why is the Dna molecule able to open up and close?
Answer:
The breaking of the hydrogen bonds due to the force relieves the torsional stress stored in a double helix. As a result, the nucleotide strands rotate more freely about the axis of a helix and start unwinding. ... The DNA unzipping and the DNA unwinding result in a structural transformation from dsDNA to ssDNA.
Why doesn’t the KHP concentration have to be exactly 0.100M? Explain using complete sentences.
Answer:
The answer is in the explanation.
Explanation:
The KHP is an acid used as standard in titrations to find concentration of bases as NaOH.
The reaction that explain this use is:
KHP + NaOH → KNaP + H2O
where 1 mole of KHP reacts per mole of NaOH
That means, at equivalence point of a titration in which titrant is NaOH, the moles of KHP = Moles of NaOH added
With the moles of KHP = Moles of NaOH and the volume used by titrant we can find the molar concentration of NaOH.
The moles of KHP are obtained from the volume and the concentration as follows:
Volume(L)*Concentration (Molarity,M) = moles of KHP
If the concentration is more or less than 0.100M, the moles will be higher or lower. For that reason, we need to know the concentration of KHP but is not necessary to be 0.100M.
Out of a box of 46 matches, 22 lit on the first strike. What percentage of the matches in the box did not light on the first strike?
Answer: 52.17%
Explanation:
Number of matches in the box = 46
Number of matches that lit on the first strike = 22
Number of matches that did not light on the first strike = 46 - 22 = 24
Therefore, the percentage of the matches in the box did not light on the first strike will be:
= (Number of matches that did not light on the first strike / Number of matches in the box) × 100
= 24/46 × 100
= 52.17%
Therefore, the percentage of the matches in the box that did not light on the first strike is 52.17%.
as the balloon rises what happens to the external pressure
Answer:
As the ballon rises higher the atmospheric pressure will drop if the ballon is made of an elastic material,it will stretch to allow the gas inside it to expand
What is the mass, in grams, of one mole of any substance known as?
ОА.
atomic mass
OB.
molar mass
O C.
molecular weight
OD.
atomic number
Answer:
I think it's answer would be A
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Give the structural formula of CH3CH(CH3)CH3
In the structure, we essentially have a Carbon with 3 methyl groups and a hydrogen attached to it
Which atom is abundant on earth
Answer:
Oxygen
Explanation:
Oxygen is abundant on earth
There is 25.3 mL of the sulfuric acid solution; the sulfuric acid concentration is 2.30 M. Your base solution is 1.00 M. What is the volume in mL of base that is required to complete the neutralization of the acid
Answer:
The volume of the base is 0.05819·x L, where x is the number of moles of base that combines with one mole of sulfuric acid
Explanation:
The volume of the sulfuric acid, V = 25.3 mL = 25.3 × 10⁻³ L
The concentration of the sulfuric acid, c = 2.30 M
The concentration of the base, [tex]c_{base}[/tex] = 1.00 M
Let the mole ratio of the acid to base be 1 : x
The number of moles of sulfuric acid present, n = c × V
∴ n = 2.30 M/L × 25.3 × 10⁻³ L = 0.05819 moles
The number of moles of sulfuric acid present, n = 0.05819 moles
1 mole of sulfuric acid combines with x moles of base
Therefore, 0.05819 moles of sulfuric acid will combine with 0.05819·x moles of base
The number of moles of base, [tex]n_{base}[/tex] = 0.05819·x moles
Therefore, the volume of base, [tex]V_{base}[/tex] = [tex]n_{base}[/tex]/[tex]c_{base}[/tex]
∴ [tex]V_{base}[/tex] = 0.05819·x/1 ≈ 0.05819·x L
The volume of base, [tex]V_{base}[/tex] ≈ 0.05819·x L.
Which of the following is an example of a molecule?
A. A sodium atom forms a metallic bond with another sodium atom.
B. A hydrogen atom forms a covalent bond with a chlorine atom.
C. A sodium atom forms an ionic bond with a chlorine atom.
D. A sodium atom forms a metallic bond with another sodium atom.
Answer:
The answer is B. A hydrogen atom forms a convalent bond.........
