Calculate the molality of a solution containing 15.0 g of ethylene glycol (C2H6O2) dissolved in 145 g of water.
Answer:
Molarity=moles of solute/ L of solution
Molality = moles of solute/ kg of solvent
Solute= what is being dissolved
Solvent= what is doing the dissolving
Solution= both together
Explanation:
Example's:
#1. For number one you use the Molarity formula. M= moles of solute/ L of solution.
To find moles of Mg(NO3)2 you divide 95g by its molar mass which is 148.33g so 95/148.33=.6405 moles of Mg(NO3)2. Then plug in what you have. .38M= .6405 moles Mg(NO3)2 / X. Then solve for X using algebra. .6405/.38= 1.686 L of solution. (Volume).
Final Answer: 1.686 L
#2. For number 2 you use the Molality formula. m= moles of solute/ kg of solvent.
First you have to find moles of glucose by taking 267g and dividing it by its molar mass which is 180.56g. 267g/180.56g= 1.532 moles of glucose. Then you have to change L to kg. The easiest way to do this is to look at the density and see that for every 1 ml there is 1 gram. So to take Liters to ml you multiply 1.59 by 1000 and get 1590 ml. So that means you have 1590 grams. then you divide 1590grams by 1000 to get 1.59 Kg of slovent. Then plug in your information into the formula. molality= 1.532 moles of glucose / 1.59 Kg of solvent= .964 molality.
Final answer: .964 mol/Kg
#3. m= moles of solute / Kg of solvent. 0.445 mol solute / 2.07 Kg solvent= .215 Molality
Final Answer: .215 mol/Kg
#4. m= moles of solute / Kg of solvent. take 13.5g and divide it by ethylene glycols molar mass which is 62.068 g. 13.5g / 62.068g= .218 mol. Then you take 135g of water and divide it by 1000 to get Kg. 135/1000=.135 Kg. Then plug in your information. m= .218mol/.135 Kg= 1.615 molality
Final Answer: 1.615 mol/Kg.
For a theoretical yield of 23 g and actual
yield of 13 g, calculate the percent yield for a
chemical reaction.
1. 63.6364
2. 76.4706
3. 71.4286
4. 57.1429
5. 56.5217
6. 40
7. 70
8. 60
9. 52.6316
10. 41.6667
Answer in units of %.
Answer:
5. 56.5217
Explanation:
Calculate percent yield by (actual yield / theoretical yield) times 100
(13/23) x 100 = 56.52173913
The energy of flowing electrons
A. A. LightLightB. B. ChemicalChemicalC. C. ElectricalElectricalD. D. TransformationTransformationE. E. MechanicalMechanical
Answer:
C. ElectricalElectrical
Explanation:
( it might be wrong pls dont report me just let me kno y its wrong )
Which of the following is an exothermic reaction?
a solid to a liquid
a gas change to a liquid
a liquid to a gas
a solid to a gas
Answer:
liquid to gas
Explanation:
when boiling water when evaporating heat is given out
I a doing an exam in science pls help.
What type of energy comes from the motion of tiny particles of matter?
Answer:
heat
Explanation:
Answer:
Thermal Energy
Explanation:
DUE IN 1 MINUTE HELP I'M DESPERATE
34 g of O2 are reacted with excess Cs, causing a production of 199 g of Cs2O. What is the percent yield of this
reaction?
2 Cs + O2 ---> Cs2O
Answer:
33.23 %
Explanation:
4 Cs + O₂ → 2Cs₂OFirst we convert 34 g of O₂ into moles, using its molar mass:
34 g O₂ ÷ 32 g/mol = 1.0625 mol O₂Then we convert O₂ moles into Cs₂O moles, using the stoichiometric coefficients of the balanced reaction:
1.0625 mol O₂ * [tex]\frac{2molCs_2O}{1molO_2}[/tex] = 2.125 mol Cs₂ONow we convert 2.125 moles of Cs₂O into grams, using its molar mass:
2.125 mol Cs₂O * 281.81 g/mol = 598.85 g Cs₂O598.85 g is the theoretical yield. Finally we proceed to calculate the percent yield:
199 / 598.85 * 100% = 33.23 %Pls someone help me with this question pls
Answer:
So confusing but I'll try
How many grams are in 3.5 moles of H2O?
