Answer:
49.0g/mol is molar mass of X
Explanation:
551mg of X are dissolved in 100g of benzonitrile
Freezing point of solution: -13.4°C
The freezing point depression of a solution (Colligative property) follows the equation:
ΔT = Kf*m*i
Where ΔT is change in freezing point from the pure solvent (Benzonitrile: -12.8°C) to the solution (-13.4°C)
Kf is freezing point depression of benzonitrile: 5.34°C/m
m is molality of the solution (Moles X / kg of benzonitrile)
And i is Van't Hoff factor (1 for any solute in benzonitrile)
ΔT = -12.8°C - (-13.4°C) = 0.6°C
Solving for molality of the solution:
ΔT = Kf*m*i
0.6°C = 5.34°C/m*m*1
0.1124m = molality of the solution
Moles of X are:
0.1124mol/kg benzonitrile * 0.1kg benzonitrile = 0.01124 moles X
In 551mg = 0.551g:
Molar mass:
0.551g / 0.01124mol =
49.0g/mol is molar mass of X
Benzene has a heat of vaporization of 30.72 kj/mol and a normal boiling point of 80.1 oC. At what temperature does benzene boil when the external pressure is 490 torrtorr?
Answer:
THE TEMPERATURE AT THE EXTERNAL PRESSURE OF 490 TORR IS 550.72 C
Explanation:
Heat of vaporization = 30.72 kj/mol
Normal boiling point = 80.1 C
Pressure = 490 torr
So therefore, with the above variables given, the relationship between heat of vaporization, pressure and temperature is given by this equation:
ln (P2/P1) = - ^H vap/ R ( 1/ T2 - 1/T1)
H vap = 30.72 kj/mol
P1 = 760 torr ( this is so because the normal boiling point occurs at the vapor pressure equal to the atmospheric pressure which value is 760 torr)
T1 = 80.1 + 273 = 353.1 K
P2 = 490 torr
R = 8.314 J/mol K
T2 = unknown
Re-arranging the formula bu=y making T2 the subject of the equation, we have;
T2 = 1 / (1/T1) - (R / Hvap) (ln (P2/P1))
Introducing the variables into the equation, we have:
T2 = 1 / (1 / 353.1 ) - (8.341 / 30.72 * 10 ^3) ln (490 / 760)
T2 = 1/ (0.00283 - 0.27* 10^-3 ln 0.6447)
T2 = 1 / 0.00283 - 0.27*10^-3 (- 0.43897)
T2 = 1 / 0.00283 + 0.1185 * 10 ^-3
T2 = 1 / 0.1214 *10^-3
T2 = 1 / 0.001214
T2 = 823.72
T2 = 823.72 - 273 = 550.72 C
The temperature when the external pressure is 490 torr is 550.72 C
When two or more substances blend but do not chemically combine it is a _____________.
Answer:
Mixture.
Explanation:
Hello,
In this case, when blending we are continuously sliding the substances until we obtain small particles that when do not chemically but physically combine we say they are forming a mixture. Nevertheless, when they chemically combine they form a chemical compound due to the formation of bonds between them.
Regards.
Determine the number of significant figures in each of the following
a. 0.00376 ______
b. 1.00377 ______
c. 43,000 ______
d. 14.06 ______
e. 14.00 ______
f. 3200.0 ______
Answer:
A. 3 Significant Figures
B. 6 Significant Figures
C. 2 Significant Figures
D. 4 Significant Figures
E. 4 Significant Figures
F. 5 Significant Figures
Explanation:
Which of the following is an example of element? A.Water B.Chlorine C.Carbon Dioxide D.Sugar
Which structure is found in some but not all plant cells? vacuole ribosome cell wall lysosome
Answer:
lysosome
Explanation:
Lysosomes contain enzymes that break down the macromolecules and foreign invaders
Answer:
lysosome
Explanation:
name one benifit and one limitation of comparative investigations
Answer:
Limitation of comparative investigation is that when it is done on a huge population, huge amount cost is required. Explanation: Benefit of comparative investigation is that we can get descrete information about specific breed or species. It is important for the study of behaviour of many organisms.
Explanation:
A recipe for spaghetti sauce requires 2.5 cups of tomato sauce. If only metric measures are available, how many milliliters of tomato sauce are needed? (1qt = 4 cups, 1q = 946 mL)
Answer:
6.0 × 10² mL
Explanation:
Step 1: Given data
A recipe for spaghetti sauce requires 2.5 cups of tomato sauce.
