Answer:
Pure crystals of the substance of interest are recovered using crystalization
It can be used to obtain substances that decompose on heating.
Explanation:
Crystalization is the process of converting a liquid solution to a crystalline solid. It is a common method of extracting the solid product of a reaction from solution. It can also be a separation method especially for obtaining pure crystals from a solution.
Crystalization does not require heating. Common methods of inducing crystalization include; addition of crystals of the same substance as seeds or scratching the vessel containing the solution.
The advantage of crystalization over evaporation is that it can be used to recover substance that decompose on heating. Also crystalization yields pure crystals of the substance of interest compared to evaporation in which soluble impurities may not be completely removed.
Of the following, which can be used to identify an element present in a sample?
Answer:
idk but i tryed
Explanation:
The simplest way to use the periodic table to identify an element is by looking for the element’s name or elemental symbol. The periodic table can be used to identify an element by looking for the element’s atomic number. The atomic number of an element is the number of protons found within the atoms of that element.
What is Rutherford atomic modle
Answer:
Rutherford's atomic model explained how the electrons surrounded the nucleus of protons and neutrons. His model showed how J. J. Thomson's Plum Pudding model was incorrect.
Answer:Rutherford model of an atom shows that an atom is mostly an empty space,with electrons orbiting a fixed positively charged nucleus in set.
Explanation:
DNA is an example of a:
O A. Compound
B. Element
c. Mixture
D. Atom
Answer:
The answer is option A.
Compound
Hope this helps you
Which substance is a mixture? Table salt, gasoline, aluminum, carbon dioxide?
Answer:
b.) gasoline
Explanation:
The rest mentioned are pure substances/compounds which is not a mixture.
A substance is said to be a mixture if they are not able to get dissolved completely in the solution. Gasoline is a mixture. Thus, option B is correct.
What are mixtures?Mixtures are the substances that are formed by mixing two or more compounds that have been not able to show any chemical bond and linkage. They are physical combinations rather than chemicals.
Gasoline is a homogeneous mixture that is formed by the combination of hydrocarbons and differs from other substances that are pure substances or compounds.
Table salt, aluminum, and carbon dioxide are pure substances that are formed of the same type of molecules or atoms. Table salt is made of Na and Cl atoms, aluminum is made of a single atom, and carbon dioxide of carbon and oxygen atom.
Therefore, gasoline is a mixture.
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The law of conservation of energy states that energy cannot be created or . However, energy can be from one substance to another.
Answer:
destroyed.
transferred.
Explanation:
hehe
Answer:
Your answer would be destroyed and Transferred.
Explanation:
The reason why is because energy is never created or destroyed because it is just transferred to different forms of energy. Suich as a ball at the top of a hill. It's not moving, so it has potential energy, (potential energy is energy that is stored) and let's say that some wind comes through and gives that ball a push, so now the ball is moving and is going downhill. now the ball has kinetic energy because it was transferred to a moving energy from a stored energy.
A welding torch produces a flame by burning acetylene fuel in the presence of oxygen. This flame is used to melt a metal. Which energy transformation represents this process?
chemical energy into thermal energy
kinetic energy into potential energy
kinetic energy into electromagnetic energy
potential energy into chemical energy
Answer:
chemical energy into thermal energy
Explanation:
The reaction taking place is as follows
2C₂H₂ + 5O₂ = 4CO₂ + 2H₂O + Heat
In this reaction bonds present in acetylene is broken and new bond present in water and carbon dioxide are formed . In the whole process of bond breaking and bond formation , there is net loss of energy and that energy is released as heat energy .
Thus we can say that in the whole process , chemical energy is converted into heat energy .
Answer:
A: chemical energy into thermal energy.
Explanation:
Why is making proteins important
2.70g of Zn (s) reacts with 50.0 mL of 1.00 M HCl solution to produce hydrogen gas according to the reaction. (R = 0.08206 L·atm·K-1·mol-1) Zn(s) + 2HCl (aq) = ZnCl2 (aq) + H2(g) a) calculate mole of Zn used in this reaction b) calculate mole of HCl used in this reaction c) calculate which reactant is a limiting reactant d) calculate mole of hydrogen gas formed e) calculate volume of H2 gas at STP in Liters that will be produced during the reaction
Answer:
a. 0.0413 moles Zn
b. 0.0500 moles HCl
c. HCl is the limiting reactant
d. 0.0250 moles H₂
e. V = 0.56L
Explanation:
The reaction of Zn(s) with HCl is:
Zn(s) + 2HCl (aq) → ZnCl₂ (aq) + H₂(g)
Where 1 mole of Zn reacts with 2 moles of HCl.