Answer:
Hi
Explanation:
We assume you are converting between moles H2O and gram. You can view more details on each measurement unit: molecular weight of H2O or grams This compound is also known as Water or Dihydrogen Monoxide. The SI base unit for amount of substance is the mole. 1 mole is equal to 1 moles H2O, or 18.01528 grams.
1 mole is equal to 6.023 × 10 ²³ molecules. 63 grams are in 3.5 moles of H2O.
What do you mean by mole ?The term mole is defined as the amount of substance of a system which contains as many elementary entities.
One mole of any substance is equal to 6.023 × 10²³ units of that substance such as atoms, molecules, or ions. The number 6.023 × 10²³ is called as Avogadro's number or Avogadro's constant.
The mole concept can be used to convert between mass and number of particles.
We expect you are converting between moles H2O and gram. The molecular weight of H2O or gram's This compound is also known as Water or Dihydrogen Monoxide. The SI base unit for amount of substance is the mole. 1 mole is equal to 1 moles H2O, or 18.01528 grams.
Thus, 63 grams are in 3.5 moles of H2O.
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9.16 liters of CO2 weighs how many grams?
Your answer
Answer:
18.0g of CO₂ are present in 9.16L
Explanation:
To solve this question we must use:
PV = nRT
In order to find the moles of the gas and with its molar mass (44.01g/mol for CO₂) we can find the mass of the gas
Assuming STP conditions:
P = 1atm at STP
V = 9.16L
n are the moles of CO₂
R = 0.082atmL/molK
T = 273.15K
Replacing:
PV / RT = n
1atm*9.16L / 0.082atmL/molK*273.15K = n
0.409 moles = Moles of CO₂
The mass is:
0.409 moles CO₂ * (44.01g / mol) =
18.0g of CO₂ are present in 9.16L
15. Kinetic and potential energy both relate to
a. friction
a. heat
b. light
d. motion
Answer:
All forms of energy are either potential or kinetic energy. Potential refers to stored energy while kinetic is energy in motion.
Explanation:
hope help you pls thanks...
D is correct option
Why do you think there are different stars in each nighttime section of the artifact?
Answer:
The sky looks different in each nighttime section of the artifact because the artifact sections represent different seasons. ... Different constellations are visible on different nights throughout the year because of the earth's orbit. The Earth orbits around the sun. A full orbit is 365 days or one year.
Explanation:
how do you think a device could change the sound that we hear? Make sure you use vocabulary such as frequency, energy and amplitude
Answer:
good luck tho
Explanation:
how to calculate relative abundance of copper isotopes
Answer: Atomic mass (Cu) = (x)(63.0 amu) + (1 – x)(65.0 amu) = 63.5 amu 63.0x + 65 – 65.0x = 63.5 –2x = –1.5 x = 0.75 The percent abundance of each isotope is 75.0 % (Cu-63) and 25.0 % (Cu-65).
Explanation: As you know, the average atomic mass of an element is determined by taking the weighted average of the atomic masses of its naturally occurring isotopes.
Simply put, an element's naturally occurring isotopes will contribute to the average atomic mass of the element proportionally to their abundance.
Please help meeee, I will brainliest. and
Put it into your own words, if u use from internet.
Answer:
energy is used to break bonds in reactants and energy is released when new bonds form in products.The law of conservation of energy states that matter cannot be created or destroyed. Whether a chemical reaction absorbs or releases energy there is no overall change in the amount of energy during the reaction.