Step 2: Calculate the US Quarts (qt) corresponding to 2.5 cups of tomato sauce
We will use the relationship 1 qt = 4 cups.
2.5 cups × (1 qt/4 cups) = 0.63 qt
Step 3: Calculate the milliliters (mL) corresponding to 0.63 qt of tomato sauce
We will use the relationship 1 qt = 946 mL.
0.63 qt × (946 mL / 1 qt) = 6.0 × 10² mL
test results indicated a chemical change has taken place
Arrange the compounds by boiling point. a. A pentane molecule with the condensed structure CH3CH2CH2CH2CH3. b. A neopentane molecule with the condensed structure C(CH3)4. c. A hexane molecule with the condensed structure CH3CH2CH2CH2CH2CH3.
Answer:
Hexane > pentane > neopentane
Explanation:
The boiling point of alkanes varies with chain length. The greater the length of the chain, the greater its boiling point.
Since hexane consists of a longer chain than pentene, its boiling point is definitely higher than that of pentane.
Similarly, neopentane is a branched alkane, the boiling point of a branched alkane is always lower than that of its straight chain counterparts.
Hexane has the highest boiling point due to its higher molecular weight, followed by pentane, and neopentane has the lowest boiling point due to its highly branched structure.
The boiling point is primarily influenced by two factors: molecular weight and branching. The higher the molecular weight, the stronger the van der Waals forces and, therefore, the higher the boiling point. Branching in a molecule tends to disrupt the intermolecular forces, reducing the boiling point.
Hexane has a higher molecular weight than pentane, so it would generally have a higher boiling point than pentane.
Neopentane is highly branched, with four methyl (CH3) groups attached to the central carbon. This branching significantly disrupts the intermolecular forces, reducing the boiling point compared to straight-chain molecules like pentane and hexane.
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How many constitutionally isomeric monochlorination products are possible from the following?a. 2-Methylpentane b. 3-Methylpentane c. 2,2-Dimethylbutane d. 2,3-Dimethylbutane
Answer:
a. 5
b. 4
c. 3
d. 2
Explanation:
How many constitutionally isomeric monochlorination products are possible from the following?
a. 2-Methylpentane
In 2-methylpentane, there are five possible monochlorinated substitutional products in the reaction of chlorination of 2-methylpentane in the presence of sunlight.
b. In 3-methylpentane there are four possible monochlorinated substitutional products in the reaction of chlorination of 3-methylpentane in the presence of sunlight.
c. In 2,2-Dimethylbutane there are three possible monochlorinated substitutional products in the reaction of chlorination of 2,2-Dimethylbutane in the presence of sunlight.
d. In 2,3-Dimethylbutane there are two possible monochlorinated substitutional products in the reaction of chlorination of 2,3-Dimethylbutane in the presence of sunlight.
the mass if an element is .007502 x 10^-26 g. find the Number of significant figures when the mass is converted to mg. (both masses values have same order of magnitude)
Answer:
d. 4.
Explanation:
Hello,
In this case, the required number on milligrams is:
[tex]0.007502x10^{-26}g*\frac{1000mg}{1g}=7.502x10^{-26}mg[/tex]
It means that it has four significant figures which are counted for 7, 5, 0 and 2, considering that zero as it is to the right of first nonzero digit (7).
Regards.
The solar wind is made up of ions, mostly protons, flowing out from the Sun at 400 km/s. Near Earth, each cubic kilometer of interplanetary space contains, on average, 6 x 10^15 solar-wind ions. How many moles of ions are in a cubic kilometer of near-Earth space?
Answer:
9.96x10⁻⁹ moles of ions are in a cubic kilometer
Explanation:
As the problem states, in the near-earth space there are 6x10¹⁵ ions.
Moles are an amount of substance defined as 6.022x10²³. 1 mole of ions are 6.022x10²³ ions
1 mole of substance is 6.022x10²³ particles.
As there are 6x10¹⁵ ions in a cubic kilometer, the moles are:
6x10¹⁵ ions * (1mol / 6.022x10²³ ions) =
9.96x10⁻⁹ moles of ions are in a cubic kilometerBased on the formula for calculating moles of particles, there are 9.96 * 10⁻⁹ moles of ions in a cubic kilometer of interplanetary space.