a) To convert mass in grams to moles of a substance you need to use molar mass (Molar mass Zn: 65.38g/mol), thus:
2.70g Zn × (1mol / 65.38g) = 0.0413moles of Zn
b. Now, when you have a solution in molarity (Moles / L), you can know the moles of a volume of solution, thus:
Moles HCl:
50.0mL = 0.0500L × (1.00mol / L) = 0.0500 moles HCl
c. The limiting reactant is founded by using the chemical reaction as follows:
For a complete reaction of 0.0500 moles HCl you need:
0.0500 moles HCl × (1 mole Zn / 2 moles HCl) = 0.0250 moles Zn
As you have 0.0413 moles of Zn, and you need just 0.0250 moles for the complete reaction, Zn is the exces reactant and HCl is the limiting reactant
d.As HCl is limiting reactant and 2 moles of HCl react with 1 mole of H₂, moles of hydrogen formed are:
0.0500 moles HCl × (1 mole H₂ / 2 moles HCl) = 0.0250 moles H₂
e. Using PV = nRT, you can find volume of gas, thus:
PV = nRT
V = nRT / P
Where P is pressure 1atm at STP, n are moles, R is gas consant 0.08206Latm/molK and T is absolute temperature 273.15K at STP.
V = 0.0250molesₓ0.082atmL/molKₓ273.15K / 1atm
V = 0.56L
What type of contamination do peroxides produce?
Answer:
The main hazard related to organic peroxides are their fire and explosion hazards. ... It is the double oxygen of the "peroxy" group that makes organic peroxides both useful and hazardous. The peroxy group is chemically unstable. It can easily decompose, giving off heat at a rate that increases as the temperature rises.
Explanation:
Consider the chemical equations shown here.
P4(s) + 302(g) - P406(S) AH1 = -1,640.1 kJ
P4010(s) - P4(s) + 5O2(g) AH2 = 2,940.1 kJ
What is the overall enthalpy of reaction for the equation shown below?
Round the answer to the nearest whole number.
P406(S) + 2O2(g) → P4010(s)
DONE
Answer:
-1,300 kJ
Explanation:
P₄ + 3 O₂ ⇒ P₄O₆ ΔH = -1,640.1 kJ (EQ 1)
P₄O₁₀ ⇒ P₄ + 5 O₂ ΔH = 2,940.1 kJ (EQ 2)
These are the equations you are given. You need to make these equations into the equation below.
P₄O₆ + 2 O₂ ⇒ P₄O₁₀ (end equation)
Look at the product side of the end equation. You need to produce P₄O₁₀. In the EQ 2, P₄O₁₀ is on the reactant side. Flip the equation. Since you flipped the equation, the enthalpy will have the opposite sign.
P₄ + 5 O₂ ⇒ P₄O₁₀ ΔH = -2,940.1 kJ
On the reactant side of the end equation, you need P₄O₆ and 2 O₂. First, rearrange the equation so that P₄O₆ is on the right side. In EQ 1, P₄O₆ is on the product side. Flip the equation. Like the last one, the sign will change.
Now, cancel out all possible values. P₄ will cancel out since there is one on each side of the equation. Since there is 5 O₂ on one side and 3 O₂ on the other, subtract the two and put the remainder on the side of the larger value.
P₄ + 5 O₂ ⇒ P₄O₁₀ ΔH = -2,940.1 kJ
P₄O₆ ⇒ P₄ + 3 O₂ ΔH = 1,640.1 kJ
P₄O₆ + 2 O₂ ⇒ P₄O₁₀
This should be the resulting equation. Now, add the two enthalpies together to find the overall enthalpy.
-2,940.1 kJ + 1,640.1 kJ = -1,300 kJ
The overall enthalpy is -1,300 kJ.
-867.7Answer:
Explanation:
-867.7
(4 marks)
A farmer distributed his cabbages as follows: A certain hospital received a quarter of the
total number of bags. A nearby school received half of the remainder. A green grocer
received a third of what the school received. What remained were six bags more than
what the green grocer received. How many bags of cabbages did the farmer have?
