Answer:
Freezing T° of solution is -142.4°C
Explanation:
This excersise is about colligative properties, in this case freezing point depression,
ΔT = Kf . m . i
Where ΔT = Freezing T° of solvent - Freezing T° of solution
Kf = Cryoscopic constant
m = mol/kg (molality)
i = Number of ions dissolved.
Water is not ionic, so i = 1
Let's find out m.
We determine mass of water, by density
498ml . 1 g/mL = 498 g
We convert the mass of water to moles → 498 g . 1mol/18g = 27.6 moles
We determine mass of solvent by density
2500 mL . 0.789 g/mL = 1972.5 g
Notice, we had to convert L to mL to cancel units.
1 cm³ = 1 mL
We convert the mass from g to kg → 1972.5 g . 1kg /1000g = 1.97kg
We determine m = mol/kg → 27.6mol / 1.97kg = 13.9 m
Kf for ethanol is: 1.99 °C/m
Freezing T° for ethanol is: -114.6°C
We replace at formula: - 114.6°C - Freezing T° solution = 1.99 °C/m . 13.9 m . 1
- 114.6°C - Freezing T° solution = 27.8 °C
- Freezing T° solution = 27.8°C + 114.6°C
Freezing T° Solution = - 142.4 °C
very urgent
1. Describe an experiment to show the chemical effect of electric current.
2. State three conditions necessary for combustion
3. Describe all that you observe when a piece of iron is placed in copper sulphate solution for a
few minutes.
Explanation:
STEP 1- Take two iron nails.
STEP 2- Clean it with sand paper.
STEP 3- Wrap copper wire around both the nails. And connect the other end to the battery terminal.
STEP 4- Take water in beaker and little amount of salt in it or a few drpos of sulphuric acid in it.
STEP 5- Immerse the nails in the solution.
STEP 6- Observe the nails carefully. You can see bubbles of gases coming out from water near nails.
When, electeric current is passed through water gases like hydrogen and oxygen are evolved.
2.Three things are required in proper combination before ignition and combustion can take place---Heat, Oxygen and Fuel. There must be Fuel to burn. There must be Air to supply oxygen. There must be Heat (ignition temperature) to start and continue the combustion process.
When iron is placed in Copper sulphate solution, the iron is coated with a brown coloured substance "copper" and CuSo4 solution changes from blue to light green. This is due to iron displaces copper as it is more reactive than copper.
How are plant and animal cells similar? How are they different? To answer these questions, make a list of the different organelles in each cell. Explain how each organelle is vital to the life and function of a plant or animal.
Answer:
A plant cell contains a large, singular vacuole that is used for storage and maintaining the shape of the cell. In contrast, animal cells have many, smaller vacuoles. Plant cells have a cell wall, as well as a cell membrane. In plants, the cell wall surrounds the cell membrane.
Which of the following may be a reason why climbing up objects would help the ivy survive?
what waves are utilized to sterilize medical equipment?
a. Gamma
b. X-ray
c. Ultraviolet
d. Radio
Answer:
B-Gamma
Explanation:
What is the acceleration due to gravity at Earth's surface?
Answer:
9.8 m/s2
Explanation:
That is to say, the acceleration of gravity on the surface of the earth at sea level is 9.8 m/s2.
Describe the arrangement and motion of the particles in liquid stearic acid.
Answer:
Its density is exactly the same as that of pure stearic acid. Its boiling point is the same as that of pure stearic acid. Its melting point is different from pure stearic acid.
which element has a smaller atomic radius than strontium (Sr)?
it is tecnically magnesium,
Answer:
barium is the answer
How many liters are there in 28g of B?
Look at the image below:
Pain Reyne
Ben Francia
Les Trans
01 Juan Bautista
Pents
SAN
PEAS FAULT
NORTH AMERICAN PLATE
CIRC PLATE
Carina
What type of plate boundary is shown here?
O convergent
divergent
transform
Answer:
Transform
see image below:
How many atoms of Mg are present in 97.22 grams of Mg?
Answer:
2.439 x 10E24 atoms
Explanation:
from
N=n x NA where
N- number of atoms
n-number of moles and NA is the avogadro's number
Anyone know how to do this?
