Answer:
In Watson and Crick's model, the two strands of the DNA double helix are held together by hydrogen bonds between nitrogenous bases on opposite strands. Each pair of bases lies flat, forming a "rung" on the ladder of the DNA molecule.
Explanation:
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Identify the compound with the lowest dipole moment. Identify the compound with the lowest dipole moment. CH3CH2CH3 CH3OCH3 CH3CHO CH3OH CH3CN
Answer:
CH3CH2CH3
Explanation:
Dipole moment is the measure of the polarity of a chemical bond. It is the extent of charge separation in a molecule.
Dipole moment is the product of the magnitude of charge and the distance separating the charges from each other.
The molecule having the lowest dipole moment among the options is the molecule that has the least polarity. The least polar molecule among the options is CH3CH2CH3, it has no polar bonds in its structure.
We have that for the Question "Identify the compound with the lowest dipole moment. Identify the compound with the lowest dipole moment. CH3CH2CH3 CH3OCH3 CH3CHO CH3OH CH3CN "
it can be said that
[tex]CH_3CH_2CH_3 have the lowest dipole moment[/tex]From the question we are given
CH3CH2CH3
CH3OCH3
CH3CHO
CH3OH
CH3CN
Generally alkanes have the lowest dipole moment, they have C-H bond which are non polar.
Therefore,
[tex]CH_3CH_2CH_3[/tex] have the lowest dipole moment
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Why is iodine always Used in a solution containing excess I2
Answer:
If a standard iodine solution is used as a titrant for an oxidizable analyte, the technique is iodimetry. If an excess of iodide is used to reduce a chemical species while simultaneously forming iodine.
Iodine always used in a solution excess KI is given to aid in the solubilization of free iodine, which would be insoluble in clean water during normal circumstances.
What is Iodine?
Iodine is a kind of element which are mainly used in iodometry titration. It can be represented by I.
What is solution?A solution would be a homogenous mixture of two components, usually a solute as well as a solvent.
Iodimetry would be a technique that uses a standard iodine solution as a titrant for such an oxidizable analyte. When an excessive amount of iodide is used to decrease a chemical while somehow producing iodine.
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Please write the right question. I’ll mark as brainliest if it’s right
Answer:
The correct answer is - A. alkane and E. Branched.
Explanation:
Alkane is saturated hydrocarbons that are combined with a single bond they can be either linear, branched, or cyclic hydrocarbons. A branched-chain or branched compound is a compound that has alkyl groups bonded to its central carbon chain.
Branched alkanes contain only carbon atoms and hydrogen atoms bonded with these carbon atoms in different branches, with carbons connected to other carbons by single bonds only, but the molecules contain branches.
Use the following information to calculate the concentration, Ka and pka for an unknown monoprotic weak acid. (8 pts.) 20.00 mL
Volume of unknown weak acid used : 20.00 mL Total volume of 0.20 M NaOH required to reach the equivalence point: 18.50 mL Initial pH of the weak acid 2.87
Answer:
Concentration: 0.185M HX
Ka = 9.836x10⁻⁶
pKa = 5.01
Explanation:
A weak acid, HX, reacts with NaOH as follows:
HX + NaOH → NaX + H2O
Where 1 mole of HX reacts with 1 mole of NaOH
To solve this question we need to find the moles of NaOH at equivalence point (Were moles HX = Moles NaOH).
18.50mL = 0.01850L * (0.20mol / L) = 0.00370 moles NaOH = Moles HX
In 20.0mL = 0.0200L =
0.00370 moles HX / 0.0200L = 0.185M HX
The equilibrium of HX is:
HX(aq) ⇄ H⁺(aq) + X⁻(aq)
And Ka is defined as:
Ka = [H⁺] [X⁻] / [HX]
Where [H⁺] = [X⁻] because comes from the same equilibrium
As pH = 2.87, [H+] = 10^-pH = 1.349x10⁻³M
Replacing:
Ka = [H⁺] [H⁺] / [HX]
Ka = [1.349x10⁻³M]² / [0.185M]
Ka = 9.836x10⁻⁶
pKa = -log Ka
pKa = 5.01What is the molar mass of Na2SO4?
O A. 142.04 g/mol
O B. 71.05 g/mol
O c. 238.22 g/mol
O D. 94.04 g/mol
Answer: A. 142.04 g/mol
Explanation:
What must happen for ice to melt at a given pressure?
A. The average kinetic energy of the water molecules must decrease.
B. Thermal energy must be transferred to the ice from its
surroundings.
C. The orderliness of the water molecules must decrease.
D. Thermal energy must be transferred from the ice to its
surroundings.
