The experimental design includes the controlled, independent, and dependent variables. The number of crickets and kinds of containers is two constant. Thus, options A and C are correct.
What are control variables?Control variables are the experimental element that remains fixed and unchanged in an experimental setup. They are constant and not are directly related to the interest of the investigation topic but are known to influence the results and observations.
The control variables can influence the dependent variable of the experiment as the number of crickets in each container and the type of container can indirectly alter the outcome and the conclusion of the experiment. The number of cricket will influence the effect of the temperature and the type of container can alter the survival rate.
Therefore, in options A and C. the number of cricket and container are two constants.
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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/molA 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.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.
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.
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g Which ONE of the following ionic compounds is insoluble in water? A) MgCO3 B) Li2CO3 C) NH4Br D) K3PO4 E) Pb(NO3)2
Answer:
A) MgCO₃ is insoluble
Explanation:
Based on the rules of solubility:
All nitrates are soluble. That means Pb(NO₃)₂ is soluble.
All ammonium ions are soluble. NH₄Br is soluble.
All phosphate are insoluble except when combined with group I ions (Li, Na, K...) K₃PO₄ is soluble.
Also, all carbonates are insoluble except when combined with group I ions. That means Li₂CO₃ is soluble and:
A) MgCO₃ is insoluble1. What does the atomic number of an element represent?
O A the number of neutrons
B the number of electrons
C the number of orbitals
D the number of protons
Answer:
D The number of protons
Substances that are composed of a network of atoms held together by covalent bonds are called
O A. ionic lattices
B. giant covalent structures
C. allotropes
D. diatomic networks
Answer:
giant covalent structures
Explanation:
Covalent solids are made up of atoms joined to one another by covalent bonds to form a giant lattice. The covalent bonds are very strong, this makes the giant covalent solids to be hard and possess high melting points. Covalent solids are nonconductors of electricity due to the absence of free electrons in the structure.
Diamond, graphite and boron nitride are all examples of giant covalent structures.
Some 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.
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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!
who discovered copper
Explanation:
The exact person is unkown cooper has been around for ages since 9000 BC in the Middle East are the earliest discoveries
Although various copper tools and decorative items dating back as early as 9000 BCE have been discovered, archaeological evidence suggests that it was the early Mesopotamians who, around 5000 to 6000 years ago, were the first to fully harness the ability to extract and work with copper
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.
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.
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Which acid could not be prepared by treating a Grignard reagent with CO2?
a. p-methylbenzoic acid.
b. cyclopentane carboxylic acid.
c. 4-oxopentanoic acid.
d. 3-methylbutanoic acid.
Answer:
4-oxopentanoic acid.
Explanation:
In this case, we must remember that the Grignard reaction is a reaction in which carbanions are produced. Carboanions have the ability to react with CO2 to generate a new C-C bond and a carboxylate ion. Finally, the acid medium will protonate the carboxylate to produce the carboxylic acid group.
The molecules that can follow the mechanism described above are the molecules: p-methylbenzoic acid, cyclopentane carboxylic acid and 3-methylbutanoic acid. (See figure 1)
In the case of 4-oxopentanoic acid, the possible carbanion will attack the carbonyl group to generate a cyclic structure and an alcohol group (1-methylcyclopropan-1-ol). Therefore, this molecule cannot be produced by this reaction. (See figure 2)
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-
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.
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.
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
Which of the following is true about the scientific method?
a
Each step is related to the others.
b
It is an iterative process.
c
All of the answers are correct.
d
It is a step-by-step process.
e
It involves a logical flow.
Answer:
It is a step by step process
Explanation:
You cannot do the experiment and lab report without following the steps
Hope this is correct and helpful
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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]
a chemist encounters an unknown metal. They drop the metal into a graduated cylinder containing water, and find the volume change is 3.2 mL. If the metal weighs 1.5g, what is the density in g/mL of the metal?
The density of metal will be "0.469 g/mL".
The given values in the question are:
Mass of metal = 1.5 gVolume of metal or Volume change = 3.2 mLNow,
The density of metal will be:
→ [tex]Density = \frac{Mass}{Volume}[/tex]
By substituting the given values, we get
→ [tex]= \frac{1.5}{3.2}[/tex]
→ [tex]=0.469 \ g/mL[/tex]
Thus the above is the appropriate answer.
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The density of the metal is 0.47 g/mL
The density of an object is defined as the mass of the object per unit volume of the object.
Density = mass / volumeWith the above formula, we can obtain the density of the metal. This is illustrated below:
Volume of metal = change in volume of water = 3.2 mL
Mass of metal = 1.5 g
Density of metal =?Density = mass / volume
Density = 1.5 / 3.2
Density of metal = 0.47 g/mLTherefore, the density of the metal is 0.47 g/mL
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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
During a titration, the solution with the unknown concentration is called the _____.
Answer:
Analyte.
Explanation:
Hello,
In this case, in a titration, an analyte is known as the the substance whose quantity or concentration is to be carefully determined (initially unknown) by using a titrant with a controlled volume and an accurately-known concentration which is also called a standard solution.
You can verify this by considering the attached picture.
Regards.
Hydrangea 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).
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
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
The 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."
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)
Why are plastic containers preferred to glass containers for storing chemicals in the laboratory?
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.
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.