Answer:I can’t see the question
Explanation:
If an element is very reactive, is it more likely to be found in elemental state or in a compound?
Answer:
Compound state
Explanation:
Because reactive elements mostly react immediately with other elements
What is the difference between an empirical formula and a molecular formula?
Answer:
The empirical formula simply states the ratios of the elements that make up the molecule, while molecular formulas specify the amounts of each element exactly, not just giving the ratio. Let's take ethane (C2H6) as an example.
If I react 4.2mol N2 with H2, how many moles of NH3 would I produce?
Answer:
first balance the reaction
n2 + 3h2 --> 2NH3
then you have your ratios
so for every mole of N2 you get 2 NH3
so 8.4mol is your answer
Explanation:
Bill is experimenting with two simple machines. How will he know which
machine is more efficient?
O It will use less force to do the same amount of work.
O It will use more force to do the same amount of work.
O It will be lighter and stronger than the other simple machine.
It will not be possible to tell which simple machine is more efficient.
If 3.68 grams of zinc were allowed to react with excess hydrochloric acid to produce zinc chloride and hydrogen gas, how much zinc chloride should be produced?
Suppose that 7.12 grams of zinc chloride is actually recovered, what is the per cent yield?
Answer:
Here... Since there is excess HCl, you know the Zinc will be the limiting reagent. I was able to create the reaction equation based on the info you gave: Z + 2HCl ----> ZCl2 +2H. Now, in order to find the theoretical yield of ZCl, you need to convert Zinc from grams to moles. Do this by dividing by its molar mass (65.38), thus: 3.68 (g) / 65.38 (g/mol) = 0.056286... moles.
Now, using the balanced equation we made earlier, we see that 1 mole of Zinc creates 1 mole of ZCl2. Thus our ratio is 1:1. This makes the next step easy. Since it is 1:1, we multiply the number of moles we have of Zinc (0.056286...) by the number of moles it will create of ZCl (1). (0.056286)(1) = 0.056286 moles ZCl. Now convert this to grams by multiplying by its molar mass (136.28) and you get 7.67 grams. This is your theoretical yield. The percent yield is found by dividing the actual amount obtained (7.12 g.) by the theoretical yield (7.67 g.) then multiply that by 100%. When this is done, your Percent Yield is about 92.8%
how did the periodic table get its name?
a. the periodic table got its name from the way the elements are arranged in periods called groups.
b. the periodic table got its name from the way the elements are arranged in rows which are called periods.
c. the periodic table got its name from the way the elements are arranged in rows which are called periodic groups.
d. the periodic table got its name from the way the elements are arranged in rows which are called groups.
Answer:
no te engiendo mi panahellow
Answer:
b
Explanation:
b. the periodic table got its name from the way the elements are arranged in rows which are called periods.
Look at the image below:
Palet Reyes
Preiste
Las Trances
San Juan Bautista
Panades
NORTH AMERICAN PLATE
und
SACRO PLATE
Carne Plan
ANDREAS PAUL
What type of plate boundary is shown here?
convergent
divergent
O transform
Answer:
Thats also transform boundary
Calculate the number of molecules in 64.5 grams of Nitrogen monoxide, NO
N=9.933
Explanation:
no of mole = m÷mr
then ,no of molecules=n×la
____Na3PO4+____CaCI2 --->____NaCI+ ____Ca(PO4)2
Answer:
3CaCi2 + 2Na3PO4 → Ca3(PO4)2 + 6NaCi
Explanation:
should we learn chemical kinetic derivation
Answer:
Yes
Explanation:
It is important to learn about in science
Answer : Yes
Explanation:
One reason for the importance of kinetics is that it provides evidence for the mechanisms of chemical processes. Besides being of intrinsic scientific interest, knowledge of reaction mechanisms is of practical use in deciding what is the most effective way of causing a reaction to occur.
The process of photosynthesis converts carbon atoms from carbon dioxide into....
OA. hydrogen
OB.oxygen
OC.sugars
OD.salts
Answer:
B. Oxygen
Explanation:
Answer:
C.
Explanation:
The process of photosynthesis converts those things into the sugar glucose, which it uses to sustain itself. A biproduct of this process is oxygen, but the carbon is used to make sugar. Hope this helps and brainliest is always appreciated!