Explanation:
Sorry if im wrong
T/F___ At the eutectic composition, an alloy can solidify at a constant temperature.___ For effective dispersion strengthening, the dispersed phase should be needle-like, as opposed to round___ Intermetallic compounds are usually hard and brittle.___ For effective dispersion strengthening, the dispersed phase should be continuous.___ Stoichiometric intermetallic compounds exist overa range of compositions.___ Faster solidification results in smaller interlamellar spacing
Answer:
TRUEFALSETRUEFALSEFALSETRUEExplanation:
At the eutectic composition, an alloy can solidify at a constant temperature : TRUE . this is because at eutectic composition the type of reaction that takes place there is invariant reaction in its thermal equilibrium For effective dispersion strengthening, the dispersed phase should be needle-like, as opposed to round : FALSE. because the rounded shape will not cause a crack. Intermetallic compounds are usually hard and brittle : TRUE. because Intermetallic compounds prevents dislocation movements and this makes them brittle and hardFor the effective dispersion and strengthening, the dispersed phase should be continuous : FALSE. this is because the dispersed precipitate must be small and not continuous Stoichiometric intermetallic compounds exist over a range of compositions : FALSEFaster solidification results in smaller interlamellar spacing : TRUEHELPP PLZ FAST WILL GIVE BRAINLIEST
Benzene, a nonpolar, colorless solute, is most commonly found in oil and is a major component in gasoline.
In which of these two solvents will benzene most likely dissolve?
Solvent
Characteristics
A
Carbon tetrachloride
• Colorless liquid, noncombustible
• Nonpolar
Ethanol
• Flammable, colorless liquid
• Polar
Methanol
• Distinctive odor; volatile, colorless liquid
• Polar
Cyclohexane
• Strong odor; flammable; colorless liquid
• Nonpolar
OA
OB
ОС
OD
What is the ratio by atoms of elements present in technetium (VII) peroxide? (peroxide
is a polyatomic ion)
1:7
2:8
4:9
3:1
Answer: 1:7
Explanation: 2 Tc^+7 + 7 O2^-2 -> Tc2 (O2)7
Also 2 Tc to 14 O
A balloon at 30.0 C has a volume of 222 ml. if the temperature is increased to 62.1 C and the pressure remains constant, what will the new volume be, in mL?
The concept Charles's law is used here to determine the new volume. At the condition of constant pressure the new volume of the balloon is 459.54 mL.
What is Charles's law?At constant pressure, the volume of a given mass of gas is directly proportional to the temperature on Kelvin scale. Mathematically, the law can be expressed as follows:
V = constant × Temperature
V / T = Constant
V = Volume
T = Temperature
The Charles's law also explained that at -273°C, the volume of all the gases will become zero. This temperature is defined as the absolute zero.
For two different gases with volumes V₁ and V₂ and temperatures T₁ and T₂ is represented as:
V₁ / T₁ = V₂ / T₂
V₂ = V₁T₂ / T₁
222 × 62.1 / 30.0 = 459.54 mL
Thus the new volume of balloon is 459.54 mL.
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In fall, leaves may change from green to yellow or red. Explain in your own words what is happening inside the leaf with regard to plant pigments.
Answer:
The pigment that causes leaves to be green is chlorophyll. ... As chlorophyll goes away, other pigments start to show their colors. This is why leaves turn yellow or red in fall. In fall, plants break down and reabsorb chlorophyll, letting the colors of other pigments show through.
The formula for chromium (vi)bromate
Answer: The formula of chromium fluoride is CFr2.
Big assignment please help. Will do anything
Two gas particles collide together in a sealed container. What can be said about the kinetic energy of the two gas particles?
a)During the collision, each gas particle transfersall of its kinetic energy to the other particle.
b)The total kinetic energy of both gas particles will remain the same, but they can transfer any amount to each other.
c)The new kinetic energy of each gas particle is the sum of the kinetic energy that each particle is traveling with.
d)The kinetic energy of each gas particle remains the same as kinetic energy cannot be transferred between particles with zero volume.
Explanation:
c)The new kinetic energy of each gas particle is the sum of the kinetic energy that each particle is traveling with.
pls help me with this question thank you
For many years chloroform (CHCl3) was used as an inhalation anesthetic in spite of the fact that it is also a toxic substance that may cause severe liver, kidney, and heart damage. Calculate the percent composition by mass of this compound to four significant figures.
Answer:
SEE EXPLANATION
Explanation:
We must first obtain the molar mass of CHCl3 as follows;
CHCl3 = ( 12.01 * 1 )+ (1.008 * 1 ) + ( 35.45 * 3 ) => 119.37 g/mol
Then we obtain the percentage by mass of each element
For Carbon = ( atomic mass C / molar mass CHCl3 ) * 100
C = (12.01 / 119.37 ) * 100
C = ( 0.1006 * 100 )
C = 10.06 %
For Hydrogen :
H = ( atomic mass H / molar mass CHCl3 ) * 100
H = ( 1.008 / 119.37 ) * 100
H = 0.008444 * 100
H = 0.8444 %
For Chlorine :
Cl ( molar mass Cl3 / molar mass CHCl3 ):
Cl = ( 3 * 35.5 / 119.37 ) * 100
Cl = ( 106.5 / 119.37 ) * 100
Cl = 0.8921 * 100
Cl = 89.92%
Which statement is TRUE according to the kinetic molecular theory? Which statement is TRUE according to the kinetic molecular theory? A single particle does not move in a straight line. The average kinetic energy of a particle is proportional to the temperature in Kelvin. The size of the particle is large compared to the volume. The collisions of particles with one another is not completely elastic.
Answer:
The average kinetic energy of a particle is proportional to the temperature in Kelvin.
Explanation:
The kinetic molecular theory states that particles of matter are in constant motion and collide frequently with each other as well as with the walls of the container.
The collisions between particles are completely elastic. The kinetic energy of the particles of a body depends on the temperature of the body since temperature is defined as a measure of the average kinetic energy of the particles of a body.
Therefore, the average kinetic energy of a particle is proportional to the temperature in Kelvin.
Four postulates make up the kinetic-molecular theory of gases: A gas is made up of molecules moving randomly all the time. Gas molecules exclusively interact with one another through collisions; they do not apply any other forces. Every gas molecule collision is fully elastic, and all kinetic energy is conserved. Here the correct option is B.
According to the kinetic molecular theory, collisions between gas particles occur in perfect elastic motion and are always in motion. Boyle's and Charles's laws can both be explained by the kinetic molecular theory. Only absolute temperature directly affects a group of gas particles' average kinetic energy.
The collisions between particles are completely elastic. The kinetic energy of the particles of a body depends on the temperature of the body since temperature is defined as a measure of the average kinetic energy of the particles of a body.
Thus the correct option is B.
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What is the volume of 0.200 moles of O2 gas at STP?
Answer:
4.48 L O2
Explanation:
At STP, a mole of any gas contains 22.4 liters. Therefore, we simply have to multiply the amount of moles by 22.4
0.2mol O2 ( 22.4 L) = 4.48 L O2
Dominant traits are more common in a population then recessive traits
false
true
Answer:
No Just because a trait is dominant does not mean that it is present in the population
Explanation:
You prepare a standard by weighing 10.751 mg of compound X into a 100 mL volumetric flask and making to volume. You further dilute this solution 5 mL to 25 mL. This standard gives an area of 4,374. Your sample is prepared by adding 5 mL of sample solution into a 50 mL flask and making to volume. This gives an area count of 2,582. Calculate the concentration of compound X in the sample - prior to dilution.
Answer:
0.12693 mg/L
Explanation:
First we calculate the concentration of compound X in the standard prior to dilution:
10.751 mg / 100 mL = 0.10751 mg/mLThen we calculate the concentration of compound X in the standard after dilution:
0.10751 mg/mL * 5 mL / 25 mL = 0.021502 mg/LNow we calculate the concentration of compound X in the sample, using the known concentration of standard and the given areas:
2582 * 0.021502 mg/L ÷ 4374 = 0.012693 mg/LFinally we calculate the concentration of X in the sample prior to dilution:
0.012693 mg/L * 50 mL / 5 mL = 0.12693 mg/LWhy do scientists think that liquid water might have once existed on Mars?
Answer: The discovery of three buried lakes. Scientists think that a long time ago there were lakes and rivers, etc on Mars. Now of course, you can't see any visible water sources on the surface.
Answer:
Almost all water on Mars today exists as ice, though it also exists in small quantities as vapor in the atmosphere.[5] What was thought to be low-volume liquid brines in shallow Martian soil, also called recurrent slope lineae may be grains of flowing sand and dust slipping downhill to make dark streaks.The only place where water ice is visible at the surface is at the north polar ice cap. Abundant water ice is also present beneath the permanent carbon dioxide ice cap at the Martian south pole and in the shallow subsurface at more temperate conditions. More than 5 million km3 of ice have been detected at or near the surface of Mars, enough to cover the whole planet to a depth of 35 meters. Even more ice is likely to be locked away in the deep subsurface.
Some liquid water may occur transiently on the Martian surface today, but limited to traces of dissolved moisture from the atmosphere and thin films, which are challenging environments for known life. No large standing bodies of liquid water exist on the planet's surface, because the atmospheric pressure there averages just 600 pascals , a figure slightly below the vapor pressure of water at its melting point; under average Martian conditions, pure water on the Martian surface would freeze or, if heated to above the melting point, would sublime to vapor. Before about 3.8 billion years ago, Mars may have had a denser atmosphere and higher surface temperatures, allowing vast amounts of liquid water on the surface, possibly including a large ocean that may have covered one-third of the planet.Water has also apparently flowed across the surface for short periods at various intervals more recently in Mars' history. Aeolis Palus in Gale Crater, explored by the Curiosity rover, is the geological remains of an ancient freshwater lake that could have been a hospitable environment for microbial life.Many lines of evidence indicate that water ice is abundant on Mars and it has played a significant role in the planet's geologic history.The present-day inventory of water on Mars can be estimated from spacecraft images, remote sensing techniques (spectroscopic measurements, radar, etc.), and surface investigations from landers and rovers.Geologic evidence of past water includes enormous outflow channels carved by floods, ancient river valley networks, deltas and lakebeds,and the detection of rocks and minerals on the surface that could only have formed in liquid water. Numerous geomorphic features suggest the presence of ground ice (permafrost)and the movement of ice in glaciers, both in the recent past and present. Gullies and slope lineae along cliffs and crater walls suggest that flowing water continues to shape the surface of Mars, although to a far lesser degree than in the ancient past.Although the surface of Mars was periodically wet and could have been hospitable to microbial life billions of years ago, the current environment at the surface is dry and subfreezing, probably presenting an insurmountable obstacle for living organisms. In addition, Mars lacks a thick atmosphere, ozone layer, and magnetic field, allowing solar and cosmic radiation to strike the surface unimpeded. The damaging effects of ionizing radiation on cellular structure is another one of the prime limiting factors on the survival of life on the surface. Therefore, the best potential locations for discovering life on Mars may be in subsurface environments. Large amounts of underground ice have been found on Mars; the volume of water detected is equivalent to the volume of water in Lake Superior. In 2018, scientists reported the discovery of a subglacial lake on Mars, 1.5 km (0.93 mi) below the southern polar ice cap, with a horizontal extent of about 20 km (12 mi), the first known stable body of liquid water on the planet.Understanding the extent and situation of water on Mars is vital to assess the planet’s potential for harboring life and for providing usable resources for future human exploration. For this reason, "Follow the Water" was the science theme of NASA's Mars Exploration Program (MEP) in the first decade of the 21st century. NASA and ESA missions including 2001 Mars Odyssey, Mars Express, Mars Exploration Rovers (MERs), Mars Reconnaissance Orbiter (MRO), and Mars Phoenix lander have provided information about water's abundance and distribution on Mars.Mars Odyssey, Mars Express, MRO, and Mars Science Lander Curiosity rover are still operating, and discoveries continue to be made.