the main chain is the longest chain that has the most branches branches are given the name alkyl with the symbol -R, and begin with a number, with the position of the branch getting the smallest number more than one branch is prefixed in, tri, tetra, penta, etc. and in alphabetical order with the smallest number.In determining the alkane boiling point, if in the same homologous series, then just look for alkanes with the largest relative molecular mass that will have a large boiling point too. So in an alkane in the form of a straight-chain, the more carbon atoms, the longer the main chain, the bigger the boiling point.
But if the relative molecular mass is the same, the alkanes have fewer branches will have a greater boiling point.
The more branches, the lower the boiling point, even though the number of carbon atoms is the same (as in isomers)
In isomers that have the same molecular formula and relative molecular mass, alkanes that have the fewest branches will have the largest boiling point.
So that the general determination of the alkane boiling point is (based on its priority)
1. relative molecular massthe greater the higher the boiling point
2. main chain branchthe fewer branches the higher the boiling point
The branching on the main chain in the alkane structure causes the attraction between the molecules to be lower so that to release this attractive force only requires low energy, ie at low temperatures
The relative molecular mass of each alkane in the above problem is:
1. heptane: 1002. 3.3 dimethyl pentane: 1003. hexane: 864. Butane: 58The relative molecular mass values above indicate that there are similarities in the relative molecular mass values of heptane and 3.3 dimethyl pentane. But because the unbranched chain has a higher boiling point so heptane has a greater boiling point than 3.3 dimethyl pentane
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Keywords: alkanes, main chains, branches, boiling points, relative molecular mass
What is the molecular mass of cholesterol if .00105mol wieghs .406g?
Earth is the only planet that has a _____ and a _____.
What is ionization energy?
The ionization energy is the amount of energy needed to remove a valence electron. Valence electrons are the outermost electrons.
Assume you had a silver sphere with a mass of 1.50kg. calculate the diameter of the sphere (in cm). the density of silver is 10.5 g/cm^3. the formula for the volume of a sphere is... v = 4/3 3.14 r^3
Consider three 10-g samples of water: one as ice, one as liquid, and one as vapor. how do the volumes of these three samples compare with one another?
Ice has the largest volume, followed by liquid water, and then water vapor.
Explanation:Water is one of the few substances on Earth that exists naturally in all three states: solid (ice), liquid (water), and gas (water vapor). The density of each state of water varies, with the vapor state being the least dense and the liquid state being the most dense. The solid state, which is ice, is less dense than the liquid state. So, in terms of volume, the ice sample will have the largest volume, followed by the liquid water sample, and then the water vapor sample, which will have the smallest volume.
Acids generally have an excess of ______ ions in solution, while bases usually have an excess of ______ ions in solution.
Write balanced chemical equation for the oxidation of fe2+(aq) by s2o2−6 (aq).
A combination reaction occurs when one reactant forms two or more products true or false
Answer:
its true for apex ;)
Explanation:
Petrolyn motor oil is a combination of natural oil and synthetic oil. it contains 8 liters of natural oil for every 5 liters of synthetic oil. in order to make 728 liters of petrolyn oil, how many liters of synthetic oil are needed?
If liquid a is more volatile than liquid b, which is also true? hints if liquid a is more volatile than liquid b, which is also true? liquid a has a lower vapor pressure than liquid
b. liquid a has stronger intermolecular forces than liquid
b. liquid a evaporates more slowly than liquid
b. liquid a has a lower boiling point than liquid
b.
Answer:
Liquid a has a lower boiling point than liquid b.
Explanation:
Hello,
In this case, volatility is associated with three factors:
1. Vapor pressure: this is the pressure exerted by the gas molecules in equilibrium with the liquid. The higher the vapor pressure, the higher the volatility.
2. Intermolecular forces: are the interactions attracting or repelling the material's molecules. The stronger the forces, the lower the volatility as the molecules remain strongly closer.
3. Boiling point: is the condition of both temperature and pressure at which a liquid passes from liquid to gas. The lower the boiling point, the higher the volatility as more molecules easily pass from liquid to gas.
In such a way since liquid a is more volatile than liquid b, the answer is liquid a has a lower boiling point than liquid b based on the aforesaid factors.
Best regards.
A student arranged the four cards sequentially in a row on the basis of the periods when these events occurred. The card showing the earliest event was placed on the extreme left. Which of these cards was placed third in the row?
The sequences of the geological happenings in the periodical order is called the geological time's scale. The card of the third row depicts the first flowering plant.