Answer:
D
Explanation:
thermal energy must be transferred from the ice to it's surroundings
Thermal energy is the heat and energy present in the system. The thermal energy must be dissipated from ice to the surroundings to melt and produce liquid. Thus, option D is correct.
What is thermal energy?Thermal energy is present in any substance in the form of energy and heat that depends on kinetic energy, orderliness, randomness, temperature, etc. It is passed from a substance to the surrounding at a lesser temperature.
The ice can melt into a liquid when it loses its thermal energy and heat to the surrounding with increased kinetic energy and releases the temperature to the area with a temperature less than the ice.
Therefore, the heat from ice will get dissipated to the outer environment to melt.
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15. Triglycerides, waxes, and steroids are all ___ lipids because they contain only carbon, hydrogen, and oxygen
A. simple
B. methyl esters
C. complex
D. long-chain compounds
Answer:
A. simple
Explanation:
While studying abroad in France, you offer to bake your grandmother's famous cookies for other students in your program.
have a recipe which calls for 3.95 lb of flour, but, of course, in France you will need to purchase flour in kilograms. How m
kilograms of flour does the recipe call for?
3.95 lb =
Answer:
The mass of the flour required to prepare the cookies is 1.8 kg.
Explanation:
The flour required to prepare the cookies is 3.95 lb.
1 lb = 0.454 kg
So, 3.95 lb = 3.95 x 0.454 kg = 1.8 kg
So, the mass of the flour required to prepare the cookies is 1.8 kg.
12 + NaF --> Nal + F2 What is the coefficient of Nal when this equation is
balanced? *
Answer:
Explanation:
NaL
Difluorine - F2
Molar Mass Bond Polarity F₂ Fluorine Gas Fluorine
Products
Sodium Fluoride - NaF
Molar Mass Bond Polarity Oxidation State Floridine Sodium Monofluoride Naf
L2
What is the wavelength of light that has a frequency of 3.7 x 1014 Hz? Show all work!!!
Answer:
Explanation:
Speed of light = Frequency * Wavelength
Speed of light is 3*10^8 m/s
Wavelength = Speed / Frequency = 3*10^8 / 3.7*10^14
= 8.11*10^(-7) m
= 811 nanometer
The wavelength of light will be
What is wavelength?The wavelength of such a periodic wave would be the interval in which the shape of the wave repeats.
Calculation of wavelength of light
It is given that,
frequency = 3.7 x [tex]10^{14}[/tex] Hz
Speed of light = 3 × [tex]10^{8}[/tex] m/s
frequency × wavelength = speed of light.
wavelength = speed of light / frequency
wavelength = 3 × [tex]10^{8}[/tex] m/s / 3.7 x [tex]10^{14}[/tex] Hz
wavelength = 0.81 × [tex]10^{-7}[/tex] m
wavelength = 8.1 × [tex]10^{-7}[/tex]
Therefore, wavelength of light will be 8.1 × [tex]10^{-7}[/tex].
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How much energy does an X-ray with an 8 nm (8 x 10-9m) wavelength have?
A. 1.99 x 10-25 J
B. 3.33 x 1016 J
C. 2.48 x 10-17 j
D. 8.28 x 10-26 J
Answer:
it would be option C
Explanation:
Speed of light = 3×10^8m/s
Planck's constant = 6.626×10^-34 Js
Wavelength = 8 x 10^-9 m
Energy = [(3×10^8) * (6.626×10^-34)] / 8 x 10^-9
Energy = [19.878×10^(8-34)] / 8 x 10^-9
Energy = 2.48475 × 10^(-26+9)
Energy = 2.48×10^-17 J
What volume in mL of 0.220 M HBr solution is required to produce 0.0130 moles of HBr?
Answer: A volume of 59 mL of 0.220 M HBr solution is required to produce 0.0130 moles of HBr.
Explanation:
Given: Moles = 0.0130 mol
Molarity = 0.220 M
Molarity is the number of moles of solute present in liter of a solution.
[tex]Molarity = \frac{moles}{volume (in L)}[/tex]
Substitute the values into above formula as follows.
[tex]Molarity = \frac{moles}{volume (in L)}\\0.220 M = \frac{0.0130 mol}{Volume (in L)}\\Volume (in L) = 0.059 L[/tex]
As 1 L = 1000 mL
So, 0.059 L = 59 mL
Thus, we can conclude that a volume of 59 mL of 0.220 M HBr solution is required to produce 0.0130 moles of HBr.
A 15.0 mL urine from a dehydrated patient has a density of 1.019g/mL. What is the mass of the sample, reported in mg?