Which layer of the ocean is the least dense?
Question 4 options:
they are all the same
middle layer
closest to the ocean floor
closest to the surface
Answer:
the deep ocean
Explanation:
goog le
The layer which is closest to the surface is least dense.
What are the layers of ocean?The ocean can be divided into three main layers:
The surface layer (also known as the epipelagic zone), which extends from the surface to about 200 meters deep and is the warmest and lightest layer.
The mesopelagic zone (or twilight zone), which extends from 200 to 1000 meters deep and is characterized by limited light and declining temperatures.
The bathypelagic zone (or midnight zone), which extends from 1000 to 4000 meters deep and is the coldest, darkest, and most pressure-filled layer.
Below the bathypelagic zone lies the abyssopelagic zone, which extends from 4000 to the ocean floor and is characterized by near-constant darkness and extremely cold temperatures.
Learn more about ocean layers, here:
https://brainly.com/question/12676666
#SPJ6
What happens to potential energy as kinetic energy increases during a roller coaster ride?
Answer:
On a roller coaster, energy changes from potential to kinetic energy and back again many times over the course of a ride. Kinetic energy is energy that an object has as a result of its motion. Potential energy is the energy an object has as a result of its position
Explanation:
How many atoms of aluminum (Al) are in 6.98 mol of aluminum?
Answer:
[tex]\boxed {\boxed {\sf 4.20 *10^{24} \ atoms \ Al }}[/tex]
Explanation:
To convert from moles to atoms, we must us Avogadro's number: 6.022*10²³. This tells us the number of particles (atoms, molecules, etc.) in 1 mole of a substance. In this case, it is atoms of aluminum.
We can use the number as a fraction.
[tex]\frac{6.022*10^{23} atoms \ Al}{1 \ mol \ Al}[/tex]
Multiply by the given number of moles: 6.98
[tex]6.98 \ mol \ Al *\frac{6.022*10^{23} atoms \ Al}{1 \ mol \ Al}[/tex]
The moles of aluminum will cancel.
[tex]6.98 *\frac{6.022*10^{23} atoms \ Al}{1 }[/tex]
The denominator of 1 can be ignored.
[tex]6.98 * {6.022*10^{23} atoms \ Al}[/tex]
Multiply.
[tex]4.203356*10^{24} \ atoms \ Al[/tex]
The original measurement of moles has 3 significant figures, so our answer must have the same.
For the number we calculated, that is the hundredth place. The 3 in the thousandth place tells us to leave the 0.
[tex]4.20 *10^{24} \ atoms \ Al[/tex]
There are about 4.20*10²⁴ atoms of aluminum in 6.98 moles.
Which statement is best illustrated in the diagram above regarding how the Sun's energy affects the Earth's surface from June through September in the Northern Hemisphere? The season changes from autumn to winter, daylight hours decrease, and infrared radiation is the weakest during the June solstice. B The season changes from winter to spring, daylight hours increase, and infrared radiation is the weakest during the September equinox. C The season changes from summer to autumn, daylight hours decrease, and infrared radiation is the strongest during the June solstice. The season changes from spring to summer, daylight hours increase, and infrared radiation is the strongest during the September equinox.
Answer:
I'm sorry but there is no diagram above.
Consider the data [X] [Y] [Z] initial rate M M M M · s −1 Exp 1 0.30 0.20 0.35 0.210 Exp 2 0.60 0.10 0.70 0.420 Exp 3 0.60 0.20 0.70 0.420 Exp 4 0.60 0.40 0.35 0.105 What is a correct rate law for the reaction?
Answer:
Rate = k [X]⁻¹ [Z]²
Explanation:
[X] [Y] [Z] initial rate M M M M · s −1
Exp 1 0.30 0.20 0.35 0.210
Exp 2 0.60 0.10 0.70 0.420
Exp 3 0.60 0.20 0.70 0.420
Exp 4 0.60 0.40 0.35 0.105
In Experiment 2 and 3 where the concentrations of Y and Z were constant, doubling the concentration of Y had no effect on the rate of the reaction. This means, that the rate of the reaction is zero order with respect to Y.
