Explanation:
Answer
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The initial temperature of the coffee T0=100∘C.
The temperature of the room 15∘C.
Let T be the temperature at time t in minutes.
By Newton's law of cooling,
dtdTα(T−15)
∴dtdT=k(T−15)
⇒T−15dT=kdt
⇒∫T−15dT=∫kdt
⇒log(T−15)=kt+logc
⇒log(cT−15)=kt
⇒T−15=cekt
At t=0,T=100
We have 100−15=ce0⇒85=c
Thus we get T−15=85ekt.
When t=5minutes,T=60
⇒60−15=85e5k.
⇒e
P.1 is a variant of SARS-CoV2. This is the so-called "Brazil variant". It has the amino acid the substitution N501Y in the spike protein on the virus surface. In cellular fluids at ~pH 7 the wild type spike protein has a net negative charge. This substitution will make the spike protein
more negative
less hydrophobic
able to absorb move UV light
less negative
There are various variants of Cov id virus. The Brazilian variant P also known as Gamma variant is the third variant of the original SARS-CoV2.
The correct answer is more negative
This variant has raised concerns since it has ability to spread more quickly then previous variants and this is more negative variant.
It is assumed that Cov id variant Gamma and Delta has ability to absorb move UV light but this is not proved yet and research is underway.
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Class 8 fossil fuels are
Answer:
fossil fuels are non-renewable resources .
The peptide alanylglutamylalanylglycylalanylleucine has:
No free carboxyl groups
Five peptide bonds
A disulphide bridge
Two free amino groups
Peptide bonds are formed between carboxyl groups of one amino acid and amino group of another dehydration synthesis.
The correct answer is Five Peptide bonds
The peptide of "alanylglutamylalanylglycylalanylleucine" will have four or more peptide bonds.
It will also have free carboxyl groups.
The chain of amino acids is polypeptide.
Usually C terminal amino acid is the residual at the end of peptide bonds formation.
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Describe the factors influencing chemical bonds and the
characteristics of an ionic and a covalent bond.
Explanation:
factors affecting chemical bonds
a. electronegativity difference
b. size
c. charges
characteristics of Ionic bond
a. high melting point
b. they are soluble in polar solvents
c. they don't conduct electricity in solid state
characteristics of covalent bonds
a. they are insoluble in polar solvents
b. they don't conduct electricity
c. low melting point
why does D2O
have a higher boiling point than H2O
Answer:
deuterium is heavier isotope of hydrogen need
high weight of atom will lead to higher boiling point
Help please due today
Edit : OPTION C is the answer
Option B is the best, Even though the cost is 30 Billion it essentially takes Lesser time to construct. For Plan A, They would have to construct the overground railway and then take a lot of time and effort to create wildlife corridors and then plant trees. Plan B takes much less time compared to plan A and might as well have a lesser impact on the environment!
how do elasticity ang flexibility differ?
Answer:
the object will regain its original form as soon as the deforming force is removed. ... Flexibility means the object is just easily deformed, and will stay that way.
Explanation:
What is the oxidation state for bh3
Answer:
As hydrogen is more electronegative than boron, in BH3 the oxidation number of hydrogen should be taken as -1. (E. N. of B = 2.0 & E. N. of H = 2.1)
Suppose, oxidation number of B is x.
So, we can write, x + 3*(-1) = 0
=> x = +3
Therefore, oxidation num
Explanation:
As hydrogen is more electronegative than boron, in BH3 the oxidation number of hydrogen should be taken as -1. (E. N. of B = 2.0 & E. N. of H = 2.1)
Suppose, oxidation number of B is x.
So, we can write, x + 3*(-1) = 0
=> x = +3
Therefore, oxidation num
which of the following is an acid?
HF
KOH
LIF
NH3
Based on a pH scale, the chemical compound which is classified as an acid is: A. Hydrogen fluoride (HF).
What is a pH scale?A pH scale can be defined as a tool that is designed and developed for the measurement of the molar concentration of hydrogen ions (H⁺) in both acidic and alkaline (basic) solutions.
This ultimately implies that, a pH scale can be used to measure and specify the acidity, neutrality or basicity of any chemical solution.
In this scenario, the pH of each of the given chemical compound are as follows:
Hydrogen fluoride (HF): it has a pH of 1.0 but it's a weak acid.Potassium hydroxide (KOH): it has a pH of 13 and as such it's a strong base.Lithium fluoride (LIF): it has a pH of 7.5 and as such it's neutral.Ammonia (NH₃): it has a pH of 10 and as such it's a weak base.Read more on pH here: brainly.com/question/24233266
The freezing point of a substance is -20°C. Its boiling point is 120°C.
a. At 80°C the substance is in the state
b. At -50°C the substance is in the state.