Answer:
Mass of sample in mg = 15,285 mg
Explanation:
Given:
Volume of urine sample = 15 ml
Density of sample = 1.019 g/ml
FInd:
Mass of sample in mg
Computation:
Mass = density x volume
Mass of sample in mg = Volume of urine sample x Density of sample
Mass of sample in mg = 1.019 x 15
Mass of sample in mg = 15.285 gram
Mass of sample in mg = 15.285 x 1,000
Mass of sample in mg = 15,285 mg
Molecule contains carbon, hydrogen and sulfur atoms. When a sample of 0.535g of this compound is burnt in oxygen, 1.119 g of CO2and 0.229 gof H2O and 0.407g of SO2are obtained.
Calculate its empirical formula.
Answer:
The empirical formula is, C4H4S
Explanation:
Number of moles of carbon = 1.119 g/ 44g/mol = 0.025 moles
Mass of Carbon= 0.025 moles × 12 g/ mole = 0.3 g
Number of moles of hydrogen = 0.229/18g/mol × 2 = 0.025 moles
Mass of hydrogen = 0.025 moles × 1 = 0.025 g
Number of moles of sulphur = 0.407g/ 64 g/mol = 0.0064 moles
Mass of sulphur= 0.0064 moles ×32 = 0.2 g
Now we obtain the mole ratios by dividing through by the lowest ratio.
C- 0.025 moles/ 0.0064 moles, H- 0.025 moles/ 0.0064 moles, S- 0.0064 moles/0.0064 moles
C4H4S
1 What direction do
molecules move in?
Answer:
The majority of the molecules move from higher to lower concentration, although there will be some that move from low to high. The overall (or net) movement is thus from high to low concentration.
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Calculate the number of representative particles of 0.0391 mol Neon gas.
i need help ASAP !
Answer:
2.35 × 10²² particles
Explanation:
To get the number of particles in a substance, we multiply the number of moles (n) of that substance by Avogadro's number (nA).
That is, we say;
number of atoms = n × 6.02 × 10²³
In this question, Neon gas is said to have 0.0391 moles. The number of atoms in that field.
number of particles = 0.0391 × 6.02 × 10²³
number of particles = 0.235 × 10²³
number of particles = 2.35 × 10²² particles
How many grams of Al2O3 is extracted from 250. g of FeO?
Answer:
[tex]m_{Al_2O_3}=118.27gAl_2O_3[/tex]
Explanation:
Hello there!
In this case, if we consider the following chemical reaction, whereby Al2O3 is produced from Al and FeO:
[tex]3FeO+2Al\rightarrow 3Fe+Al_2O_3[/tex]
Thus, since there is 3:1 mole ratio of FeO to Al2O3, it turns out feasible for us to use their molar masses, 71.844 g/mol and 101.96 g/mol respectively, to obtain the grams of the latter as follows:
[tex]m_{Al_2O_3}=250.gFeO*\frac{1molFeO}{71.844gFeO}*\frac{1molAl_2O_3}{3molFeO} *\frac{101.96gAl_2O_3}{1molAl_2O_3}\\\\m_{Al_2O_3}=118.27gAl_2O_3[/tex]
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Cesium-137 is part of the nuclear waste produced by uranium-235 fission. The half-life of cesium-137 is 30.2 years. How much time is required for the activity of a sample of cesium-137 to fall to 9.32 percent of its original value
Answer:
t(9.32% remaining) = 203 yrs (3 sig. figs.)
Explanation:
All radioactive decay follows a 1st order decay profile. This is defined by the expression ...
A =A₀e^-k·t
A = final activity = 9.32%
A₀ = initial activity = 100%
e = base of natural logs
k = rate constant = 0.693/t(1/2) = (0.693/30.2) yrs⁻¹ = 0.023 yrs⁻¹
t = time of decay = ln(A/A₀)/-k = ln(9.32%/100%)/-0.023 yrs⁻¹
= 203.286637 yrs (calc. ans.)
≅ 203 yrs (3 sig. figs.)
The drugs Prilosec and Nexium both contain the same active ingredient. Nexium contains a single enantiomer, but Prilosec is a racemic mixture. Which of the following is probably true regarding 20 mg doses of the two different drugs?
a. both drugs will be equally effective
b. both drugs can be prepared using the same synthetic procedure
c. Nexium will be more effective than Prilosec
d. Prilosec will be more effective than Nexium
Answer:
both drugs will be equally effective
Explanation:
A racemic mixture is a substance that contains a 50/50 mixture of the (+) and (-) enantiomers of an optically active compound.
It is important to note that even if a drug occurs as a racemic mixture, only the biologically active enantiomer will interact with the substrate on which the drug acts. The other enantiomer present is just irrelevant. Similarly, its presence does not affect the biological activity of the active enantiomer.
Hence, both Prilosec and Nexium are both equally effective.
identify the organ system pictured below and state two functions of this system in the body
Answer:
skeletal system
Explanation:
to create and fliter blood and provide frame-work to the human body and support
Express as ordinary numbers.