In experiment 3 and 4, dividing the concentration of Z by 2, causes the rate of the reaction to decrease by 4. This means the rate of the reaction is second order with respect to Z.
In experiment 1 and 4, doubling the concentration of X, causes the rate of the reaction to decrease by half. This means that X has an order of -1 with respect to the rate of the reaction.
The rate expression is given as;
Rate = k [X]⁻¹[Y]⁰[Z]²
Rate = k [X]⁻¹ [Z]²
PLS HELP ME THIS IS DUE TODAY BRO ILL BRAINLIST U JUST DO THE ONES U KNOW WAJDHWNDIGB!
Answer: Helium: atomic number 2. EC 2
Neon: atomic number 10. EC 2,8
hydrogen: atomic number 1. EC 1
magnesium: atomic number 12. EC 2,8,2
chlorine: atomic number 17. EC 2,8,7
Aluminum: atomic number 13. EC 2,8,3
Explanation: hope this helped
Im gonna ride it do it just how you like it and after that let's do it?
what is the answer of this.
Answer:
the hell?
Explanation:
.........m.......................
i need ur help guys
Answer:
Uses of Sodium chloride:
1.it is used as table salt in our diets
2. it is used as a food preservative
3. It is used as an industrial source of sodium and chlorine
Uses of Sodium hydroxide:
1. It is in the laboratory as an alkali in the neutralization of acids
2. It is used in the manufacture of soap
3. It is used in the refining of petroleum
Uses of Sodium carbonate:
1. It is used in the manufacture of detergents and glass
2. It is used to soften hard water
3. it is used to standardize acids in the laboratory
Uses of Sodium sulphate
1. It is used in the manufacture of detergents and glass
2. It is used as a purgative
3. It is used to treat wood-pulp for paper making.
Uses of Potassium nitrate
1. It is used in making gunpowder
2. It is used as rocket propellant
3. It is used in making fertilizer
Uses of Potassium chlorate
1. It is used as an oxidizer
2. It is used in making explosives
3. it is used as a disinfectant
Uses of Potassium permanganate (vii)
1. It is used as an oxidizing agent
2. It is used as a disinfectant
3. It is used as an analytical reagent
Uses of Potassium chloride
1. It is used for the manufacture of fertilizer
2. It is used as an alternative salt to sodium chloride
3. It is used in medicine to treat low blood pressure
2. Potassium nitrate and potassium chloride are used in the manufacture of fertilizers.
Potassium nitrate is used in fertilizers because it provides two important plant nutrients, nitrogen and potassium to plants.
Potassium chloride (potash) is used in fertilizers because it efficiently deliver the important plant nutrient, potassium, to plants.
Explanation:
Uses of Sodium chloride:
1. it is used as table salt in our diets
2. it is used as a food preservative
3. It is used as an industrial source of sodium and chlorine
Uses of Sodium hydroxide:
1. It is in the laboratory as an alkali in the neutralization of acids
2. It is used in the manufacture of soap
3. It is used in the refining of petroleum
Uses of Sodium carbonate:
1. It is used in the manufacture of detergents and glass
2. It is used to soften hard water
3. it is used to standardize acids in the laboratory
Uses of Sodium sulphate
1. It is used in the manufacture of detergents and glass
2. It is used as a purgative
3. It is used to treat wood-pulp for paper making.
Uses of Potassium nitrate
1. It is used in making gunpowder
2. It is used as rocket propellant
3. It is used in making fertilizer
Uses of Potassium chlorate
1. It is used as an oxidizer
2. It is used in making explosives
3. it is used as a disinfectant
Uses of Potassium permanganate (vii)
1. It is used as an oxidizing agent
2. It is used as a disinfectant
3. It is used as an analytical reagent
Uses of Potassium chloride
1. It is used for the manufacture of fertilizer
2. It is used as an alternative salt to sodium chloride
3. It is used in medicine to treat low blood pressure
2. Potassium nitrate and potassium chloride are used in the manufacture of fertilizers.
Potassium nitrate is used in fertilizers because it provides two important plant nutrients, nitrogen and potassium to plants.
Potassium chloride (potash) is used in fertilizers because it efficiently deliver the important plant nutrient, potassium, to plants.