What is the order of the events?Events of the evolution can be explained based on the geological timelines and are arranged on the basis of their discoveries. In the question, the order of the events is arranged from the earliest to the newest.
The earliest event was the appearance of life in the sea followed by the rock formation. The third event was the appearance of the flowering plant on the land followed by land animals.
Therefore, the third card depicts the flowering land plant.
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which of the following is the most reasonable explanation for a drop in temperature of gas?
A) a decrease in the volume of the container
B) a decrease in the average kinetic energy of the gas particles
C)an increase in the average potential energy of the gas particles
D) an increase in gas pressure
Answer: The correct answer is option B.
Explanation:
Average kinetic energy of the gas molecule is given by relation:
[tex]E_K=\frac{3}{2}\frac{R}{N_A}\times T[/tex]
[tex]N_A[/tex] = Avogadro Number
T = Temperature of the gas in Kelvins.
R = Universal gas constant
[tex]E_K\propto T[/tex]
With increase in temperature the kinetic energy of the gas molecule increases and vice-versa.
So, according to the question the explanation for a drop in temperature of the gas is decrease in average kinetic energy of the gas molecules.
Hence, the correct answer is option B.
What is present in the glucose molecule that is missing in the carbon dioxide molecule?
When copper sulfate reacts with sodium hydroxide solution, a precipitate of copper hydroxide and a solution sulfate are formed
Calculate the amount of heat required to vaporize 84.8 g of water at its boiling point.
Answer: Amount of heat required to vaporize 84.8 g of water is 191.7kJ.
Explanation: We are given 84.8 grams of water, to convert it into moles, we use the formula:
[tex]Moles=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]
Molar mass of water = 18 g/mol
[tex]Moles=\frac{84.8g}{18g/mol}=4.71moles[/tex]
As we know that [tex]\Delta H_{vap}[/tex] for 1 mole of water at 100° C is 40.7 kJ/mol
So, to calculate the amount of heat required, we use the formula:
[tex]q=m\Delta H_{vap}[/tex]
Putting the values in above equation, we get
[tex]q=4.71mol\times 40.7kJ/mol[/tex]
q = 191.7kJ
if you drop a 50 gram piece of metal with a temperature of 125° Celsius into 1000 grams of water at 20° Celsius, what best describes what would occur?
What is the concentration, in grams per liter, of a solution prepared by dissolving 0.00040 mol HCl in 2.2 L H2O? Assume that the volume of the solution does not change when the HCl is added.
On Ed. the exact answer is 0.0066.
Which of the following quantum number combinations is not allowed in a ground-state atom? (7, 4, -2, -½) (3, 0, 0, +½) (2, 1, 1, -½) (3, 2, 3, +½)
An aqueous solution contains 0.050 m of methylamine, with kb = 4.4 x 10-4. what is the percent ionization and the ph of the solution?
Final answer:
To calculate the hydroxide ion concentration and the percent ionization of a 0.0325-M solution of ammonia, use the Kb expression and an ice table. The hydroxide ion concentration is 7.6 x 10-4 M and the percent ionization is 2.34%.
Explanation:
To calculate the hydroxide ion concentration and the percent ionization of a 0.0325-M solution of ammonia, we can use the formula for Kb. Kb is the equilibrium constant for the reaction of NH3 with water to form NH4+ and OH-. The equation is: NH3 + H2O ⇌ NH4+ + OH-. The Kb value for ammonia is given as 1.76 x 10-5.
First, we need to calculate the hydroxide ion concentration. We can use the Kb expression to set up an ice table and solve for the OH- concentration. Let x be the concentration of OH-. Since the initial concentration of NH3 is 0.0325 M, the initial concentration of OH- is 0 M.Using the Kb expression, we can set up the equation: Kb = (x)(x)/(0.0325 - x). Solving for x gives us x = 7.6 x 10-4 M. Therefore, the hydroxide ion concentration is 7.6 x 10-4 M.To calculate the percent ionization, we can use the formula: % ionization = (OH- concentration / initial ammonia concentration) x 100. Plugging in the values, we get % ionization = (7.6 x 10-4 / 0.0325) x 100 = 2.34%.Which laws can be combined to form the ideal gas law?
Boyle’s law and Charles’s law
Gay-Lussac’s law and Avogadro’s law
Charles’s law, Avogadro’s law, and Boyle’s law
Dalton’s law, Gay-Lussac’s law, and Avogadro’s law
Charles’s law, Avogadro’s law, and Boyle’s law can be combined to form the ideal gas law.