What is the moles of ions?The moles of ions is determined using the formula below:
Moles of a particle = number of particles / 6.02 * 10²³Data provided:
Number of ions = 6 * 10¹⁵ ions
Moles of ions = 6 * 10¹⁵ ions/6.02 * 10²³
moles of ions = 9.96 * 10⁻⁹ moles of ions.
Therefore, there are 9.96 * 10⁻⁹ moles of ions in a cubic kilometer of interplanetary space.
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Why do minerals with metallic bonds conduct electricity so well?
Answer and Explanation:
Because metallic bonding involves delocalized electrons. It is described as a "sea of electrons", because the electrons are not confined around the nucleus of metal atoms, but they are delocalized: thay can be located in one nucleus and then in another neighbor atom. Thus, the electrons have more freedom to move from one part of the metal to another and electricity is well conducted.
What phase(s) of matter are the elements in Main Group 8?
Answer:
Solids.
Explanation:
Group 8 on the Periodic Table consists of transition metals:
- Fe (Iron)
- Ru (Ruthenium)
- Os (Osmium)
- Hs (Hassium)
Usually, transition metals are solids.
For the masses and volumes indicated, calculate the density in grams per cubic centimeter.
a. mass = 4.53 kg; volume = 225cm^3
b. mass = 26.3 g; volume = 25.0 mL
c. mass = 1.00 lb; volume = 500. cm^3
d. mass = 352 mg; volume = 0.271 cm^3
The masses and volumes indicated, calculate the density in grams per cubic centimeter mass = 1.00 lb; volume = 500. cm^3. Thus option c is correct.
What is density?Density is defined as a material is the measure of how densely it is packed together.
It can also be defined as a measure of the density of a substance or object's mass.
The SI unit of density is kilogram per cubic meter or gram per cubic meter
Density can be expressed as
Density = mass / volume
Density = 1.00 / 500
Density = 0.002 lb / cm^3
Thus, the masses and volumes indicated, calculate the density in grams per cubic centimeter mass = 1.00 lb; volume = 500. cm^3. Thus option c is correct.
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A 515cm^3 flask contains 0.460 g of a gas at a pressure of 153 kPa and a temperature of 322K. What is the molecular mass of this gas
Answer:
Molecular mass, [tex]M=28.89\ \text{g/mol}[/tex]
Explanation:
Given that,
Mass of gas, m = 0.46 g
Volume of the container, V = 515 cm^3
Pressure, P = 153 kPa
Temperature, T = 322 K
We need to find the molecular mass of this gas. We know that,
PV =nRT
n = no of moles
[tex]n=\dfrac{PV}{RT}\\\\n=\dfrac{153\ kPa\times 0.515\ L}{8.31447\ LkPaK^{-1}{mol^{-1}}\times (322+273)\ K }\\\\n=0.01592\ \text{moles}[/tex]
No of moles = mass/molecular mass
Let molecular mass is M
[tex]M=\dfrac{m}{n}\\\\M=\dfrac{0.46}{0.01592}\\\\M=28.89\ \text{g/mol}[/tex]
So, the molecular mass of this gas is [tex]28.89\ \text{g/mol}[/tex]
The electron configuration 1s22s22p63s23p64s23d104p3 represents which element?
Explanation:
Arsenic.................
The electron configuration 1s22s22p63s23p64s23d104p3 represents Arsenic.
The electronic configuration is represented as follows;
1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p³.
Count the number of electrons to know the element. The number of electron in an electronically neutral atom is equal to the number of proton.
The number of proton is the atomic number of the element. Therefore,
2 + 2 + 6 + 2 + 6 + 2 + 10 + 3 = 33
The atomic number is 33. The element with atomic number of 33 is Arsenic. Therefore, the element is Arsenic.
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Psychoanalysis (Freud) is concerned with Question 1 options: chemical balances in the brain someone's measurable actions childhood trauma Self-actualization
Answer:
childhood trauma.
Explanation:
I took the test and the answer i got correct was Childhood trauma.
What am I calculating for when solving for 17.0 mL of ethanol, density of ethanol= 0.94 g/mL
Answer:
you are caculating for the mass/wight of ethanol
Explanation:
DxV=M
Please help me Solve this *I DONT WANT THE ANSWER* Just give me a good explanation...
