Answer:
Suppose that you add 29.2 g of an unknown molecular compound to 0.250 kg of benzene, which has a K f of 5.12 oC/m. With the added solute, you find that there is a freezing point depression of 2.78 oC compared to pure benzene. What is the molar mass (in g/mol) of the unknown compound
Explanation:
The mass of nonvolatile solute added is ---- 29.2g
The mass of solvent benzene is ---- 0.250kg = 250g
The Kf value of benzene is ---- 5.12^oC/m.
Depression in the freezing point of the solution is --- 2.78^oC.
What is the molar mass of the unknown solute?
[tex]The depression in freezing point = Kf * molality of the solution\\molality of the solution = \frac{mass of solute}{molar mass of solute}*\frac{1}{mass of solvent in kg}[/tex]
Substitute the given values in this formula to get the molar mass of unknown solvent:
[tex]molality=\frac{29.2g}{M} * \frac{1}{0.250kg} \\depression in freezing point:\\2.78^oC=5.12^oC/m * \frac{29.2g}{M} * \frac{1}{0.250kg} \\\\=>M=5.12^oC/m * \frac{29.2g}{2.78^oC} * \frac{1}{0.250g} \\\\\\=>M=215.1g/mol[/tex]
Hence, the molar mass of unknown solute is --- 215g/mol.
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.
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:
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
2KClO3 (s)⇄2KCl (s)+ 3O2 (aq) equilibrium constant
Answer: The equilibrium constant for the given chemical reaction is [tex][O_2]^3[/tex]
Explanation:
The equilibrium constant is defined as the ratio of the concentration of the products to the concentration of reactants each raised to the power of their stoichiometric coefficients.
The concentration of all the solids and liquids are considered to be 1 in the expression of equilibrium constant
For the given chemical equation:
[tex]2KClO_3(s)\rightleftharpoons 2KCl(s)+3O_2(aq)[/tex]
The expression of equilibrium constant follows:
[tex]K_{eq}=[O_2]^3[/tex]
Hence, the equilibrium constant for the given chemical reaction is [tex][O_2]^3[/tex]
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.)
state the purpose of Watson and crick DNA structure experiment
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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is it a physical or chemical change when a candle is lit
describe what it would be like to be an atom
Explanation:
An atom consists of two regions. The first is the tiny atomic nucleus, which is in the center of the atom and contains positively charged particles called protons and neutral, uncharged, particles called neutrons. ... Most atoms contain all three of these types of subatomic particles—protons, electrons, and neutrons.
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
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.
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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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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What type of reaction is the following
chlorine +
potassium nitride
- nitrogen
+
potassium chloride
Explanation:
Answer
Open in answr app
Correct option is
A
Precipitation reaction
B
Double displacement reaction
Balanced equation for the reaction is:
KCl(s)+AgNO3(aq)→AgCl(s)+KNO3(aq)
It is a double displacement reaction as both reactants exchange ions to form new products. Also, it is a precipitation reaction as white precipitates of silver chloride(AgCl) are formed.
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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Calculate the molarity of a potassium hydroxide solution if 25.0 ml of this solution was completely neutralized by 23.3 ml of 0.506 M sulfuric acid.
Answer: 0.943 M of potassium hydroxide solution is required.
Explanation:
A neutralization reaction is defined as the reaction in which an acid reacts with a base to form a salt and water molecule.
To calculate the molarity of potassium hydroxide, the equation used is:
[tex]n_1M_1V_1=n_2M_2V_2[/tex] ........(1)
where,
[tex]n_1, M_1\text{ and }V_1[/tex] are the n-factor, molarity and volume of acid that is [tex]H_2SO_4[/tex]
[tex]n_2, M_2\text{ and }V_2[/tex] are the n-factor, molarity and volume of the base that is KOH
We are given:
[tex]n_1=2\\M_1=0.506M\\V_1=23.3mL\\n_2=1\\M_2=?M\\V_2=25.0mL[/tex]
Putting values in equation 1, we get:
[tex]2\times 0.506\times 23.3=1\times M_2\times 25.0\\\\M_2=\frac{2\times 0.506\times 23.3}{1\times 25.0}\\\\M_2=0.943M[/tex]
Hence, 0.943 M of potassium hydroxide solution is required.
How is a bacterium cell different from a human cell?