Two glasses labeled A and B had equal amounts of water. Ted heated the water in one of the glasses. He then put two drops of food coloring into each of the two glasses. The table shows the time taken by the food coloring in the two glasses to spread out.
Which of the following statements is correct?
A - The water in Glass B was heated; therefore, the particles in Glass B have greater kinetic energy and move faster.
B - The water in Glass A was heated; therefore, the particles in Glass A have greater kinetic energy and move faster.
C - The water in Glass B was heated; therefore, the particles in Glass B move slower.
D - The water in Glass A was heated; therefore, the particles in Glass A move slower.
Answer:
The answer is A: The water in Glass B was heated; therefore, the particles in Glass B have greater kinetic energy and move faster.
Explanation:
Think about it, if you boil water, whatever you put in the water is going to move around faster than if you put something in standing water.
(PLEASE mark Brainliest!)
The water in Glass B was heated; therefore, the particles in Glass B have greater kinetic energy and move faster. The correct answer is A.
What is food coloring?Food coloring, or color additive, is any dye, pigment, or substance that imparts color when it is added to food or drink.
The food coloring we add to the water is pushed around by the water molecules. Since the molecules in warm water move around faster, the food coloring spreads out quicker in warm water than in cold water.
From the table, we can say that the water in glass B was heated by Ted and the molecules of food coloring spread out quickly in warm water and they have greater kinetic energy and move faster.
On the other hand, in glass A, the water is cold, so food coloring will not dissolve quickly.
Therefore, The water in Glass B was heated; therefore, the particles in Glass B have greater kinetic energy and move faster. The correct answer is A.
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How many moles are there in 2.3 x 1024 atoms of
sulfur?
Explanation:
The steps given in the question are incorrect.
Step 1 should be convert atoms to moles (n). Step 2 should be convert moles (n) to mass (m).
Step 1
Use dimensional analysis to convert the number of atoms to moles.
1 mole atoms = 6.022 × 10²³ atoms
n(Ag) = 2.3 × 10²⁴ Ag atoms × (1 mol Ag/6.022 × 10²³ Ag atoms) = 3.8193 mol Ag
Step 2
Convert the moles of Ag to mass.
mass (m) = moles (n) × molar mass (M)
n(Ag) = 3.8193 mol Ag
M(Ag) = atomic weight on the periodic table in g/mol = 107.868 g Ag/mol Ag
m(Ag) = 3.8193 mol × 107.868 g/mol = 412 g Ag = 410 g Ag rounded to two significant figures
The mass of 2.3 × 10²⁴ Ag atoms is approximately 410 g.
Answer:
[tex]\boxed {\boxed {\sf 3.8 \ moles \ of \ sulfur}}[/tex]
Explanation:
We are asked to convert a number of atoms to moles.
We can convert atoms to moles using Avogadro's Number, which is 6.022 × 10²³. This is the number of particles (atoms, molecules, formula units, etc.) in 1 mole of a substance. In this problem, the particles are atoms of sulfur. There are 6.022 ×10²³ atoms of sulfur in 1 mole of sulfur.
We use dimensional analysis to convert atoms to moles. This involves setting up ratios. Use Avogadro's Number and the underlined information to make a ratio.
[tex]\frac {6.022 \times 10^{23} \ atoms \ S}{1 \ mol \ S}[/tex]
We are converting 2.3 ×10²⁴ atoms of sulfur to moles, so we multiply by this value.
[tex]2.3 \times 10^{24} \ atoms \ S *\frac {6.022 \times 10^{23} \ atoms \ S}{1 \ mol \ S}[/tex]
Flip the ratio. It is equivalent, but it allows the units of atoms of sulfur to cancel.