C. At 140°C the substance is in the state.
Answer:
a. liquid
b. solid
c. gas, (should be at it's boiling point)
Explanation: If the normal melting point of a substance is below room temperature, the substance is a liquid at room temperature. Benzene melts at 6°C and boils at 80°C; it is a liquid at room temperature. If both the normal melting point and the normal boiling point are above room temperature, the substance is a solid.
if you need an explanation to each lmk
Calculate the percentage of O in CH₃COOH
Answer:
53.28%
(you could also write 55.33%, but I rounded it so just go with the answer above ---> 53.28%)
Explanation:
How is magma formed?
Answer:
“Magma” is exclusively found and formed beneath the earth’s surface. Once magma is on or above the surface of the earth it is referred to as “lava.” Magma is typically formed by extreme temperature melting solid rock within the earth. Pressure and rock composition can also affect magma formation. High pressure can help magma be “squeezed” from partially molten rock. Likewise, as rocks are usually composed of different minerals with different melting points, magma formation from rocks is usually only partial and uneven.
Explanation:
Name the given element.
of lesson matter .
Answer:
For a given element, the number of postively charged, massive nuclear particles, the number of protons, is fixed. ... Because the number of protons determines Z , the atomic number, which determines the identity of the atom. The nucleus can also contains neutrons, massive, neutrally charged nuclear particles.
Explanation:
A sample of gas is held at constant pressure. If the number of moles of this sample of gas is halved and the absolute temperature of this sample of gas is doubled what happens to the volume of the gas?
Select one
a. The volume is doubled
b. The volume is halved
c The volume is quadrupled
d. The volume is quartered
o
e The volume stays the same.
Answer:
since temperature is proportional related to temperature, if temp. is doubled, then volume will double as well
A sample of gas is held at constant pressure. If the number of moles of this sample of gas is halved and the absolute temperature of this sample of gas is doubled, then the volume of gas is doubled. Therefore, option A is correct.
What is pressure ?The SI unit for pressure is the pascal (Pa), which is equal to one newton per square meter (N/m2) of force per unit area of surface. An object's pressure is inversely proportional to the area it is pressing on and inversely proportional to the force it applies.
To keep the pressure and volume product constant, if the pressure is cut in half, the volume must be doubled. Therefore, the volume will double if the pressure on a gas is reduced by half.
As the gas volume decreases, the molecules hit the walls more frequently, increasing the pressure; conversely, as the volume grows, the molecules must travel a greater distance before hitting the walls.
Thus, option A is correct.
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A fusion reaction releases energy because the binding energy of the resulting nucleus:______.
a. is released in the process.
b. is equal to the binding energy of the original nuclei.
c. is absorbed in the process.
d. is less than the binding energy of the original nuclei.
e. is greater than the binding energy of the original nuclei.
Answer:
a. is released in the process
Explanation:
In fusion reaction the nucleus is unstable so it releases its binding energy resulting in decreasing its mass so it becomes more stable.
a cup of coffee changes from a temperature of75ﾟC to 12ﾟC. What is the change in temperature in ﾟC
Explanation:
why is because I never did this class
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Determine what product will be produced at the negative electrode for the following reaction:
2KCl(aq) + 2H20(1) -> H2(g) + Cl2(g) + 2KOH(aq)
A. H2
B. Cl2
с. КОН
D. K
Answer:
Choice A. [tex]\rm H_{2}[/tex] would be produced at the negative electrode.
Explanation:
Ionic equation for this reaction:
[tex]2\, {\rm K^{+}} + 2\, {\rm Cl^{-}} + {2\, \rm H_{2} O} \to {\rm H_{2}} + {\rm Cl_{2}} + 2\, {\rm K^{+}} + {\rm 2\, OH^{-}}[/tex].
Net ionic equation:
[tex]2\, {\rm Cl^{-}} + 2\, \rm H_{2} O} \to {\rm H_{2}} + {\rm Cl_{2}} + 2\, {\rm OH^{-}}[/tex].
Half-equations:
[tex]2\, {\rm Cl^{-}} \to {\rm Cl_{2}} + 2\, {e^{-}}[/tex].
(Electrons travel from the solution to an electrode.)