(3
Answer:
Explanation:
Let the farmer had n no of bags of cabbage .
given to hospital = n / 4
given to school = 1/2 x 3n /4
= 3n / 8
given to grocer = 1 / 3 x (3n / 8 )
= n / 8
No of bags distributed
= n / 4 + 3n / 8 + n / 8
= 6n / 8
Remaining bag
= n - 6n / 8
= 2n / 8
According to question
2n / 8 = 6 + n / 8
n / 8 = 6
n = 48 .
A compound ‘X’ is used for drinking, has pH =7.Its acidified solution undergoes decomposition in presence of electricity to produce gases ‘Y’ and ‘Z’ The volume of Y is double than Z. Y is highly combustible whereas Z is supporter of combustion. Identify X, Y & Z and write the chemical reactions involved.
Answer:
X = Water (H2O) ; Y = Hydrogen ; Z = Oxygen
Explanation:
2(H2O) -------> 2H2 + O2
What are two important fuels that comes out of the oil refining process?
Diesel fuel and kerosene.
Gasoline and diesel are used as fuels for motor vehicles.
Kerosene is used as jet fuel.
Naphthar is a major petrochemical feedstock.
I hope this helps..
What is the acceleration of the object’s motion? 0.5 m/s2 -0.5 m/s2 2 m/s2 -2 m/s2
Answer: -2m/s2
Explanation:
Using the following equation ; acceleration = Change in velocity / time
i.e a = v - u / t
where 'a' = acceleration
v = final velocity
u = initial velocity
t = time
Therefore; from the graph we have acceleration to be, 0 - 6m/s / 3s = -2m/s2
Examine the graph showing the half life of the radioactive isotope substance x. Based on this graph, what might be the best use of thos radioactive isotop?
Determining the age of the objects less than 50000 years old.
Long term radioactive dating such as in dating rocks
Short term radioactive imaging such as nuclear medicine.
Determining the age of objects over 1000000 years old
Answer:
Long term radioactive dating such as in dating rocks
Explanation:
If we examine the graph carefully, we will notice that the number of atoms falls to zero after about 40000 years. This is quite a long time! Many rock formations were formed thousands of years ago and their ages can only be measured by an isotope that has an equally long half life.
Hence for an isotope with such a long half-life, we can effectively measure the age of a rock formation that contains the particular isotope in question. Rocks are composed of diverse chemical isotopes which are normally used to determine the age of the rock formation. Since rocks were formed thousands of years ago, these isotopes must be capable of having a half-life of thousands of years also in order to be useful in measuring the age of rocks.
What reaction is depicted by the given equation: Au3+ + 3e− Au
A. oxidation B. reduction C. combustion D. replacement E. neutralization
Answer:
The answer is option B.
Reduction
Hope this helps you
Answer:
plato answer b
Explanation:
define noble gases ?
Answer:
The noble gases are the chemical elements in group 18 of the periodic table. They are the most stable due to having the maximum number of valence electrons their outer shell can hold. Therefore they rarely react with other elements since they are already stable
Paul and Peter are weight lifters, Paul lifts 100kg barbell over his head 10 times in 1 minutes. Peter lifts 100kg barbell over his head 10 times in 10 seconds. Who has more power? Give your reasons.
Answer:
Peter
Explanation:
Peter has more power, as he is able to lift the same amount of weight as Paul in a much shorter time.
If Paul can lift 100kg 10 times in 1 minute, and Peter can lift 100kg 10 times in 10 seconds, Peter is 6 times stronger than Paul, because 1 minute, or 60 seconds, is 6 times longer than 10 seconds.
The pressure of a 1-L nitrogen gas sample at 25 ⁰C is 0.30 atm. The pressure of a 1-L oxygen gas sample at the same temperature is 0.25 atm. The oxygen gas sample is added to the nitrogen container. Argon gas is added to the mixture until the total pressure of the 1-L container reaches 1.00 atm, and the temperature is adjusted to 25 ⁰C. According to Dalton’s Law of Partial Pressures, the contribution of each gas to the total pressure of the gas mixture is: Nitrogen _____________ Oxygen _____________ Argon _____________
Answer:
Nitrogen = 0.3 atm
Oxygen = 0.25 atm
Argon = 0.45 atm
Explanation:
According to Dalton's law of partial pressure, the total pressure in the container is equal to sum of the partial pressures of the individual gases.
Given;
Total pressure of the gases, P_total = 1 atm
Pressure of nitrogen, P_nitrogen = 0.3 atm
Pressure of oxygen, P_oxygen = 0.25 atm
Pressure of argon, P_argon = ?
