Answer:
Have you ever touched a fish? Most fish will feel a bit rough - due to their scales. Some, like sharks, will feel like sandpaper. Even fish with small, smoother scales will feel a bit like that. Amphibians don’t have scales, and most species will be wet to some degree - they have to keep their skin moist or they’ll die. A few groups, like toads and newts, have rougher skin, which is heavier and thicker, which allows them to retain moisture better away from water.
Functionally, the big thing about amphibian skin is that it is semi-permeable. Amphibians can breathe through their skin - all amphibians can get some oxygen through their skin, but some species of salamanders get all their oxygen that way - they have no lungs or gills. The skin can also allow water in - sort of like a paper towel. The bad thing is that other chemicals can pass through the skin, too - pollutants and other chemicals tend to affect amphibians far more than they do other groups.
Amphibians also shed their skin - fish do not. People don’t tend to see frogs shedding their skin often, though, since they eat it to regain nutrients and other resources in the skin.
Finally, since amphibian skin offers no defense against predators in the way that scales do, and limited barrier against disease the way non-amphibian skin does (shedding helps), the skin of many amphibians contain toxins, and some of them have anti-fungal properties (typically due to symbiotic bacteria). Many species have evolved chemical defenses in the skin, while others have glands that produce toxins that can be secreted outside of the skin.
The skin can withstand dessication more than the fish.
They have moist skin used as respiratory surface during deep sleep / hibernation.
They have moist skin due to secretion of mucus by glands under the skin.
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A laboratory utilizes a mixture of 10% dimethyl sulfoxide (DMSO) in the freezing and long-term storage of embryonic stem cells. If DMSO has a specific gravity of 1.1004, calculate the specific gravity, to four decimal places, of the mixture (assume water to be the 90% portion).
Answer:
The correct answer is "1.0100".
Explanation:
Let the volume of mixture be 100 ml.
then,
The volume of DMSO will be 10 mL as well as that of water will be 90 mL.
DMSO will be:
= [tex]10\times 1.1004[/tex]
= [tex]11.004 \ g[/tex]
The total mass of mixture will be:
= [tex]90+11.004[/tex]
= [tex]101.004 \ g[/tex]
Density of mixture will be:
= [tex]\frac{Mass}{Volume}[/tex]
= [tex]\frac{101.004}{100}[/tex]
= [tex]1.01004 \ g/mL[/tex]
hence,
Specific gravity of mixture will be:
= [tex]\frac{Density \ of \ mixture}{Density \ of \ water}[/tex]
= [tex]\frac{1.01004}{1}[/tex]
= [tex]1.0100[/tex]
The reaction responsible for producing the heat that maintains the temperature of your body is
Answers
A.
metabolism.
B.
catabolism.
C.
anabolism.
D.
photosynthesis.
Question
Answer:
A
Explanation:
it increase the rate of reaction when necessary
The chemical change that is responsible for producing the heat that maintains the temperature of your body is metabolism.
What is chemical change?
Chemical changes are defined as changes which occur when a substance combines with another substance to form a new substance.Alternatively, when a substance breaks down or decomposes to give new substances it is also considered to be a chemical change.
There are several characteristics of chemical changes like change in color, change in state , change in odor and change in composition . During chemical change there is also formation of precipitate an insoluble mass of substance or even evolution of gases.
There are three types of chemical changes:
1) inorganic changes
2)organic changes
3) biochemical changes
During chemical changes atoms are rearranged and changes are accompanied by an energy change as new substances are formed.
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A chemist determines by measurements that moles of bromine liquid participate in a chemical reaction. Calculate the mass of bromine liquid that participates. Round your answer to significant digits.
Answer:
5.20 grams of Br₂
Explanation:
From our previous knowledge;
We understand that:
The number of moles of a given element = mass of the element divided by its molar mass.
Mathematically:
[tex]\mathbf{no \ of \ moles =\dfrac{ mass}{ molar \ mass}}[/tex]
From the given information, let's assume that the 0.065 moles of liquid -bromine partake in the reaction.