3 x 10^0 =
Answer:
the answer is 3
Explanation:
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A transition metal in the fourth period from the following list : Cu, O , Pr, Ag
Answer:
Cu
Explanation:
Groups 3 - 12 (or groups IIA - IIB) of the periodic table contain transition elements. Transaction elements start from period four (4) of the periodic table. The phrase alludes to the fact that the d sublevel is filling at a lower main energy level than the s sublevel that came before it.
The transition elements' arrangement is inverted from the fill order, with the 4 s filled prior to the actual 3 d begins. The transition elements are commonly referred to as transition metals since they are all metals. They are less reactive than the metals in Groups 1 and 2 and have normal metallic characteristics.
From the options given Cu is the only transition metal in the fourth period on the periodic table.
Look at picture please
Answer:
Keep temperature constant and increase the pressure of the reaction. The rate of reaction increases.
Explanation:
First of all, the question is asking us to design an experiment to investigate the effect of pressure on the rate of reaction hence the pressure can not be held constant since it is the variable under investigation. This eliminates the first option.
Secondly, increasing the pressure of the reaction means that particles of the gas collide more frequently leading to a greater number of effective collisions and a consequent increase in the rate of reaction according to the collision theory.
Hence the answer above.
Air bags are activated when a severe impact causes a steel ball to compress a spring and electrically ignite a detonator cap. This causes sodium azide (NaN3) to decompose explosively according to the following reaction. 2 NaN3(s) --> 2 Na(s) 3 N2(g) What mass in grams of NaN3(s) must be reacted in order to inflate an air bag to 79.5 L at STP
Answer:
154 g
Explanation:
Step 1: Write the balanced decomposition equation
2 NaN₃(s) ⇒ 2 Na(s) + 3 N₂(g)
Step 2: Calculate the moles corresponding to 79.5 L of N₂ at STP
At STP, 1 mole of N₂ occupies 22.4 L.
79.5 L × 1 mol/22.4 L = 3.55 mol
Step 3: Calculate the number of moles of NaN₃ needed to form 3.55 moles of N₂
The molar ratio of NaN₃ to N₂ is 2:3. The moles of NaN₃ needed are 2/3 × 3.55 mol = 2.37 mol.
Step 4: Calculate the mass corresponding to 2.37 moles of NaN₃
The molar mass of NaN₃ is 65.01 g/mol.
2.37 mol × 65.01 g/mol = 154 g
Name the parts of an electromagnet
Answer:
The iron core, copper wire, and an electricity source.
Explanation: Me
Read excerpt and answer 3 questions I’ll mark brainliest. Pls thank you
Answer:
please also share the excerpt
Explanation:
Thank you
1. Complete the following chart for the following atoms:
Element
Mass
number
Number of
electrons
Number of
neutrons
Atomic
Number
(number of
protons)
Potassium
16
56
26
What is the atomic symbol (the nuclide) for the isotope with 15 protons and 16
neutrons? Your answer must be in the form shown:
AX
You must show the correct numbers for A and Z
and have the correct symbol (Z). (3 points)
Explanation:
If there are 15 protons, 15 nuclear particles of unit positive charge, then
Z
=
15
. Now
Z
≡
the atomic number
, and you look at your copy of the Periodic Table, and you find that for
Z
=
15
, the element phosphorus is specified.
But we are not finished. Along with the 15 defining protons, there are also 16 neutrally charged, massive nuclear particles, 16 neutrons, and the protons and neutrons together determine the atomic mass. The isotope is thus
31
P
, which is almost 100% abundant, and an important nucleus for
NMR spectroscopy.
Over time, rocks break down into sediment by wind, water, ice, and/or gravity. This process is commonly referred to as
chemical change
Answer:
Explanation:
Chemical change
The sp of strontium carbonate, SrCO3, is 5.60×10−10 . Calculate the solubility of this compound in g/L.
Answer:
3.50 × 10⁻³ g/L
Explanation:
Step 1: Make an ICE chart for the solution of SrCO₃
"S" represents the molar solubility.
SrCO₃(s) ⇄ Sr²⁺(aq) + CO₃²⁻(aq)
I 0 0
C +S +S
E S S
The solubility product constant (Ksp) is:
Ksp = [Sr²⁺] [CO₃²⁻] = S²
S = √Ksp = √5.60 × 10⁻¹⁰ = 2.37 × 10⁻⁵ M
Step 2: Convert "S" to g/L
The molar mass of SrCO₃ is 147.63 g/mol.
2.37 × 10⁻⁵ mol/L × 147.63 g/mol = 3.50 × 10⁻³ g/L