[tex]P_{total} = P_{nitrogen} + P_{oxygen} + P_{argon}\\\\1 \ atm= 0.3 \ atm + 0.25 \ atm + P_{argon}\\\\1 \ atm= 0.55 \ atm + P_{argon}\\\\ P_{argon} = 1 \ atm - 0.55 \ atm\\\\ P_{argon} = 0.45 \ atm[/tex]
Therefore, the contribution of each gas to the total pressure of the gas mixture is;
Nitrogen = 0.3 atm
Oxygen = 0.25 atm
Argon = 0.45 atm
How do I write these decimal numbers in expanded form? 0.913, 0.205, 0.047, 0.480
Thanks! :)
Explanation:
To write a decimal in expanded form, write the number as a sum of its place values.
0.913 = 0.9 + 0.01 + 0.003
0.205 = 0.2 + 0.005
0.047 = 0.04 + 0.007
0.480 = 0.4 + 0.08
The protoplasm of a living cell is made up of nucleus and what ?
Answer:Carbon containg molecules
Explanation:
Protoplasm is made up of necleus and carbon containing molecules
Answer:
Protoplasm is composed of a mixture of small molecules such as ions, amino acids, monosaccharides and water, and macromolecules such as nucleic acids, proteins, lipids and polysaccharides. In eukaryotes the protoplasm surrounding the cell nucleus is known as the cytoplasm and that inside the nucleus as the neoplasm.
Explanation:
Which statement describes how the Van Allen belts are formed? O when low-energy particles from the Sun bounce off Earth’s magnetic field O when high-energy particles from the Sun bounce off Earth’s magnetic field O when low-energy particles from the Sun are trapped by Earth’s magnetic field O when high-energy particles from the Sun are trapped by Earth’s magnetic field (Earth/Space Science)
Answer:
when high-energy particles from the sun are trapped by earth's magnetic field
Explanation:
it is produced by a "depression" in the Earth's magnetic field in that area, caused by the fact that the center of the Earth's magnetic field is deviated from its geographic center by 450 km. Such an anomaly is thought by some to be a side effect of a Geomagnetic Reversal. These radiation belts originate from the Earth's intense magnetic field that is the product of their rotation. That field traps charged particles (plasma) from the Sun (solar wind), as well as charged particles that are generated by interaction of the Earth's atmosphere with cosmic radiation and high-energy solar radiation.
Answer:
D
Explanation:
its the last one
What characteristics determine how easily two substances change temperature? Check all that apply.
volume of the two substances in contact
amount of time the two substances are in contact
area in contact between the two substances
specific heat of the material that makes up the substances
Odensity of the two substances in contact
amount of time the two substances are in contact. area in contact between the two substances. specific heat of the material that makes up the substances. the density of the two substances in contact.
The characteristics determine how easily two substances change temperature is amount of time the two substances are in contact, area of contact between the two substances, specific heat of the material that makes up the substances and the density of the two substances in contact. Therefore, option B, C, D and E are correct.
When two substances have different temperatures come into contact?When two substances that have different surface temperatures come in contact, conduction happens. The substance with the higher temperature always transfers energy to the one with the lower temperature.
When two objects with different temperatures come in contact with one another, energy moves from the hotter (higher temperature) object to the cooler (lower temperature) object until both objects reach the same temperature.
The latitude of the location has an impact on the air temperature there. The location's elevation. separation from the ocean.
Thus, option B, C, D and E are correct.
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2. Se combinan 40 g de SO2 y 25 g de O2 determine el porcentaje en masa del exceso con respecto a su masa inicial. P.A. (S = 32; O = 16) SO2 + O2 SO3
Answer:
60%
Explanation:
En la reacción:
2SO₂ + O₂ → 2SO₃
Donde 2 moles de SO₂ reaccionan por mol de O₂.
El peso atómico del SO₂ es:
1S = 32g/molₓ1 = 32g/mol
2O = 16g/molₓ2 = 32g/mol
SO₂ = 32g/mol + 32g/mol = 64g/mol
Y el peso atómico de O₂ es:
2O = 16g/molₓ2 = 32g/mol
Las moles de SO₂ y O₂ son:
SO₂: 40g ₓ (1mol / 64g) = 0.625 moles
O₂: 25g ₓ (1mol / 32g) = 0.7813 moles
Para una completa reacción de SO₂ se necesitan:
0.625 moles SO₂ ₓ (1mol O₂ / 2 mol SO₂) = 0.3125 moles de O₂
Así, las moles en exceso de O₂ son:
0.7813 moles - 0.3125 moles = 0.4688 moles O₂
En gramos:
0.4688 moles O₂ ₓ (32g / mol) = 15g O₂ están en exeso.