Answer:
C
Explanation:
'Ordered Arrangement' basically means that it is a solid at room temperature. Room temperature is approximately 15-20C so we are looking for melting and boiling points that are above room temperature so it hasn't/can't melt or boil at room temperature and would therefore be solid. Option C is the only one where both points are temperatures above room temperature therefore option C is the only one where the substance would be in an 'ordered arrangement' at room temperature.
Hope this helped!
Which of the following elements is a metalloid? A. vanadium (V) B. radon (Rn) C. silicon (Si) D. rubidium (Rb)
Answer:
silicon
Explanation:
Causes warm air to rise in the atmosphere. is what type of heat transfer?
Answer: Convection
Explanation: Convection is the transfer of heat energy in a fluid. This type of heating is most commonly seen in the kitchen with a boiling liquid. Air in the atmosphere acts as a fluid.
A 18.00 g g milk chocolate bar is found to contain 11.00 g g of sugar.1. How many milligrams of sugar does the milk chocolate bar contain?2. What will be the amount of sugar in milligrams if the size of the milk chocolate bar is reduced from 18.00 g to 4.000 g ? Express your answer in milligrams to four significant figures.
Answer:
1. 1.100x10⁴mg
2. 2444mg
Explanation:
1. The 18.00g milk chocolate bar contain 11.00g of sugar. In miligrams:
11.00g * (1000mg / 1g) = 1.100x10⁴mg
2. If a bar of 18.00g contain 11.00g of sugar, a bar of 4.000g will contain:}
4.000g bar * (11.00g / 18.00g) = 2.444g of sugar.
In miligrams:
2.444g * (1000mg / 1g) = 2444mg
can someone please help me
hroughout the reflection, make sure you have a copy of the Student Guide and your data table. Choose the terms that complete the statements. In this lab, you determined the combination of humidity, air temperature, and air pressure that create weather patterns. is the amount of water vapor in the air compared to the amount of water vapor the air can actually hold. is a measure of how hot or cold the air is, and is the force exerted per unit area by the particles in the air. These conditions influence weather patterns.
Answer:
A. relative humidity B. air temperature C. air pressure D. atmospheric
Explanation:
just completed the assignment
Answer:
Basically reconfirming what the other guy said
Explanation:
Relative humidity
Air temperature
Air pressure
Atmostpheric
Yall have a nice day.
What are formed when particles in solar wind travel along lines of Earth's magnetic field and collide with gas atoms?
Answer: Auroras
Explanation:
Hope this helps
Answer:
Option Auroras is correct
Explanation:
I got it right.
A biochemical reaction will proceed in the direction as written if:_______a. ΔG > 0.b. ΔH > 0.c. ΔG = zero.d. ΔG < 0.e. ΔH < 0.
Answer:
ΔG < 0
Explanation:
The condition for spontaneity of a chemical reaction is that ∆G<0. Hence for any biochemical reaction to proceed as written, ∆G must have a negative value.
If ∆G >0, the reaction is not spontaneous and will not proceed as written. ∆G=0 means that the reaction has attained equilibrium.
You have developed a promising anti-cancer agent, but it has poor solubility in water. Which of the following changes should improve water solubility? ( there is two possible answers)a) adding a methyl groupb) adding a hydroxyl groupc) adding a carboxyl groupd) increasing the size of the druge) adding a benzene ring
Answer:
adding a hydroxyl group
adding a carboxyl group
Explanation:
The addition of a hydroxyl or a carboxyl group to the molecule will increase its solubility. This is because, the -OH group will form hydrogen bonds with the water molecules. The formation of such hydrogen bonds will lead to improvement in the solubility of the anti cancer agent and solve the problem of poor solubility of the anticancer agent in water.
what is the order of technological design
Explanation:
steps of the technological design process include: identify a problem, research the problem, generate possible solutions, select the best solution, create a model, test the model, refine and retest the model as needed, and communicate the final solution.
Draw a second resonance structure for the following ion (be sure to include the charges and all lone pairs)... + ..N=N=N <-------------->.. ..
Answer:
Explanation:
Resonance structure occurs in an organic compound that undergoes resonance effects. This resonance effect is sometimes called the mesomeric effect helps to increases the stability of organic compounds that have alternating single bonds and double bonds.
The second resonance structure diagram for the ion given in the question can be found in the attached diagram below.