[tex]2\, {\rm \overset{+1}{H}_{2} O} + 2\, {e^{-}} \to \overset{0}{\rm H}_{2} + 2\, {\rm O\overset{+1}{H}\!^{-}}[/tex].
(An electrode supply electrons to the solution to reduce some of the [tex]\rm H[/tex] atoms from [tex]\rm H_{2}O[/tex].)
In a DC circuit, electrons always enter the circuit from the negative terminal of the power supply and return to the power supply at the positive terminal.
The negative electrode is connected to the negative terminal of the power supply. Electrons from the power supply would flow into the solution through this electrode.
This continuous supply of electrons at the negative electrode would drive a reduction half-reaction. In this question, that corresponds to the reduction of water: [tex]2\, {\rm \overset{+1}{H}_{2} O} + 2\, {\rm e^{-}} \to \overset{0}{\rm H}_{2} + 2\, {\rm O\overset{+1}{H}\!^{-}}[/tex]. Hence, [tex]\rm H_{2}[/tex] would be produced at the negative electrode.
Based on the crystal- field strength cl-
1) Based on the crystal field strength, Cl ligand would give the longest d-d transition when complexed with Ti(III). as this is the weak field igand and would cause minimum splitting of d orbitals.
How to prepared sodium chloride solution in the laboratory.
hope it will help you
.
.
.
hope it will helps
A skydiver slows down from 65 m/s to 5 m/s by opening the parachute. If this
takes 0.75 seconds, what is the skydiver's acceleration?
A. 45 m/s2 up
B. 80 m/s2 up
C. 45 m/s2 down
D. 80 m/s2 down
Answer:
D. -80m/s^2
Explanation:
V = u + at
5 = 65 + a (0.75)
0.75a = -60
a = -60/0.75
a = -80m/s^2
Therefore, is decelerating at 80m/s^2
Answer:
[tex]\boxed {\boxed {\sf D. \ 80 \ m/s^2 \ down}}[/tex]
Explanation:
We are asked to find the acceleration of a skydiver. Acceleration is the change in velocity over the change in time, so the formula for calculating acceleration is:
[tex]a= \frac{v_f-v_i}{t}[/tex]
The skydiver was initially traveling 65 meters per second, then he slowed down to a final velocity of 5 meters per second. He slowed down in 0.75 seconds.
[tex]\bullet \ v_f = 5 \ m/s \\\bullet \ v_i= 65 \ m/s \\\bullet \ t= 0.75 \ s[/tex]
Substitute the values into the formula.
[tex]a= \frac{ 5 \ m/s - 65 \ m/s}{0.75 \ s}[/tex]
Solve the numerator.
[tex]a= \frac{-60 \ m/s}{0.75 \ s}[/tex]
Divide.
[tex]a= -80 \ m/s^2[/tex]
The acceleration of the skydiver is -80 meters per second squared or 80 meters per second squared down. The skydiver is slowing down or decelerating, so the acceleration is negative or down.
16.
are substances that facilitate the movement of electrons or electrical charge.
O A. Oxidizing agents
B. Solvents
O C. Electrolytes
O D. Reducing agents
A small object has a mass of 68.1 grams. When completely immersed in a graduated cylinder with a water level of 25.0mL the object causes the water level to rise to 43.3mL. What is the density of the object in g/mL?
Answer:
3.72
Explanation:
First you need the volume.
Final level = 43.3
Initial level = 25.0
Change in volume =18.3
So the density = mass / volume
mass = 68.1
vol = 18.3
density = 68.1 / 18.3
density = 3.72
Answer:
[tex]\boxed {\boxed {\sf 3.72 \ g/mL}}[/tex]
Explanation:
We are asked to find the density of a small object. Density is calculated using the following formula.
[tex]\rho= \frac{m}{v}[/tex]
The mass of the object is 68.1 grams.
The volume was found using water displacement. A known quantity of water was measured out (25.0 mL), then the object was added. The new water level was recorded (43.3 mL). The volume is the difference between the two water levels.
volume = final water level - initial water level volume = 43.3 mL - 25 mL = 18.3 mLNow we know the mass and the volume, so we can substitute the values into the formula.
[tex]\rho= \frac{ 68.1 \ g }{18.3 \ mL}[/tex]
[tex]\rho = 3.721311475 \ g/mL[/tex]
The original measurements of mass and water levels have 3 significant figures, so our answer must have the same. For the number we found, that is the hundredth place. The 1 in the thousandth place tells us to leave the 2 in the hundredth place.