El porcentaje en exceso es:
15g / 25g ₓ 100 =
60%For+the+reaction+H2+++I2+-+2HI+the+equilibrium+constant,+kc+is+49+at+a+fixed+temperature.+Two+mole+of+hydrogen+and+two+moles+of+iodine+are+allowed+to+reach+equilibrium+at+this+temperature.+What+is+the+concentration+of+hydrogen+iodide+at+equilibrium?
Answer : The initial concentration of HI and concentration of HI at equilibrium is, 0.27 M and 0.386 M respectively.
Solution : Given,
Initial concentration of H_2 and I_2 = 0.11 M
Concentration of H_2 and I_2 at equilibrium = 0.052 M
Let the initial concentration of HI be, C
The given equilibrium reaction is,
H_2(g)+I_2(g)\rightleftharpoons 2HI(g)
Initially 0.11 0.11 C
At equilibrium (0.11-x) (0.11-x) (C+2x)
As we are given that:
Concentration of H_2 and I_2 at equilibrium = 0.052 M = (0.11-x)
The expression of K_c will be,
K_c=\frac{[HI]^2}{[H_2][I_2]}
54.3=\frac{(C+2(0.058))^2}{(0.052)\times (0.052)}
By solving the terms, we get:
C = 0.27 M
Thus, initial concentration of HI = C = 0.27 M
Thus, the concentration of HI at equilibrium = (C+2x) = 0.27 + 2(0.058) = 0.386 M
Why do alkenes not appear in the periodic table
Answer:
Alkenes are unsaturated hydrocarbons.
Alkenes do not appear in the periodic table because the periodic table consists only of elements.
How much oxygen will contain the same number of atoms as the number of molecules in 73 g of HCI?
Answer:
64g of O2.
Explanation:
We'll begin by calculating the number of molecules in 73g if HCl.
This is illustrated below:
From Avogadro's hypothesis, we understood that 1 mole of any substance contains 6.02×10²³ molecules. This implies that 1 mole of HCl also contains 6.02×10²³ molecules
1 mole of HCl = 1 + 35.5 = 36.5g
Thus, if 36.5g of HCl contains 6.02×10²³ molecules, then 73g of HCl will contain = (73 x 6.02×10²³)/36.5 = 1.204×10²⁴ molecules.
Therefore, 73g of HCl will contains 1.204×10²⁴ molecules.
Now, we shall determine the mass of oxygen that will contain 1.204×10²⁴ molecules.
This can be obtained as follow:
1 mole of O2 = 16x2 = 32g
32g of O2 contains 6.02×10²³ molecules.
Therefore, Xg of O2 will contain 1.204×10²⁴ molecules i.e
Xg of O2 = (32 x 1.204×10²⁴)/6.02×10²³
Xg of O2 = 64g
Therefore, 64g of O2 will contain the same number of molecules (i.e 1.204×10²⁴ molecules) in 73g of HCl.
A perfume bottle is dropped in the comer of a room. The odor of the perfume can be detected on the other side of the statement best describes this observation? Particles are moving from regions of high concentration to low concentration.Particles are moving from regions of low concentration to high concentration. Particles are moving through a small opening into a smaller volume. Particles are moving through a small opening into a larger volume.
Answer:
Particles are moving from regions of high concentration to low concentration.
hope this answer correct (^^)
Answer:
A. Particles are moving from regions of high concentration to low concentration.
Explanation:
took a test
Please help, I don't under stand! Balance the following oxidation-reduction reaction and indicate which atoms have undergone oxidation and reduction. ____FeCl3 + ____H2S Imported Asset ____FeCl2 + ____S + ____HCl
Answer:
3 FeCl3 + H2S = 2 FeCl2 + S + 2 HCl
Explanation:
Fe goes form +3 to +2
S goes from -2 to 0
H and Cl are spectator ions
Fe3+ + 1e-= Fe2+
H2S = S + 2 H+ + 2e-
3 Fe3+ + H2S = 2 Fe2+ + S + 2 H+
3 FeCl3 + H2S = 2 FeCl2 + S + 2 HCl
Which of the following is an example of a behavioral trait that
is likely to increase reproductive success?
O colorful feathers
O a dance
O tail length
Answer:
The answer is option A
Colorful feathers
Hope this helps you