Answer:
Human cells are eukaryotic which means they are more complicated, bacteria cells are prokaryotic which means they are simpler
Explanation:
Hope this helps
Which commercial technology commonly uses plasmas?
a radio
a race car
a television
a microwave oven
Answer:
A television is commercial technology commonly uses plasmas.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.
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.
To what Celsius temperature does 750. mL of gas originally at −12°C need to be heated to bring the volume to 2.10 L?
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Name the parts of an electromagnet
Answer:
The iron core, copper wire, and an electricity source.
Explanation: Me
Calculate the mass of hydrogen formed when 26.98 g of aluminum reacts with excess hydrochloric acid according to the following balanced chemical equation: 2 Al + 6 HCl → 2 AlCl3 + 3 H2
Answer: The mass of hydrogen formed when 26.98 g of aluminum reacts with excess hydrochloric acid according to the given balanced equation is 3.03 g.
Explanation:
The given balanced reaction equation is as follows.
[tex]2Al + 6HCl \rightarrow 2AlCl_{3} + 3H_{2}[/tex]
Here, the mole ration of Al and hydrogen produced is 2 : 3
As mass of aluminum is given as 26.98 g. So, moles of aluminum (molar mass = 26.98 g/mol) is as follows.
[tex]Moles = \frac{mass}{molar mass}\\= \frac{26.98 g}{26.98 g/mol}\\= 1 mol[/tex]
So, when 1 mole of Al reacted then 1.5 moles of hydrogen is produced as per the given mole ratio.
Therefore, mass of hydrogen formed is calculated as follows.
[tex]mass = moles \times molar mass\\= 1.5 mol \times 2.02 g/mol\\= 3.03 g[/tex]
Thus, we can conclude that the mass of hydrogen formed when 26.98 g of aluminum reacts with excess hydrochloric acid according to the given balanced equation is 3.03 g.
What is the
of a 750 milliliters solution containing 54.0 grams of KBr?
Answer:
0.605 M
Explanation:
What is the molarity of a 750 milliliters solution containing 54.0 grams of KBr?
Step 1: Given data
Mass of KBr (solute): 54.0 gVolume of solution: 750 mL (0.750 L)Step 2: Calculate the moles corresponding to 54.0 g of KBr
The molar mass of KBr is 119.00 g/mol.
54.0 g × 1 mol/119.00 g = 0.454 mol
Step 3: Calculate the molarity of the solution
Molarity is equal to the moles of solute divided by the liters of solution.
M = 0.454 mol / 0.750 L = 0.605 M
Express as ordinary numbers.
3 x 10^0 =
Answer:
the answer is 3
Explanation:
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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
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.
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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An aqueous sucrose (C12H22O11) solution must be created for an experiment. If 100.00 mL of 0.200 M solution is needed, what amount of sucrose (in grams) must be weighed out
Answer:
6.85 g
Explanation:
Step 1: Given data
Molar concentration of the solution: 0.200 M (0.200 mol/L)Volume of the solution: 100.00 mL (0.10000 L)Step 2: Calculate the moles of sucrose (solute) required
Molarity is equal to the moles of solute divided by the liters of solution.
M = moles of solute / liters of solution
moles of solute = M × liters of solution
moles of solute = 0.200 mol/L × 0.10000 L = 0.0200 mol
Step 3: Calculate the mass corresponding to 0.0200 moles of sucrose
The molar mass of sucrose is 342.3 g/mol.
0.0200 mol × 342.3 g/mol = 6.85 g
The amount of sucrose (in grams) must be weighed out for the given reaction is 6.846g.
How we calculate mass from moles?Mass of any substance will be calculated by using the moles as:
n = W/M, where
W = required mass
M = molar mass
Given that, molarity of sucrose = 0.2 M
Volume of solution = 100mL = 0.1 L
Relation between moles and molarity is represented as:
M = n/V
On putting values on the above equation we get,
n = (0.2)(0.1) = 0.02 moles
We know that molar mass of sucrose (C₁₂H₂₂O₁₁) = 342.3 g/mole
Now we calculate the required mass by putting values on the first equation as:
W = (0.02)(342.3) = 6.846g
Hence, the required mass of sucrose is 6.846g.
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What causes heat energy when you rub two objects against each other? (2 points)
Group of answer choices
The air around the objects
The flow of heat from one object to the other
The friction between the two objects
The pull of gravity on the two objects