From the periodic table, the molar mass of Bromine is = 79.9 g/mol
As such, the mass of liquid that partakes is calculated as:
0.065 mol = mass/ 79.9 g/mol
mass = 0.065 mol × 79.9 g/mol
mass of liquid that partakes in the reaction = 5.20 grams of Br₂
Balance the redox reaction Al(s) + MnO4^- (aq) --> MnO2 (s) + Al(OH)4^- (aq) in aqueous basic solution
Answer:
Al + MnO4- + 2H2O → Al(OH)4- + MnO2
Explanation:
First of all, we out down the skeleton equation;
Al + MnO4- → MnO2 + Al(OH)4-
Secondly, we write the oxidation and reduction equation in basic medium;
Oxidation half equation:Al + 4H2O + 4OH- → Al(OH)4- + 4H2O + 3e-
Reduction half equation:MnO4- + 4H2O + 3e- → MnO2 + 2H2O + 4OH-
Thirdly, we add the two half reactions together to obtain:
Al + MnO4- + 8H2O + 4OH- + 3e- → Al(OH)4- + MnO2 + 6H2O + 3e- + 4OH-
Lastly, cancel out species that occur on both sides of the reaction equation;
Al + MnO4- + 8H2O→ Al(OH)4- + MnO2 + 6H2O
The simplified equation now becomes;
Al + MnO4- + 2H2O → Al(OH)4- + MnO2
what vent system nitrogen vessel used to?
it's helpful
you can try this answer
Select all that are True.
a. For an isoelectronic series, the species with the most negative charge has the smallest first ionization energy.
b. The removal of an electron from a neutral atom results in a release of energy in the form of heat.
c. For an isoelectronic series, the species with the most positive charge has the smallest first ionization energy.
Based on the reaction below:
[tex]N_2 + 3H_2[/tex] ↔ [tex]2NH_3 + heat[/tex]
If we decrease the temperature, equilibrium will shift towards the...
Please explain!
N₂ + 3H₂ ⇄ 2NH₃ + heat
In the given equilibrium, we notice that the heat is on the right. which means that if the heat requirements don't meet, the reactants on the right will no longer react due to the lack of heat
but because the reactants on the left don't have such weaknesses, they will keep reacting hence producing more and more ammonia until a new equilibrium is reached
where there will be more ammonia and less nitrogen and hydrogen as compared to the equilibrium we had initially
Answer:
Explanation:
heat is given out as 1 of the products, along w/ NH3 in the forward reaction. so its an exothermic reaction
decreasing temperature favors exothermic reaction as more heat can be absorbed by the environment
so equilibrium will shift towards the products
Determine the value of the equilibrium constant for the following reaction, where the following amounts of each species are present at equilibrium in a 5.00 L container: 1.34 mol HCl, 4.30 mol O2, 30 g H2O, and 2.42 mol Cl2.
4 HCl(g) O2(g) ----> 2 H2O(l) 2 Cl2(g)
Explanation:
here's the answer to your question about
Aqueous hydrobromic acid HBr will react with solid sodium hydroxide NaOH to produce aqueous sodium bromide NaBr and liquid water H2O . Suppose 4.9 g of hydrobromic acid is mixed with 3.86 g of sodium hydroxide. Calculate the maximum mass of sodium bromide that could be produced by the chemical reaction. Round your answer to 2 significant digits.
Answer:
6.2g of NaBr are produced
Explanation:
The reaction of HBr with NaOH occurs as follows:
HBr + NaOH → NaBr + H2O
Where 1 mole of each reactant produce 1 mole of NaBr
To solve this question we need to find the moles of each reactant using their molar mass. With moles we can find limiting reactant and the moles (And mass) of NaBr produced, as follows:
Moles HBr -Molar mass: 80.9119g/mol)-
4.9g * (1mol/80.9119g) = 0.0606 moles HBr
Moles NaOH -Molar mass: 40g/mol-
3.86g * (1mol/40g) = 0.0965 moles NaOH
As the reaction is 1:1 and the moles of HBr < Moles NaOH, the limiting reactant is HBr and moles of NaBr produced are 0.0606 moles.
The mass of NaBr (Molar mass: 102.894g/mol) is:
0.0606 moles * (102.894g/mol) =
6.2g of NaBr are producedWhich process refers to the dissociation of Naci into Na+ and Ci+?
Answer:
dissolution is the process
What is the molarity of a solution that contains 17g of NH₃ in 0.50L of solution?
Please explain as well!
Explanation:
Because molarity is mol/L, we'll have to convert 17g to mol.
After obtaining the mol, we'll divide that by the volume to obtain Molarity.
[tex]\\ \sf\longmapsto NH_3[/tex]
[tex]\\ \sf\longmapsto 14u+3(1u)[/tex]
[tex]\\ \sf\longmapsto 14u+3u[/tex]
[tex]\\ \sf\longmapsto 17u[/tex]
[tex]\\ \sf\longmapsto 17g/mol[/tex]
Moles of Ammonia:-
[tex]\boxed{\sf No\:of\:moles =\dfrac{Given\:mass}{Molar\:mass}}[/tex]
[tex]\\ \sf\longmapsto No\:of\:moles=\dfrac{17}{17}[/tex]
[tex]\\ \sf\longmapsto No\;of\:moles=1mol[/tex]
Volume of solution=0.50LWe know
[tex]\boxed{\sf Molarity=\dfrac{Moles\:of\:solute}{Volume\:of\: Solution\:in\:L}}[/tex]
[tex]\\ \sf\longmapsto Molarity=\dfrac{1}{0.50}[/tex]
[tex]\\ \sf\longmapsto Molarity=2M[/tex]
A chunk of a metal alloy displaces 0.58 L of water and has a mass of 2.9 kg. What is the density of the alloy in g/cm3?
Answer:
5g/cm3
Explanation:
firstly convert the litres and kilograms to grams and centimeters.
1l is equivalent to 1000cm3
0.58×1000
580cm3
and 1kg is equivalent to 1000g
2.9×1000
2900
then find the density by using the formula
density=mass/volume
=2900g/580cm3
=5g/cm3
I hope this helps
When should a line graph be used
Answer:
Line graphs are used to track changes over short and long periods of time. When smaller changes exist, line graphs are better to use than bar graphs. Line graphs can also be used to compare changes over the same period of time for more than one group.
If the Ksp of NaCl is experimentally determined to be 43.9, then what is the concentration of Na (in M) when it begins to crystallize out of solution
Answer:
6.63 M
Explanation:
NaCl(s) ---> Na^+(aq) + Cl^-(aq)
Given that [Na^+] = [Cl^-] = s
Where s= concentration of the both ions
Ksp = s^2
s= √Ksp
s= √43.9
s= 6.63 M
The concentration of Na (in M) obtained when it begins to crystallize out of solution is 6.63 M
What is solubility of product?The solubility of product (Ksp) is defined as the concentration of products raised to their coefficient coefficients. This is illustrated below:
mX <=> nY + eZ
Ksp = [Y]^n × [Z]^e
Dissociation equationNaCl(aq) → Na⁺(aq) + Cl¯(aq)
Let the concentration of Na⁺ be yLet the concentration of Cl¯ be yHow to determine the concentration of Na⁺ Solubility of product (Ksp) = 43.9Concentration of Cl¯ = yConcentration of Na⁺ = y =?Ksp = [Na⁺] × [Cl¯]
43.9 = y × y
43.9 = y²
Take the square root of both side
y = √43.9
y = 6.63 M
Thus, the concentration of Na⁺ is 6.63 M
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CH3CH2OH
______ions
in an aqueous solution.
А
forms
B
does not form
Answer:
When ionic compounds dissolve, they break apart into ions which are then able to conduct a current ( conductivity ). ... Many molecular compounds, such as sugar or ethanol, are nonelectrolytes. When these compounds dissolve in water, they do not produce ions.
Explanation:
Ethanol is an organic compound with an alcoholic functional group and is nonelectrolytes. Ethanol (CH₃CH₂OH) does not form ions in an aqueous solution. Thus, option B is correct.
What are nonelectrolytes?Nonelectrolytes are substances that do not dissociate readily to yield ions and also are poor conductors of electricity and heat due to a lack of charged ions.
Ethanol is a nonelectrolyte that does not show conductivity and can be dissolved in water without producing ions. They cannot forms ions upon dissociation as covalent bonds are present.
Instead of ions that have covalent compounds that lack the ability to transfer the electron to conduct the electrical charge. Glucose, ethanol, etc. are some examples of a nonelectrolyte.
Therefore, option B. ethanol does not form ions is the correct blank.
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Give me an atom with the following characteristics:
Lanthanide series
Boron
Chalogen
Alkaline Earth metal
Explanation:
Lanthanide series= E4
Boron=Si
Chalogen=O
Alkaline Earth metal =M9
what is food nutrients
Answer:
Nutrients arw compounds in foods essential to life and heath
Answer: In simple terms nutrients are the energy that you get from food certain foods give more nutrients and others give close to none. That is what nutrients in your food is
Explanation:
8) Determine whether mixing each pair of the following results in a buffera. 100.0 mL of 0.10 M NH3 with 100.0 mL of 0.15 MNH4Cl b. 50.0 mL of 0.10 M HCL with 35.0 mL of 0.150 M NaOHc. 50.0 mL of 0.15 M HF with 20.0 mL of 0.15 M NaOHd. 175.0 mL of 0.10 M NH3 with 150.0 mL of 0.12 M NaOH
Answer:
a. 100.0 mL of 0.10 M NH₃ with 100.0 mL of 0.15 M NH₄Cl.
c. 50.0 mL of 0.15 M HF with 20.0 mL of 0.15 M NaOH.
Explanation:
A buffer system is formed in 1 of 2 ways:
A weak acid and its conjugate base.A weak base and its conjugate acid.Determine whether mixing each pair of the following results in a buffer.
a. 100.0 mL of 0.10 M NH₃ with 100.0 mL of 0.15 M NH₄Cl.
YES. NH₃ is a weak base and NH₄⁺ (from NH₄Cl ) is its conjugate base.
b. 50.0 mL of 0.10 M HCl with 35.0 mL of 0.150 M NaOH.
NO. HCl is a strong acid and NaOH is a strong base.
c. 50.0 mL of 0.15 M HF with 20.0 mL of 0.15 M NaOH.
YES. HF is a weak acid and it reacts with NaOH to form NaF, which contains F⁻ (its conjugate base).
d. 175.0 mL of 0.10 M NH₃ with 150.0 mL of 0.12 M NaOH.
NO. Both are bases.
Predict the reactants of this chemical reaction. That is, fill in the left side of the chemical equation. Be sure the equation you submit is balanced. (You can edit both sides of the equation to balance it, if you need to.)
Note: you are writing the molecular, and not the net ionic equation.
NaClO3(aq) + H2O(l)
Answer:
HClO₃(aq) + NaOH(aq) ⇒ NaClO₃(aq) + H₂O(l)
Explanation:
We have the products of a reaction and we have to predict the reactants. Since the products are salt and water, this must be a neutralization reaction. In a neutralization reaction, an acid reacts with a base. To form NaClO₃, the acid must be HClO₃(aq) and the base NaOH(aq). The balanced chemical equation is:
HClO₃(aq) + NaOH(aq) ⇒ NaClO₃(aq) + H₂O(l)
Two chemicals A and B are combined to form a chemical C. The rate, or velocity, of the reaction is proportional to the product of the instantaneous amounts of A and B not converted to chemical C. Initially, there are 100 grams of A and 50 grams of B, and for each gram of B, 2 grams of A is used. It is observed that 25 grams of C is formed in 9 minutes. How much is formed in 36 minutes
Answer:
In 36 minutes, 100 grams of Chemical C is formed.
Explanation:
Combination of chemicals A and B = chemical C
Chemical A available = 100 grams
Chemical B available = 50 grams
Proportion of A mixed with C = A2
Proportion of B mixed with C = B1
Therefore, Chemical C = A2 + B1
If 25 grams of C is formed in 9 minutes
In one minute 25/9 grams of C will be formed
Therefore, in 36 minutes, 25/9 * 36 = 100 grams
A bond dissociation energy is A) The energy required to remove an electron from an atom. B) The energy released when an ionic compound dissociates in water. C) The energy required to break a covalent bond. D) The energy produced in a chemical reaction that breaks chemical bonds.
Answer:
The energy required to break a covalent bond
Explanation:
When a chemical bond is formed, energy is released. When a chemical bond is broken, energy is absorbed.
We define the bond dissociation energy as the energy required to break a covalent bond. The process of covalent bond cleavage is endothermic hence energy is absorbed for the process to occur.
Which of the following compounds would you expect to be an electrolyte?
N2
CH4
H2O
O2
КСІ
Answer:
N2 but i really didn't know
The compound that would be expected to be an electrolyte is : ( A ) N₂
What is an electrolyte
An electrolyte is any subsatnce which conducts electircity when dissolved in a solvent such as water. From the question the compound that can conduct electricty when dissolved in water is N₂
Hence we can conclude that The compound that would be expected to be an electrolyte is : ( A ) N₂
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Given the following formula for calculating the ionization energy of one-electron species such as Li2+, He+, and H, calculate the ionization energy (in J/mol) for B4+. Use scientific notation in answers (ex: 1E10, 3.20E-6)
Answer:
The answer is "[tex]32819.9 \ \frac{J}{mol}\\\\[/tex]"
Explanation:
[tex]Boron: 5^{B}\to 1s^2 2s^2 2p^1[/tex]
[tex]\Delta E=-2.18\times 10^{-18}\ \frac{J}{atom}\ (\frac{1}{\infity^2}-\frac{1}{n^2_{initial}})(z^2) (6.022\times 10^{23}\ \frac{atom}{mol})\\\\[/tex]
[tex]=-2.18\times 10^{-18}\ \frac{J}{atom}\ (0-\frac{1}{1})(5^2) (6.022\times 10^{23}\ \frac{atom}{mol})\\\\ =2.18\times 10^{-18}\times 25 \times 6.022\times 10^{23}\ (\frac{J}{mol})\\\\ =328.199 \times 10^{5}\ (\frac{J}{mol})\\\\ =32819 \times 10^{3}\ (\frac{J}{mol})\\\\ =32819.9 \ (\frac{J}{mol})\\\\[/tex]
1. Metallic strontium crystallizes in a face-centered cubic lattice, with one Sr atom per lattice point. If the edge length of the unit cell is found to be 608 pm, what is the metallic radius of Sr in pm?
2. The substance beta manganese is found to crystallize in a cubic lattice, with an edge length of 630.0 pm. If the density of solid beta manganese is 7.297 g/cm3, how many Mn atoms are there per unit cell?
Answer:
[tex]r=215pm[/tex]
[tex]N_{Mn}=20[/tex]
Explanation:
From the question we are told that:
Edge length of the unit cell [tex]l=608pm[/tex]
a)
Generally the equation for The relationship between edge length and radius is mathematically given by
[tex]4r=\sqrt{2a}[/tex]
Therefore
[tex]4r=\sqrt{2*608}[/tex]
[tex]r=\frac{\sqrt{2*608}}{4}[/tex]
[tex]r=215pm[/tex]
b)
From the question we are told that:
Density [tex]\rho=7.297[/tex]
Edge length of [tex]l=630.0 pm=>630*10^-{10}[/tex]
Therefore Volume is given as
[tex]V=l^3[/tex]
[tex]V=630*10^-{10}^3[/tex]
[tex]V=2.50047*10^{−22}[/tex]
Generally the equation for Mass is mathematically given by
[tex]m=Volume*density[/tex]
[tex]m=V*\rho[/tex]
[tex]m=2.50047*10^{−22}*7.297[/tex]
[tex]m=1.83*10^{-21}g[/tex]
Therefore Molarity is given as
[tex]n=\frac{M}{Molar M}[/tex]
[tex]n=\frac{1.83*10^{-21}g}{55}[/tex]
[tex]n=3.32*10^{-23}[/tex]
Finally The atoms in a unit cell is
[tex]N_{Mn}=Moles*Avogadro\ constant[/tex]
[tex]N_{Mn}=3.32*10^{-23}*6.023*10^{23}[/tex]
[tex]N_{Mn}=20[/tex]
Considering a fish breeder decided to breed small fishes which needs a pH between 6,0 to 7,0 to stay alive. He needs to adjust the water's pH that is 5,0 to a value of 6.5, having available only calcium carbonate. The mass in mg added to 5L of water is about:
A)2,5
B)5,5
C)6,5
D)7,5
E)9,5
Consider an equilibrium (K1) that is established after 10 mL of compound A and 10 mL of compound B are mixed. Now, imagine the equilibrium (K2) where 1 mL of compound A is added to 100 mL of compound B. How are K1 and K2 related algebraically (read this question VERY carefully, at least one more time)
The equilibrium constant K₁ = Equilbrium constant K₂.
The equilibrium constant, K, of a reaction, is defined as:
"The ratio between concentration of products powered to their reaction quotient and concentration of reactants powered to thier reaction quotient".
For the reaction:
aA + bB ⇄ cC + dD
The equilibrium constant, K, is:
[tex]K = \frac{[C]^c[D]^d}{[A]^a[B]^b}[/tex]
Now, assuming the reaction of the problem is 1:1:
A + B ⇄ C + D
[tex]K = \frac{[C][D]}{[A][B]}[/tex]
The concentrations of the reactants are directly proportional to the volume added. Thus, we can assume that concentration = Volume. Replacing for K₁ and K₂:
[tex]K_1 = \frac{[C][D]}{[10mL][10mL]} = K_1 = \frac{[C][D]}{100mL^2}[/tex]
In the same way:
[tex]K_2 = \frac{[C][D]}{[1mL][100mL]} = K_2 = \frac{[C][D]}{100mL^2}[/tex]
Thus, we can say:
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When would exposure to a potentially harmful substance most likely to damage many organs in a developing embryo?
The chemical formula for strontium sulfide is SrS . A chemist measured the amount of strontium sulfide produced during an experiment. She finds that 199.g of strontium sulfide is produced. Calculate the number of moles of strontium sulfide produced. Be sure your answer has the correct number of significant digits.
Answer:
The number of moles of strontium sulfide produced is:
= 1.663.
Explanation:
Chemical formula for strontium sulfide = SrS
Production of strontium sulfide = 199g
1 mole = 1 moles Strontium Sulfide, which is equal to 119.685 grams
The number of moles of strontium sulfide produced = 1.663 (199/119.685)
The number of moles of strontium sulfide produced is the dividend of the amount of strontium sulfide produced during the experiment divided by the mass of 1 mole.
Select all of the statements that are true about a buffer solution. A buffer solution always changes color when the pH changes. A buffer solution reacts with basic solutions. A buffer solution has a pH of 7. A buffer solution resists small changes in pH. A buffer solution reacts with acidic solutions. At what point on the titration curve for a weak acid is the solution a buffer
Answer: A buffer solution reacts with basic solutions.
A buffer solution resists small changes in pH.
A buffer solution reacts with acidic solutions.
Explanation:
A buffer solution simply refers to an aqueous solution that consist of a mixture of a weak acid and the conjugate. From the options given, the ones application to a buffer solution include:
• A buffer solution reacts with basic solutions.
• A buffer solution resists small changes in pH.
• A buffer solution reacts with acidic solutions.
(d) 40g of sulphur
Calculate the number of moles of 40g of sulphur
Answer:
It is 1.25 moles
Explanation:
Molar mass of sulphur = 32 g
[tex]{ \bf{moles = \frac{given \: mass}{molar \: mass} }} [/tex]
Substitute:
[tex]{ \sf{moles = \frac{40}{32} }} \\ { \sf{ = 1.25 \: moles}}[/tex]