[tex]2.3 \times 10^{24} \ atoms \ S *\frac {1 \ mol \ S}{6.022 \times 10^{23} \ atoms \ S}[/tex]
[tex]2.3 \times 10^{24} *\frac {1 \ mol \ S}{6.022 \times 10^{23} }[/tex]
[tex]\frac {2.3 \times 10^{24} }{6.022 \times 10^{23} } \ mol \ S[/tex]
[tex]3.819329127 \ mol \ S[/tex]
The original measurement of atoms (2.3 ×10²⁴) has 2 significant figures, so our answer must have the same. For the number we calculated that is the tenths place. The 1 in the hundredths place to the right (3.819329127) tells us to leave the 8 in the tenths place (3.819329127).
[tex]3.8 \ mol \ S[/tex]
2.3 ×10²⁴ atoms of sulfur is equal to approximately 3.8 moles of sulfur.
True or false..
(A) Burning of magnesium ribbon is physical change
Answer:
False because it is chemical change
Formal charge is calculated by assigning each atom _____ the bonding electrons that it shares. Oxidation number is determined by assigning all the shared electrons of a particular bond to the atom with the _____ electronegativity. Multiple choice question. half; higher half; lower all; lower all; higher
Answer:
A). half, higher
Explanation:
The Formal charge is elaborated as the 'allocated charge to a molecules' atom' on the basis of the assumption that the electrons present in the chemical bond are equally split among the atoms. It is estimated by 'halving the no. of bonding electrons that encircle the atom.
While Oxidation number is characterized as the 'hypothetical charge of an atom that is present within a molecule.' It is also defined as 'the actual number of lost or gained electrons or the rate at which the electrons are gained or lost by an atom to develop a chemical bond along with the other atom.' It is calculated by allocating or sharing the electrons having the higher electronegativity belonging to a specific bond with the other. Thus, option A is the correct answer.
what happens to bases when mixed with acids?
They form salt + water.
and the rxn is known as neutralisation rxn
Answer:
When an acid and a base are placed together, they react to neutralize the acid and base properties, producing a salt. Acid-base reactions that do not occur in water usually also produce salts, but they may also produce complex ions.
Helpful Link:
https://sciencing.com/happens-acid-base-combined-5132830.html
a 20.5g sample of cleaning detergent contains 8.61g of NH40H.CALCULATE the percentage composition of nitrogen in the cleaning detergent sample
Answer:
The mass percentage composition of nitrogen in the sample of the cleaning detergent is approximately 16.78%
Explanation:
The given mass of the sample of the cleaning detergent, m₁ = 20.5 g
The mass of the ammonium hydroxide, NH₄OH in the detergent, m₂ = 8.61 g
The molar mass of NH₄OH = 35.04 g/mol
The molar mass of nitrogen, N = 14.01 g/mol
Therefore, the mass, m₃ of nitrogen, N, in 8.61 g of ammonium hydroxide, NH₄OH, is found as follows;
m₃ = (14.01/35.04) × 8.61 g = (402,087/118,800) g ≈ 3.44 g
The mass of nitrogen, N, in the ammonium hydroxide, NH₄OH, contained in the 20.5 g sample of the cleaning agent, m₃ ≈ 3.44 grams
The percentage composition of nitrogen in the sample of the cleaning detergent, %N is given as follows;
[tex]\% Composition = \dfrac{Mass \ of \ component}{Total \ mass \ of \ cleaning \ detergent} \times 100[/tex]
Therefore;
%N ≈ ((3.44 g)/(20.5 g)) × 100 ≈ 16.78 %
The percentage composition of nitrogen, %N ≈ 16.78%.
PLZ HELP ME
Which of these is an example of an example factor which affects the earths climate?
A - Decrease in the suns energy.
B - Warm and cold ocean currents.
C - Increase in atmospheric dioxide.