[tex]\rho \approx 3.72 \ g/mL[/tex]
The density of the small object is approximately 3.72 grams per milliliter.
The difference between voltaic and electrolytic cells is that:
O A. voltaic cells generate electricity through a spontaneous reaction while electrolytic cells absorb electricity to drive a non-spontaneous reaction.
OB. electrolytic cells generate electricity through a spontaneous reaction while voltaic cells absorb electricity to drive a non-spontaneous reaction.
OC. None of these
D. electrolytic cells generate electricity through a non-spontaneous reaction while voltaic cells absorb electricity to drive a spontaneous reaction.
Answer:
c is answwe
Explanation:
none of these
The difference between voltaic and electrolytic cells is that voltaic cells generate electricity through a spontaneous reaction while electrolytic cells absorb electricity to drive a non-spontaneous reaction. option A is correct.
What are voltaic cells and electrolytic cells?Voltaic cells are spontaneous chemical reaction happens at which results in the generation or production of electrical energy or electricity. voltaic cell are made on basis on with modern-day batteries.
Electrolytic cells are the cells which do not generate electricity with the help of a chemical reaction, instead of it electrolytic cell creates a useful chemical reaction with the help of an externally applied potential or external applied energy difference.
Therefore, voltaic cells generate electricity through a spontaneous reaction while electrolytic cells absorb electricity to drive a non-spontaneous reaction. option A is correct.
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Compare and contrast the quantum mechanical model and Niels Bohr of the atom
Answer:
the quantum mechanical model VS. Neils Bohr of the atom
Explanation:
The Bohr model and quantum model are models that explain the structure of an atom. ... The key difference between Bohr and quantum model is that Bohr model states that electrons behave as particles whereas quantum model explains that the electron has both particle and wave behavior.
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)?
K1 and K2 are related algebraically because once the values are inserted into the equilibrium equation, both equations will yield a denominator of 100.
A piece of metal has a volume of 30.0cm3 and a mass of 252g. What is its density? what metal do you think this is?
Answer:
Explanation:
get density = D = m / V = 0.252 / 0.00003 = 8400 metal will be Cu => bronze 1. Determine the INTRAmolecular force for the following compounds: (nonpolar covalent, polar covalent ionic) CH4 ,CF4,CO2, NH3,NaCl,HI.
2. How did you determine the intramolecular force for these compounds?
need help asap..please
Explanation:
What you need to know.
hope it's helpful
A polar bond is when atoms have unequal attractions for electrons and so the sharing is unequal.
Electromagnetivity is the ability of an atom to attract electrons when atoms are in a compound.
To determine the electromagnetivity of an atom:
< 0.5 - Non-Polar
0.5 - 1.7 - Polar
Therefore, unequal sharing results in either a hydrogen or dipole bond.
Hydrogen bonding is just a special case of dipole-dipole interactions as hydrogen is partially positive in the molecule. When covalently bonded to a highly electronegative element, the hydrogen atom becomes so highly partial positive while the other so partial negative that a higher amount of interaction is obtain.However, keep in mind that hydrogen bonding can ONLY occur when hydrogen is covalently bonded to fluorine, oxygen and nitrogen.
A dipole-dipole interaction occurs between opposite partial charges in polar molecules. These attractions are generally weaker than hydrogen bonding.
London dispersion forces occurs in all bonds, as it's a temperorary attraction force when electrons in an atom occupy positions that form temporary dipoles. It's notable particularly in noble gases and it's the weakest of the intermolecular forces.
The elements present in a group of periodic table have
Similar chemical properties) Give reason and a
suitable element?
Answer:
group 1 elements(hydrogen,sodium,etc)
Explanation:
bexause if noticed all the element in the same group have the same eletron in thr outer most shell for example the group 1 elements are said to have 1 outermost elect ron which make them react so the same
How many moles of Cl− are in 5.76 mg of FeCl3?
Answer:
0.0061650760770388 mole
For centuries scientists found evidence that supports the theory of spontaneous generation. Which of the following
supported this theory?
A. The sun rising in the east and seeing in the west.
B. Maggots appearing on rotten meat.
C. The swan-next flask experiment.
D. All living things are made of cells.
Spontaneous generation theory is that living organisms can arise by non living things.
This theory follows the concept of abiogenesis where there is non living parent for a living child.
The appearance of maggots from rotten meat is the idea of abiogenesis, this creates a living organism with a dead parent.
The rotten piece of meat is a non living object but still maggots were formed from this.
Therefore the correct answer is B.
Answer:
a
Explanation:
