Solution :
We know that :
[tex]$\Delta T_f = k_f.m$[/tex] and [tex]$m=\frac{w_2}{m_2 \times w_1}$[/tex]
Then, [tex]$\Delta T_f = k_f.\frac{w_2}{m_2.w_1}$[/tex] ..................(1)
Where,
[tex]w_1[/tex] = amount of solvent (in kg)
[tex]w_2[/tex] = amount of solute (in kg)
[tex]m_2[/tex] = molar mass of solute (g/mole)
[tex]m[/tex] = molality of solution (mole/kg)
Given :
[tex]\Delta T_f[/tex] = [tex]3.14\ ^\circ C[/tex], [tex]k_f= 5.12\ ^\circ C/m[/tex]
[tex]=5.12 \ ^\circ C/mole/kg[/tex]
[tex]=5.12 \ ^\circ C \ kg/mole[/tex]
[tex]w_1[/tex] = 0.250 kg, [tex]w_2[/tex] = 24.3 g
Then putting this values in the equation is (1),
[tex]$3.14 = \frac{5.12 \times 24.3}{m_2 \times 0.250}$[/tex]
[tex]$m_2 = \frac{5.12 \times 24.3}{3.14 \times 0.250}$[/tex]
[tex]m_2= 158.49[/tex] g/mole
So, the molar mass of the unknown compound is 158.49 g/mole.
I NEED HELP ASAP !!!!
Answer:
5)A &D 6)B
Explanation:
Mass of Fe is 55.845 u
Mass of Cl is 35.453 u
And their sum is 91.298 u
Which type of energy uses the photoelectric effect?
Biomass
Solar
Geothermal
Wind
Answer:
My lovely people the answer is SOLAR
Explanation:
i just know
The type of energy that uses the photoelectric effect is solar energy. Therefore, the correct option is option B.
When light strikes a material surface, the photoelectric effect takes place, which results in the emission of electrons. Albert Einstein made this intriguing discovery in 1905, and it was essential in the development of quantum physics and our comprehension of the nature of light. The fundamental principle underlying the photoelectric effect is that light is made up of small energy packets known as photons. A photon's energy can be transferred to an electron in a solid or atom when it interacts with those structures. The type of energy that uses the photoelectric effect is solar energy.
Therefore, the correct option is option B.
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describe the components of a molecule whose atoms are joined by covalent bonds.
Answer:
nonmetal
Explanation:
In a covalent bond, the atoms bond by sharing electrons. Covalent bonds usually occur between nonmetals. For example, in water (H2O) each hydrogen (H) and oxygen (O) share a pair of electrons to make a molecule of two hydrogen atoms single bonded to a single oxygen atom.
A candle is placed between a concave mirror and its focal point.
Which two of the following best describe the image?
O A. Enlarged
B. Virtual
C. Reduced
D. Real
Virtual and enlarged..............
What grade are you in btw ?
What can a scientist use to observe very small things?
1. A good pair of glasses
2. Tools and technology
3. The five senses
4. Sense of touch
Answer:
2
Explanation:
depends on how small but you wouldn't be able to see with good glasses your senses or your touch
Answer:
Tools and Technology ( Microscopes etc)
Explanation:
Glasses are not good enough to see on the molecular and cellular level.
The five senses aren't reliable and can vary between people.
Touch is one of the 5 senses, and touching chemicals isn't good.
Name three sources of atmospheric carbon dioxide.
Answer:
Natural sources include decomposition, ocean release and respiration. Human sources come from activities like cement production, deforestation as well as the burning of fossil fuels like coal, oil and natural gas.
Which element represents magnetic properties?
Answer:Demagnetizing a magnet is also possible. Only a few substances are ferromagnetic; the most common ones are iron, cobalt and nickel and their alloys. The rare-earth metals neodymium and samarium are less common examples.
Explanation;
need help with question please ..
-20 points
Answer:
B oklolol
[tex][tex]\purple{\rule{45pt}{7pt}}\purple{\rule{45pt}{999999pt}}[tex][/tex]
6. For which movement of earth materials is gravity not the main force?
a. snow tumbling in an avalanche
b. moisture evaporating from an ocean
c. boulders carried by a glacier
d. sediments flowing in a river
Answer:
B
Explanation:
Moisture evaporating is going against the pull of gravity
What is the original source of all energy for animals? (1 point)
A. the sun
B.sugars
C.other animals
D.plants
Sugars. The food we eat is then broken down into ATP.
Answer:
The SunI
Explanation:
What is the pressure of a 1.0 L flask containing 0.12 g of He at 25°C? (R= 0.0821 L atm/mol K)
Answer:
The pressure of the flask is 0.73 atm.
Explanation:
To solve this question, we should use the ideal gas law: PV=nRT, where P represents the pressure (in atm in this case), V represents the volume (in L), n represents the number of moles of gas, R is the ideal gas constant, and T represents the temperature (in K).
Before we can plug our values into the equation, we must convert so that our units cancel out. First, we should convert our temperature from degrees Celsius to degrees K.
25°C + 273.15 = 298.15K
Next, we should convert the 0.12 g He to moles using the molar mass of He.
0.12 g He * (1 mole He/4.003 g He) = 0.029978 mol He
Now, we can plug in the values into the equation and solve for the pressure.
PV = nRT
P = (nRT)/V
P = (0.029978 mol He * 0.0821 L*atm/mol*K * 298.15 K)/(1.0 L)
P = 0.73 atm
Therefore, the correct answer is 0.73 atm.
Hope this helps!
Which of the following is not part of an amino acid?
A. ammonium group
B. carboxylate group
C. ether group
D. unique "R" group
Answer:
C
Explanation:
Ether group does not exist in amino acids
Ammonium group is on one side
the carboxylate group is opposite to the ammonium group
the R group defines what amino acid it is.
How/ why does weather "happen," on Earth?
aused by the weight of the huge numbers of air molecules that make up the atmosphere. ... When air pressure is low, air flows together and then upward where it converges, rising, cooling, and forming clouds.
Answer:
Explanation:
The weather events happening in an area are controlled by changes in air pressure. Air pressure is caused by the weight of the huge numbers of air molecules that make up the atmosphere. ... When air pressure is low, air flows together and then upward where it converges, rising, cooling, and forming clouds.
dubnium chloride chemical formula
Answer:
Db
Dubnium/Symbol
Explanation:
please mark my answer in brainlist plz
Answer:
DbCl5
Explanation
Dubnium has 2 electron in 7s orbital and 3 electron in 6d orbital. Because Dubnium is synthetically produced with atomic number of 105, it is highly radioactive and quickly decay. Like other transition, it can have different oxidation state and it is assumed that dubnium have +3,+4,+5 oxidation state number(that most likely involves electron from 6d orbital). Hence chloride ions with -1 oxidation number would react to form Dubnium Chloride as DbCl3, DbCl4, and DbCl5. Now it is highly unlikely these compounds can really be formed. However if you read nature chemistry article https://www.nature.com/articles/nchem.2610, there is mention that DbCl5, DbBr5, and DbOCl3 may be expected to form.
11) What volume will 0.75 mol of Oxygen gas (O2) occupy at 298 K and a pressure of 52.7 kPa?
Answer:
Volume = 35.3L
Explanation:
Use Ideal Gas Law (PV=nRT) and isolate for V (volume) by dividing both sides by P (pressure). You will then get the eqaution listed below and you can solve by using the method I used below.
V = nRT/P
V = (0.75kPa)(8.314)(298K)/(52.7kPa)
V = 1858.179/52.7
V = 35.3L
Determine the frequency of light with a wavelength of 2.672 x 10^-7cm
Answer:
Determine the frequency of light with a wavelength of 2.775⋅10−7 cm. Answer in units of Hz?❤
How many hydrogen atoms are in 5CH3COOH?