D - Release of dust during volcanic eruption
Answer:
D- Release of dust during volcanic eruption
Explanation:
During major explosive eruptions huge amounts of volcanic gas, aerosol droplets, and ash are injected into the stratosphere. Injected ash falls rapidly from the stratosphere -- most of it is removed within several days to weeks -- and has little impact on climate change. But volcanic gases like sulfur dioxide can cause global cooling, while volcanic carbon dioxide, a greenhouse gas, has the potential to promote global warming.
answer:
a - decrease in the suns energy.
explanation:
although the other options do discuss climate, temperature, etc., the sun DIRECTLY influences the earth's climate and would most likely affect it on a larger scale. for example, warm and cold ocean currents would affect the temperature of the ocean and could touch bay cities or islands, but they would not dictate the overall climate of the earth :)
♡ hopefully my reply helped you come to an answer~ please keep in mind that my response is purely that... MY response! i still have lots to learn, so please correct/educate me if you have found otherwise ♡
What is the mass of the block of iron that has 10 cm 5 cm and 2 centimeters
Answer:
787.4g
Explanation:
The dimensions of the iron block is given as follows;
L = 10cm, B = 5cm, H = 2cm
Volume = L × B × H
Volume = 10 × 5 × 2
Volume = 100cm³
Density of iron metal = 7.874 g/cm³
Using the formula;
Density = mass/volume
Mass = density × volume
Mass = 7.874 × 100
Mass of iron = 787.4g
Explain whether changing the ratio of baking soda and vinegar changes the amount of carbon dioxide produced. Include the evidence you used to reach your conclusion.
On changing the ratio of baking soda and vinegar changes the amount of carbon dioxide produced is true, because each species will depends on both reactants.
What is chemical reaction?Chemical reaction between baking soda and vinegar is shown below in the attached image in which the formation of carbon dioxide, water and sodium acetate takes place. So the formation of carbon dioxide depends on the baking soda and baking soda reacts with vinegar to form sodium acetate so change in the ratio will changes the amount of carbon dioxide.
Hence on changing the ratio of reactants and vinegar changes the amount of carbon dioxide.
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Mass of A = 320 g
Volume of A= 64 cm3
A
Density of B = 3 g/cm3
Volume of B = 27 cm3
(Not drawn to scale)
11
22. What is the density of cube A?
A) 0.2 g/cm3 B) 5.0 g/cm3
C) 12.8 g/cm D) 64.0 g/cm3
Answer:
Mass of A=320g
Volume of A=64cm3
Density of B =3g/cm3
Volume of B = 27 cm3
(Not drawn to scale)
and the density of cube A =5.0g/cm3
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The density of the object that has been labelled as A from the calculation is 5.0 g/ [tex]cm^3[/tex]. Option B
What is the density?
Density is a physical property of matter that measures how much mass is contained within a given volume.
Density is a fundamental property of matter that describes how mass is distributed within a given volume. It is a useful parameter in various scientific, engineering, and everyday applications.
We know that;
Density = Mass/Volume
= 320 g/64 [tex]cm^3[/tex]
= 5.0 g/ [tex]cm^3[/tex] as seen here
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help pls I really need the answer I will brainlest
Answer:
Latitude: the angular distance of a place north or south of the earth's equator, or of a celestial object north or south of the celestial equator, usually expressed in degrees and minutes. (Left to right)
Longitude: the angular distance of a place east or west of the meridian at Greenwich, England, or west of the standard meridian of a celestial object, usually expressed in degrees and minutes. (Up and down)
Aluminum hydroxide containing medicine is used for gastric why
Answer:
Aluminum Hydroxide, Magnesium Hydroxide are antacids used together to relieve heartburn, acid indigestion, and upset stomach. They may be used to treat these symptoms in patients with peptic ulcer, gastritis, esophagitis, hiatal hernia, or too much acid in the stomach (gastric hyperacidity).
Answer:
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Answer:
Cl2(g) + H2O <–> HOCl + H+ + Cl-
Chlorine is the most popular way for the sterilization of water.
Cl2 + H2O → HOCl + HCl
Oxide of nitrogen that is acidic
Answer:
Nitrogen oxides are used in the production of nitric acid, lacquers, dyes, and other chemicals. Nitrogen oxides are used in rocket fuels, in the nitrification of organic chemicals, and in the manufacture of explosives.
Explanation:
What word chemical equation describes Cavendish’s experiment with zinc?
WILL GIVE BRANLIEST !!!!!!!!!!!!!!!!!!
Answer:
The reaction between zinc and HCl is given by the symbolic equation
Zn + HCl → ZnCl2 + H2.
When 38^88Sr decays to 34^84Kr, a(n) ______________ is emitted
Answer:
The correct answer is - alpha particle and positron.
Explanation:
In this question, it is given that, 38^88Sr decays to 34^84Kr, which means there is an atomic number decrease by 4, 38 to 34, and atomic mass decreases by 4 as well 88 to 84.
A decrease in the atomic mass is possible only when there is an emission of the alpha particle as an alpha particle is made of 2 protons and 2 neutrons. If an atom emits an alpha particle, there is a change in atomic number as it decreases by two, and its mass number decreases by four.
So after the emission of an alpha particle, the new atom would be
38^88Sr=> 36^84X => 34^84Kr
so there is also two positron emission that leads to decrease in atomic number by one with each emission:
38^88Sr=> 2^4He+ 36^84X => 36^84X + 2(1^0β+) => 34^84Kr
Positron decay is the conversion of a proton into a neutron with the emission of a positron that causes the atomic number is decreased by one, which causes a change in the elemental identity of the daughter isotope.
value of MA is always lesser thàn 1 why?
Answer:
because the load arm is greater than the effort arm. As we know that when the load arm is greater than the effort arm, the mechanical advantage will always be lesser than one, which results in gain in speed
What is the pressure in atm exerted by 1.8 g of H2 gas exert in a 4.3 L balloon at 27ºC? R = 0.821(L*atm) / (mol*K)
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The pressure in atm exerted by 1.8 g of H₂ gas exert in a 4.3 L balloon at 27ºC is 5.12 atm
What is Ideal gas law ?The ideal gas law (PV = nRT) relates the macroscopic properties of ideal gases. An ideal gas is a gas in which the particles (a) do not attract or repel one another and (b) take up no space (have no volume).
Let's convert grams to moles (via molar mass).
Molar Mass (H₂) : 2 (1.008 g/mol)
Molar Mass (H₂) : 2.016 g/mol
1.8 grams H₂ 1 mole
---------------------- x ---------------------- = 0.893 moles H₂
2.016 grams
The Ideal Gas Law equation looks like this:
PV = nRT
In this equation,
P = pressure (atm) V = volume (L) n = moles R = Ideal Gas Constant (0.0821 L*atm/mol*K)T = temperature (K)After converting Celsius to Kelvin, you can put the given values into the equation and simplify to find the pressure.
P = ? atm R = 0.0821 L*atm/mol*K
V = 4.3 L T = 27 °C + 273.15 = 300.15 K
n = 0.893 moles
PV = nRT
P (4.3 L) = (0.893 moles) (0.0821 L*atm/mol*K)( 300.15 K)
P (4.3 L) = 22.0021
P = 5.12 atm
Therefore, The pressure in atm exerted by 1.8 g of H₂ gas exert in a 4.3 L balloon at 27ºC is 5.12 atm
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How many Sodium (NA) Atoms are in Methylene?
Answer:
No Sodium(Na) in methylene
Explanation:
Methylene is an organic compound
In an exothermic reaction, heat is
released into the surroundings. How does this affect entropy?
particles in the surroundings move slower and have decreased entropy.
• B. The particles in the surroundings move faster and have increased entropy.
•C. The particles in the surroundings move
surroundings move slower and have increased entropy.
• D. The entropy is not affected by this.
Answer:
B. the particles in the surroundings move faster and have increased entropy
Explanation:
An exothermic process releases heat, causing the temperatures of the surroundings to increase. Entropy increases as temperature increases. Since an exothermic reaction releases heat to the surroundings, molecules in the surroundings will begin to move faster because they will absorb more energy, which increases their kinetic energy. An increase in temperatures means that the particles of the surroundings have greater kinetic energy. The faster moving particals have more disorder than particles that are moving more slowly at a lower temperature. Entropy is interpreted as the degree of disorder/randomness.
please solve this question
Answer:
b) it gets accumulated in the respiratory system which then halts or slows down the supply of oxygen to the brain hence leading to death
