Answer:
The mass of ascorbic acid in the sample is 0.1076g
Explanation:
In other words to determine ascorbic acid in a sample:
You are adding an amount of I₂. One part is reacting with ascorbic acid and the other with sodium thiosulphate. First, we need to calculate how much thiosulphate reacts to know the iodine that reacts with thiosulphate.
I₂ that reacts with S₂O₃²⁻:
Moles S₂O₃⁻: 0.02030L × (0.196mol / L) = 3.979x10⁻³ moles S₂O₃²⁻.
As 2 moles of S₂O₃²⁻ reacts per moles of I₂, moles of I₂ are:
3.979x10⁻³ moles S₂O₃²⁻ ₓ (1 mole I₂ / 2 moles S₂O₃²⁻) = 1.989x10⁻³ moles I₂
Now, initial amount of I₂ added to the sample is:
0.0500L ₓ (0.0520mol I₂ / L) = 2.600x10⁻³ moles I₂
That means moles of I₂ that react with ascorbic acid = Moles of ascorbic acid are:
2.600x10⁻³ moles I₂ - 1.989x10⁻³ moles I₂ =
6.11x10⁻⁴ moles I₂ = Moles C₆H₈O₆.
To convert moles of substance to mass we need to use molar mass of the substance (176.12g/mol for ascorbic acid):
6.11x10⁻⁴ moles C₆H₈O₆ ₓ (176.12g / mol) =
The mass of ascorbic acid in the sample is 0.1076gSome molecules such as iodine have two atoms to make up the substance, while others have thousands. A molecule of sugar has 45 atoms to make up the substance. If a sugar crystal has 1000 molecules, how many atoms are present?
Answer:
45000 atoms
Explanation:
From the question given above, we were told that a molecule of a sugar is made up of 45 atoms. This implies that:
1 molecule of sugar = 45 atoms
With the above idea in mind, we can obtain the number of atoms present in 1000 molecules of the Sugar as follow:
1 molecule of sugar = 45 atoms
Therefore,
1000 molecules of sugar = 1000 × 45 = 45000 atoms.
Therefore, there are 45000 atoms present in 1000 molecules of the sugar.
im just typing so u can give them brainliest :)
Explain why animals that come out at night have lots of rods in their retina
Answer:
Nocturnal animals, such as owls, tend to have wide pupils and several rod cells in their retina because wide pupil allow more light to enter the eyes and the rods cells in the retina are sensitive to dim light and are vital for night vision.
You take the following measurements in a density determination according to the procedure in part 1 using a triple beam balance and graduated cylinder. what is the density of liquid to be correct number of significant figure.
weight of cylinder + 19.7 mL liquid = 58.20 g
weight of cylinder + 10.2 mL liquid = 49.50 g
Answer:
0.916g/mL is the density of the liquid
Explanation:
Density is defined as the mass of a substance in a determined volume (Usually grams per mililiter).
The only difference between the first and second measurements is the volume of the liquid:
19.7mL - 10.2mL = 9.5mL is the difference in volume of the liquid between first and second weighs.
This volume, 9.5mL, weighs:
58.20g - 49.50g = 8.7g
As density is the ratio between mass in grams and volume in mL:
Density: 8.7g / 9.5mL
0.916g/mL is the density of the liquidHydrangea is a flower that presents in a variety colors including blue, white and pink. The color of some varieties of
hydrangea flowers can be controlled by the gardener growing the plant in a container and carefully regulating the pH. In
some instances aluminum sulfate, Al2(SO4)3, must be added as well. Perform an on-line search to identify what pH range
favors pink and blue color petals on hydrangea flowers. Also comment on the role of aluminum sulfate in determining the
color of the flower.
Answer:
Bigleaf hydrangeas are blue if the pH is between 5.0 and 5.5. The flowers
turn pink when the pH gets around 6.0. The flower color is dependent on
the concentration of aluminum ions (Al+++) in the soil. Aluminum is more
available to the plant when the soil is acidic, less available when the soil is
alkaline.The color of the cultivar called “Endless Summer” of H. macrophylla depends
on soil pH. Red or pink blooms result from neutral or basic soil (pH 7 and
above), whereas blue blooms indicate acidic conditions (pH less than 7).
Using her new telescope Ashley discovers a spherical meteor passing between the earth and the moon and measures it’s radius as 3 kilometers how many cubic kilometers are in the meteor
Answer:
113 km³
Explanation:
Step 1: Given data
Radius of the meteor (r): 3 km
Step 2: Calculate the volume (V) of the meteor
The meteor is spherical. Given the radius (r), we can calculate the volume of a sphere using the following expression.
V = 4/3 × π × r³
V = 4/3 × π × (3 km)³
V = 4/3 × π × 27 km³
V = 113 km³
The volume of the meteor is 113 km³.
The specific spatial arrangement of amino acid residues that are close to each other in the polypeptide chain is called______the structure of a protein.
a. primary.
b. secondary.
c. tertiary.
d. quaternary .
Answer:
c. tertiary.
Explanation:
In this case, we can review the definition of each level of structuration in the proteins:
Primary structure
In the primary structure, the amino acids are linked by peptide bonds. That is, the order of the amino acids is the criterion that defines this type of structure.
Secondary structure
In the secondary structure, we have to look at the way in which the protein is folded. The options are:
-) Beta-laminar: A structure in which the protein has a planar shape.
-) Alpha-helix: A structure in which the protein has a cross-strand form.
Tertiary structure
In the tertiary structure, the R groups that the amino acids have in the primary structure can generate interactions with each other. Interactions such as hydrogen bridges, dipole-dipole, hydrophobic interactions. This makes the protein have a very specific three-dimensional structure, on which its function depends.
Quaternary structure
In the quaternary structure, several subunits may be attached, or there may be prostatic groups (metals that can help to attach various protein units).
With all these in mind, the deffinition that fits with the description in the question is the tertiary structure.
I hope it helps!
The specific spatial arrangement of amino acid residues that are close to each other in the polypeptide chain is called the tertiary structure of a protein.
What is Protein?Protein structure is three dimensional in shape, where the atoms are arranged in amino acid chain. The chain is polypeptide containing many amino acid sequences.
The tertiary structure have a single polypeptide chain which is called the backbone.
Therefore, the specific spatial arrangement of amino acid residues that are close to each other in the polypeptide chain is called the tertiary structure of a protein.
Learn more on protein structure here,
https://brainly.com/question/17338734
While in Europe, if you drive 109 km per day, how much money would you spend on gas in one week if gas costs 1.10 euros per liter and your car's gas mileage is 22.0 mi/gal ? Assume that 1euro=1.26dollars.
Answer:
The amount is [tex]x = 113.3 \ dollars[/tex]
Explanation:
From the question we are told that
The distance traveled per day is [tex]l = 109\ km = \frac{109}{1.609} = 67.74 \ mi[/tex]
The cost of one liter is [tex]c = 1.10 \ euros/liter = 1.10 * 1.26 = 1.36 \ dollars/liter[/tex]
The car's gas mileage is [tex]b = 22.0 \ mi/gal[/tex]
Generally the amount of distance covered in one week is evaluated as
[tex]z = 67.74 * 7[/tex]
[tex]z = 474.18 \ mi[/tex]
The amount of gas used in one week by the car is mathematically represented as
[tex]k = \frac{ z}{ b}[/tex]
=> [tex]k = \frac{ 474.18}{ 22}[/tex]
=> [tex]k = 22 \ gal[/tex]
converting to liters
[tex]k = 22 * 3.78541=83.28 \ liters[/tex]
Thus the amount spent on gas in one week is
[tex]x = k * c[/tex]
=> [tex]x = 83.28 * 1.36[/tex]
=> [tex]x = 113.3 \ dollars[/tex]
Hydrophobic interactions help to stabilize the ________ structure(s) of a protein.
a. primary
b. secondary
c. secondary and tertiary
d. tertiary and quaternary
e. secondary and quaternary
Answer:
d. tertiary and quaternary
Explanation:
Form or shape of protein can be understood by its structure. The structure of protein encompasses four levels of protein :
Primary (Simplest layer of amino acids in polypeptide chain), Secondary (Atom - Backbone folding structure within polypeptide),Tertiary (R groups of amino acids), Quaternary (multiple polypeptide chain subunits).Hydrophobic Interactions refers to amino acids with non polar r group structure together on inside of protein, which leaves Hydrophobic amino acids outside to interact with surrounding water molecules.
These help to stabilise : D) Tertiary & Quaternary protein structures.
If the initial concentrations of A and B are 0M each, and the initial concentrations of C and D are 1.6M each, and Kc=4.7, what is the equilibrium concentration of A?
Answer:
[tex][A]_{eq}=0.095M[/tex]
Explanation:
Hello,
In this case, for the reaction:
[tex]A+B\rightleftharpoons C+D[/tex]
It is clear that the equilibrium expression is:
[tex]Kc=\frac{[C][D]}{[A][B]}[/tex]
Nevertheless, since the initial concentrations of both A and B are 0 M and C and D 1.6 M, we should invert the reaction:
[tex]C+D\rightleftharpoons A+B[/tex]
Thereby the equilibrium expression is also inverted:
[tex]Kc=\frac{[A][B]}{[C][D]}[/tex]
Which can be written in terms of the reaction extent and initial concentrations as shown below:
[tex]\frac{1}{Kc} =\frac{x*x}{([C]_0-x)([D]_0-x)}\\\\\frac{1}{0.47}= \frac{x*x}{(1.6-x)(1.6-x)}[/tex]
Hence, solving for [tex]x[/tex] we obtain:
[tex]x=0.095M[/tex]
In such a way, the equilibrium concentration of A is:
[tex][A]_{eq}=x=0.095M[/tex]
Best regards.
The equilibrium concentration of A will be "0.095 M". To understand the calculation, check below.
EquilibriumAccording to the question,
Initial concentration for A and B = 0 M
For C and D = 1.6 M
Kc = 4.7
Here the reaction:
→ A + B [tex]\rightleftharpoons[/tex] C + D
We know the expression,
Kc = [tex]\frac{[C][D]}{[A][B]}[/tex]
By inverting the reaction,
→ C + D [tex]\rightleftharpoons[/tex] A + B
Kc = [tex]\frac{[A][B]}{[C][D]}[/tex]
By substituting the values,
[tex]\frac{1}{Kc}[/tex] = [tex]\frac{x\times x}{([C]_0 -x)([D]_0 -x)}[/tex]
= [tex]\frac{x\times x}{(1.6 - x)(1.6 -x)}[/tex]
x = 0.095 M ([tex][A]_{eq}[/tex])
Thus the above approach is correct.
Find out more information about equilibrium here:
https://brainly.com/question/19340344
QUICK WILL MARK BRAINLIEST!!
Match each of the unknown ions to its appropriate description.
A− A) A nonmetal that gained one electron
B+ B) A metal that lost one electron
C2− C) A metal that lost two electrons
D2+ D) A nonmetal that gained two electrons
Answer:
Explanation:
1.A-
2.B+
3.D2+
4.C2-
Imagine that you are in the laboratory and find broken glass on your
workbench. Describe what you would do to handle this situation.
Your answer
Please help
Answer:
Laboratory is a place where all the experiments are to be done by the students or teachers so it should be safe and clean. I will not allow anyone inside until the glass peaces are cleaned
How many asymmetric centers are present in the open chain form of the aldohexose D-(-)-gulose?
A) 0
B) 1
C) 2
D) 4
E) 5
Answer:
D) 4
Explanation:
If we want to find the asymmetric centers, we must first remember that in an asymmetric center, in the carbon, we will have 4 different types of groups bonded to it.
Therefore we must look for carbons that have 4 different groups. With this in mind, we can look at each carbon.
Carbon 1
In this carbon, we have two bonds with the oxygen, therefore, we dont have 4 different groups. So, this is not an asymmetric center.
Carbon 2
In this carbon, we have an "OH" in the top, an hydrogen in the bottom a carbonyl group in the right, and a CHOH in the left. We have 4 different groups. So, this is an asymmetric center.
Carbon 3
In this carbon, we have an "OH" at the bottom, an hydrogen in the top, a CHOH group in the right (that is bonded to a carbonyl group), and a CHOH in the left. We have 4 different groups. So, this is an asymmetric center.
Carbon 4
In this carbon, we have an "OH" at the top, an hydrogen in the bottom a CHOH group in the right (that is bonded to a CHOH group), and a CHOH in the left. We have 4 different groups. So, this is an asymmetric center.
Carbon 5
In this carbon, we have an "OH" at the bottom, an hydrogen in the top, a CHOH group in the right (that is bonded to a CHOH), and a CH2OH in the left. We have 4 different groups. So, this is an asymmetric center.
Carbon 6
In this carbon, we have two bonds with hydrogens, therefore, we dont have 4 different groups. So, this is not an asymmetric center.
See figure 1
I hope it helps!
which of the following molexules would you predict to be most polar? i. co2 ii. cf4 iii. both have the same molecular polarity why?
Answer:
iii. both have the same molecular polarity
Explanation:
Both CF4 and CO2 are nonpolar molecules.
CF4 is a tetrahedral molecule, the compound is highly symmetrical hence the individual dipole moments due to the four C-F bonds cancel out thereby making the molecule to be nonpolar.
Similarly, the direction of the two dipoles in CO2 cancel out since they are directed in opposite directions making the molecule nonpolar.
The element carbon would be expected to form covalent bond(s) in order to obey the octet rule. Use the octet rule to predict the formula of the compound that would form between carbon and bromine, if the molecule contains only one carbon atom and only single bonds are formed. Formula:
Answer and Explanation:
The octet rue depicts the overall trend of chemical bonding in which atoms of an elements would seek to attain stability by filling out their valence shell with eight (8) electrons, giving it the same electronic configuration as a noble gas (specifically Argon).
Hence Carbon with 4 valence electrons (2, 4 electronic configuration) would take on four bromine atoms with 7 valence electrons (2, 8, 4 electronic configuration) each, giving each Br atom the single electron it needs to achieve octet stability.
Carbon tetrabromide
Chemical formula: [tex]CBr_{4}[/tex]
I hope this is a clear explanation
When 36.5g Of NaCL(s) is added to enough water to make 550.0 ml of solution, what is the molarity of the solution?
Answer:
1.1442 moles| litre,NaCl
Explanation:
RAM:56g|mole
number of moles=36.5g÷58g|mole =0.6293moles
0.6293 is contained in 550ml
=1000ml
[1000×0.6293]÷550 =1.1442moles| litre,NaCl
What do all living things need to survive?
Answer:
air,water,and food.
Explanation:
Some animals need to obtain their energy from plants.
HELP! pH = -log10[H+]. If pH 3.5 what is [H+]?
what subatomic particles are found in the nucleus of an atom
Answer:
Explanation:
The subatomic particles of protons and neutrons are found in the nucleus of an atom. Protons are particles with a positive charge, while neutrons have no charge. Electrons, which have a negative charge, are particles that can found orbiting outside the nucleus of an atom.
Answer: protons and neutrons
Explanation:
Calculate the MASS if the density is 2.34 g/mL and the volume is 12.50 mL.
Answer:
mass = 29.25 gExplanation:
The denisty of a substance can be found by using the formula
[tex]Density = \frac{mass}{volume} [/tex]
Making mass the subject we have
mass = Density × volumeFrom the question
Density = 2.34 g/mL
volume = 12.50 mL
Substitute the values into the above formula and solve for the mass
That's
mass = 2.34 × 12.50
We have the final answer as
mass = 29.25 gHope this helps you
Calculate the cell potential, the equilibrium constant, and the free energy change for
Ba(s)+Mn2+(aq,1M)→Ba2+(aq,1M)+Mn(s)
Given the following E degree values:
Ba2+(aq)+2e→Ba(s), E degree=−2.90V
Mn2+(aq)+2e→Mn(s),E degree=0.80V
Answer:
Explanation:
Ba(s) + Mn²⁺ (aq,1M) → Ba²⁺ (aq,1M) + Mn(s)
Ba⁺²(aq) +2e → Ba(s) , E° = −2.90 V
Mn⁺²(aq) +2e → Mn(s), E⁰ =0.80 V
Anode reaction :
Ba(s) → Ba⁺²(aq) +2e E° = −2.90 V
Cathode reaction :
Mn⁺²(aq) +2e → Mn(s) E⁰ =0.80 V
Cell potential = Ecathode - Eanode
Ecell = .80 - ( - 2.90 )
Ecell = 3.7 V .
equilibrium constant ( K ) :
Ecell = .059 log K / n
n = 2
3.7 = .059 log K / 2
log K = 125.42
K = 2.63 x 10¹²⁵ .
Free energy change :
ΔG = - n F Ecell
= - 2 x 96500 x 3.7
= 714100 J
= 7.141 x 10⁵ J .
Why are plastic containers preferred to glass containers for storing chemicals in the laboratory?
A mixture of glycine, alanine, aspartic acid, glutamic acid, leucine, lysine, histidine, asparagine, and phenylalanine are put into an electrophoresis apparatus, with the buffer pH=6.5. Sort each amino acid according to its charge in the buffer with a pH of 6.5.
a. Glycine
b. Alanine
c. Glutamic acid
d. Alanine aspartic acid
e. Leucine
f. Histidine asparagine
g. Phenylalanine
h. Lysine
Answer:
Positively charged: Lysine, Histidine
Negatively charged: Asparagine, Phenylalanine, Glutamatic acid, Alanine, Glycine, Leucine, Aspartic acid
Explanation:
The charge of an amino acid in solution is determined by its isoelectric point, pI, which is the characteristic pH in which the net electric charge of the amino acid is zero. In solutions of pH below the isoelectric point, the amino acid has a net positive charge whereas in solutions with pH above isoelectric point, the net charge on the amino acid is negative.
In a buffer solution of pH 6.5, the following charges are present in the amino acids given:
Positively charged: Lysine (pI = 9.74), Histidine (pI = 7.59)
Negatively charged: Asparagine (pI = 5.07), Phenylalanine (pI = 5.48), Glutamatic acid (pI = 3.22), Alanine (pI = 6.01), Glycine (pI = 5.97), Leucine (pI = 5.98), Aspartic acid (pI = 2.77)
What is the answer with the correct significant figures to the addition problem 1.2773 + 4.29
Answer:5.5673
Explanation: I searched it up for you
How many mg does a 643 kg sample contain?
Answer:
[tex]6.43x19^8mg[/tex]
Explanation:
Hello,
In this case, this unit conversion is performed by knowing that 1 kg of mass contains 1000 g and 1 g contains 1000 mg, therefore, the result is:
[tex]643kg*\frac{1000g}{1kg} *\frac{1000mg}{1g}\\ \\=6.43x10^8mg[/tex]
Regards.
What is the mass of sodium thiosulphate pentahydrate required to prepare 250cm3 of a 0.14mol/dm3 solution
Answer:
Strength of the sodium thiosulphate solution to be produced is 0.150M= 0.150mol/L×248.2g/mol=37.23g/L. So 1L or 1000 mL solution ...