What is Boyle's law?
Boyle's law is an experimental gas law which describes how the pressure of the gas decreases as the volume increases. It's statement can be stated as, the absolute pressure which is exerted by a given mass of an ideal gas is inversely proportional to its volume provided temperature and amount of gas remains unchanged.
Mathematically, it can be stated as,
P∝1/V or PV=K. The equation states that the product of of pressure and volume is constant for a given mass of gas and the equation holds true as long as temperature is maintained constant.
According to the equation the unknown pressure and volume of any one gas can be determined if two gases are to be considered.That is,
P₁V₁=P₂V₂
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What type of bond is easily disrupted in aqueous solutions?
A solution of sucrose in water has a boiling point that is _____ 100°C.
Which drawing depicts the electron configuration of nitrogen?
At 25 °c only 0.0420 mol of the generic salt ab2 is soluble in 1.00 l of water. what is the ksp of the salt at 25 °c?
The Ksp, or solubility product constant, of a generic salt AB₂ at 25 °C with a solubility of 0.0420 mol/L is 2.96 × 10⁻⁴.
The student has asked to find out the Ksp of a generic salt AB₂ at 25 °C, when its solubility is given.
The solubility product constant (Ksp) is the equilibrium constant for the dissolution of a solid substance into an aqueous solution. Considering the stoichiometry of the generic salt AB₂, when it dissolves in water, it dissociates into one A²⁺ ion and two B⁻ ions.
The solubility equilibrium reaction is:
AB₂(s) → A²⁺(aq) + 2B⁻(aq)
Since the solubility is 0.0420 mol/L for AB₂, the concentration of A²⁺ will be 0.0420 M and the concentration of B⁻ will be 2 × (0.0420) M = 0.0840 M in the solution.
Using the expression for Ksp:
Ksp = [A²⁺][B⁻]² = (0.0420)×(0.0840)²
We calculate Ksp:
Ksp = (0.0420)×(0.007056) = 2.96 × 10⁻⁴
Thus the Ksp for AB₂ at 25 °C is 2.96 × 10⁻⁴.
According to Charles law, which two quantities are directly proportional?
A.) time and pressure
B.) volume and pressure
C.) volume and temperature
D.) pressure and temperature
During an effusion experiment, oxygen gas passed through a tiny hole 2.5 times faster than the same number of moles of another gas under the same conditions. What is the molar mass of the unknown gas? (Note: the molar mass of oxygen gas is 32.0 g/mol.)
Answer:
2.0 x 10^2g
Explanation:
If you reacted 88.9 g of ammonia with excess oxygen, what mass of nitric oxide would you expect to make? You will need to balance the equation first. NH3(g) + O2(g) -> NO(g) + H2O(g)
Final answer:
The mass of nitric oxide expected to be produced from reacting 88.9 g of ammonia with excess oxygen is 156.7 g after balancing the chemical equation and performing stoichiometry calculations.
Explanation:
Calculating Mass of Nitric Oxide Produced from Ammonia:
To find the mass of nitric oxide that can be produced from reacting 88.9 g of ammonia with excess oxygen, first we need to balance the chemical equation. The balanced equation is:
4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(g)
Next, we use the molar mass of ammonia (NH3) which is 17.03 g/mol to convert 88.9 g of NH3 to moles:
88.9 g NH3 ÷ 17.03 g/mol = 5.22 moles of NH3
Since the balanced equation shows that 4 moles of NH3 produce 4 moles of NO, we can calculate the moles of NO produced from 5.22 moles of NH3:
(5.22 moles NH3) × (4 moles NO / 4 moles NH3) = 5.22 moles NO
Finally, using the molar mass of NO (30.01 g/mol), we find the mass of NO produced:
(5.22 moles NO) × (30.01 g/mol) = 156.7 g NO
Therefore, we expect to make 156.7 g of nitric oxide from the reaction of 88.9 g of ammonia with excess oxygen.
How many moles of libr are contained in 347 g of water in a 0.175 m libr solution?
Answer:
Molaridad = número de lunares de soluto/Kg de disolvente
La molaridad se da en el problema como 0,175 m
Masa de disolvente = 347 gm = 0,347 Kg
por lo tanto
0.175 = número de lunares de LiBr / 0.347
número de lunares de LiBr = 0,175 x 0,347 = 0,060725 lunares
Explanation:
A glucose solution is 3.25% glucose by mass and has a density of 1.03 g/ml. what mass of glucose is contained in 58.2 ml of this solution?