Answer: This formula indicates that a molecule of acetic acid (Figure 2.21) contains two carbon atoms, four hydrogen atoms, and two oxygen atoms.
Explanation:
How are all atoms of silver alike, but different from atoms of other elements?
A. All atoms of silver have the same mass.
B. All atoms of silver have the same atomic number,
C. All atoms of silver have the same number of neutrons.
D. All atoms of silver have the same number of subatomic particles.
B. All atoms of silver have the same atomic number but different numbers of neutrons in the nucleus.
OOO OOO
Water's strong hydrogen bonds result in which physical properties? Check all that apply.
high boiling point
low boiling point
high specific heat
low specific heat
density of ice being less than that of liquid water
density of ice being greater than that of liquid water
calculate the mass of 1 molecule of water and 100 molecules of glucose
Explanation:
Mass of one atom of water = Mass of 1 mole / Avogadro's number
Mass of one atom of water = 18g/mol / 6.022×10²³molecules
Mass of one atom of water = 2.989 × 10^-23 g
Mass of glucose = 180(one molecule)
Mass of 100 molecules of glucose = 180×100 =18000
How many grams of O2 are reacted when 3.5
mols of P203 are formed?
major classification of crude product
pls mark as brainlist
Explanation:
Crude is classified, based on density, as light, medium, heavy, or extra heavy. It can also be classified, based on sulfur content, into a sour and sweet category.
Hydrogen gas reacts with oxygen gas to form water. What is the excess reactant in this recation(Refer to the picture below to answer).
A. Water
B. Hydrogen gas
C. Oxygen gas
D. Water and oxygen gas
Answer: C. Oxygen Gas
Explanation: When Hydrogen Gas and Oxygen Gas combine together it forms water correct. When you have an excess amount of another it stays neutral because it has no other molecule to react with.
Which of the following best describes the arrangement of particles in a gas?
O The particles are spread apart and can move freely.
O The particles are packed closely together and can move freely.
O The particles are packed closely together and cannot move freely
O The particles are spread apart and cannot move freely.
Answer: The particles are spread apart and can move freely.
A photon is BEST described as _?
A. A subatomic particle of light
B. A negatively charged subatomic particle
C. A particle larger than an atom
D. A particle inside an atom
C= ( F - 32) / 1.8
86 F = ?
Answer:
C = 30
Explanation:
C = (86 - 32)/1.8
C = (54)/1.8
C = 30
Of the following, ________ is the most volatile. Select one: C2F6 C2H6 C2I6 C2Cl6 C2Br6
Answer:
C2Br6
because bromine is a liquid volatile
According to the forces of attraction and boiling point C₂Br₆ is most volatile as its boiling point is very low.
What are forces of attraction?Forces of attraction is a force by which atoms in a molecule combine. it is basically an attractive force in nature. It can act between an ion and an atom as well.It varies for different states of matter that is solids, liquids and gases.
The forces of attraction are maximum in solids as the molecules present in solid are tightly held while it is minimum in gases as the molecules are far apart . The forces of attraction in liquids is intermediate of solids and gases.
The physical properties such as melting point, boiling point, density are all dependent on forces of attraction which exists in the substances.
Learn more about forces of attraction,here:
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Which functional group is within the compound shown below?
(Please someone help me!) (No links!)
Please ignore the blue dot, I accidentally pressed it and won't get rid of it!
Answer:
you picked the right one the net worth of force would be 10
Explanation:
how cuz you got 1 team with 6 force then aother 1 with 4 add em up u get 10
A cell phone manufacturer recalled some 50 million lithium batteries installed in cell phones because the batteries were at risk of overheating and exploding. The hazardous waste characteristic of the batteries in this example is __________.
Answer:
universal waste
hope it helps