Missing: 0.14mol/dm3 | Must include: 0.14mol/dm3
Answer:
Mass = 8.68g
Explanation:
Mass = Concentration × Molar mass × Volume (in dm^3)
but, concentration = 0.14 mol/dm^3.
volume = 250 cm^3 = 0.25 dm^3.
Molar mass of Na2S2O3 . 5H2O
= (2×23)+(2×32)+(3×16)+(5×18)
= 248 g/mol
hence, mass = 0.14 × 248 × 0.25
Mass = 8.68 g.
I HOPE IT'S OK?
liquid water has the density of 1000.0kg/m^3. Calculate the volume occupied by 0.250kg of liquid water.
Answer:
[tex]V=2.5x10^{-4}m^3\\\\V=0.25L[/tex]
Explanation:
Hello,
In this case, since the density is defined as the degree of compactness a substance has and is mathematically defined as:
[tex]\rho =\frac{m}{V}[/tex]
Thus, for this problem, as we know both the density and mass of water we can compute the volume as shown below:
[tex]V=\frac{m}{\rho}=\frac{0.250kg}{1000.0kg/m^3}\\ \\V=2.5x10^{-4}m^3\\\\V=0.25L[/tex]
Best regards.
A student completes a titration of an unknown diprotic acid. In this experiment, 0.79 g of the acid is dissolved in 250.0 mL of water. It requires 13.48 mL of 1.0 M NaOH to reach the second equivalence point. What is the molar mass of the acid?
Answer:
117.21g/mol
Explanation:
The reaction of a diprotic acid, H₂X with NaOH occurs as follows:
H₂X + 2NaOH → Na₂X + 2H₂O
Where 2 moles of NaOH reacts per mole of the diprotic acid
Knowing the moles of NaOH and the chemical equation we can determine the moles of the diprotic acid. With the moles and its mass we can find the molar mass of the acid, thus:
Moles of the diprotic acid:
To reach the equivalence point, it requires 13.48mL = 0.01348L of 1.0M NaOH. That is:
0.01348L × (1mol NaOH / L) = 0.01348 moles NaOH
As 2 moles of NaOH reacts per mole of the diprotic acid, moles of the acid are:
0.01348moles NaOH × (1mol H₂X / 2mol NaOH) = 0.00674 moles of H₂X
Molar mass:
The molar mass of a compound is the ratio between the mass you have per mole. As mass is 0.79g and moles are 0.00674moles, molar mass is:
Molar mass: 0.79g / 0.00674mol =
117.21g/molThe purpose of the best-fit line on an experimental scatterplot is to:_______.
a. The best-fit line allows us to predict behavior between measured data using its slope.
b. Ignore data points that don't fit the line.
c. Determine individual slopes between each set of data points
Answer: a. The best-fit line allows us to predict behavior between measured data using its slope.
Explanation:
A line of best fit is drawn through a scatter-plot to determine the direction of an relation between two quantities.
The line of best fit can be used to make prediction for the dependent variables.
Hence, the purpose of the best-fit line on an experimental scatter-plot is to predict behavior between measured data using its slope.
Hence, the correct option is "a."
Erica is bisecting an angle as shown. Which of the following should be her next step
Answer:
She should bisect from point M and then draw a line from the point where the arcs from M and N meet to point O
A reaction occurs via the following sequence of elementary steps. What is the reaction intermediate?
1st step: A + 2B → 2C
2nd step: 2C → D
Answer:
C is the reaction intermediate.
Explanation:
A reaction intermediate is a molecular structure that is formed during the reaction but then is converted in the final products.
Usually, these reaction intermediates are unestable and, for that reason, the lifetime of these structures is low.
In the reaction, you can see in the first step C is produced, but also, in the second step reacts producing D. As is produced and, immediately consumed,
C is the reaction intermediate.