Write
the following separation techniques?
a. Filtration
b. Evaporation
C. Fractional distillation
d. Chromatography
Answer:
Explanation: Fractional distillation
Please answer it truthfully please
Answer:
False
Explanation:
Chemical and Physical changes happen uniquely, they cannot happen at the same time. When you crumble a piece of paper you don't change its chemical form you change its physical form. When a piece of metal rusts its chemical composition changes, leading me to believe it is false.
Good luck on the rest of your assignment/test!
what's the formula for na and f , ca and br , mg and O
Answer:
NaF, CaBr2, MgO
Explanation:
Hi! For this problem, you are going to want to look at the charges of the elements in order to write their formulas.
NaF: Na has a charge of +1 and F has a charge of -1. This means that they have a 1:1 ratio and the formula is written as such - NaF.
CaBr2: Ca has a charge of +2 and Br has a charge of -1. For this problem you want to make sure that their formal charge (the charge of the entire molecule) equals 0. This means that the negative charges need to equal the positive charges. Looking at this, you are going to need to Br ions with a charge of -1 to equal one Ca ion with a charge of +2 - CaBr2.
MgO: Mg has a charge of +2 and O has a charge of -2. This means that they have a 2:2 ratio which simplifies to a 1:1 ratio and the formula is written as such - MgO.
Hope this helps!
which is a way to express concentration of a solution? parts per billion moles molar mass force per square meter
Answer:
parts per billion
Explanation:
I took the quiz
Answer:
parts per billion
Explanation:
edge 2021
Solve for x in the following equation?
v=w/x
Answer:
x = w/v
General Formulas and Concepts:
Pre-Algebra
Equality PropertiesExplanation:
Step 1: Define
v = w/x
Step 2: Solve for x
Multiply x on both sides: xv = wDivide v on both sides: x = w/vWhich three are advantages of asexual reproduction?
A:Offspring are more likely to survive environmental changes.
B:Some offspring are more likely to survive a disease.
C:Less energy is required to reproduce.
D:The population can increase from only one parent.
E:The population can increase quickly.
Answer:
sorry if I get this wrong I think it is C
Explanation:
find the number of hydrogen atoms of an alkyl group with 2 carbon atoms if n=2
Answer:
5
Explanation:
An alkyl group is a functional group that contains only hydrogen and carbon atoms. It has the general formula: CnH2n+1.
Since n=2, plug it into the formula.
C2H2(2)+1
=
C₂H₅
Hope that helps.
Find the volume of
this object.
5 cm
5 cm
5 cm
A
15 cm3
B
125 cm3
C
30 cm3
Answer: B. [tex]125\ cm^3[/tex].
The volume of the given object = [tex]125\ cm^3[/tex]
Explanation:
Given : Dimensions of an object : 5 cm x 5 cm x 5 cm [ it is a cube with all equal sides]
Formula to find the volume of a cube = [tex](side)^3[/tex]
[tex]=5^3\ cm^3=125\ cm^3[/tex]
Hence, the volume of the given object = [tex]125\ cm^3[/tex]
Therefore , the correct option is B. [tex]125\ cm^3[/tex].
Calculate the energies of the n=2 and n=3 states of the hydrogen atom in Joules per
atom
Answer:
See Explanation
Explanation:
Positional Energy for electron as function of principle energy level (n)
=> Eₙ = -A/n²; A = 2.18x10⁻¹⁸J
Positional Energy for electron in n=2 => E₂ = -2.18x10⁻¹⁸/(2)² = -5.45x10⁻¹⁹J
Positional Energy for electron in n=3 => E₃ = -2.18x10⁻¹⁸/(3)² = -2.42x10⁻¹⁹J
ΔE(n=3→2) = -5.45x10⁻¹⁹J - (-2.42x10⁻¹⁹J) = -3.03x10⁻¹⁹J
A piece of dry ice at -76°C begins to sublimate (solid to
gas) when placed at the counter at room temperature. How
many bars are in the final phase energy (Eph)?
Answer:
D
Explanation:
4 bars
At room temperature (20 °C), milk turns sour in about 64 hours. In a refrigerator at 3 °C, milk can be stored three times as long before it sours.
(a) Estimate the activation energy of the reaction that causes the souring of milk.
(b) How long should it take milk to sour at 40 °C?
Answer: Since k2 corresponds to 64 hours, the time for the milk to sour at 40 C is 64 h / 9.38 = 6.8 hours.
Explanation:
At temperature T1, the Arrhenius Equation is:
k1 = Ae^(-Ea/RT1).
An equivalent equation can be written at T2:
k2 = Ae^(-Ea/RT2).
If these equations are divided, then A cancels:
k1/k2 = e^(-Ea/RT1)/e^(-Ea/RT2)
Taking the natural log:
ln(k1/k2) = (Ea/RT2)-(Ea/RT1);
or:
ln(k1/k2) = (Ea/R)(1/T2 - 1/T1)
We can infer from the question that the milk sours 3 times as fast at the higher temperature (let's call it T1), so we can arbitrarily call k2 = 1 and k1 = 3.
a) Substitute:
ln(3) = (Ea/R)(1/276.15 K - 1/293.15 K).
We get Ea/R = 5231.6. Multiply this by whatever value of R you choose to get Ea in your favorite energy unit. Remember the sig figs.
b) Again, let's let the lower temperature = T2, since we have defined k2 = 1:
ln(k1) = (5231.6)(1/276.15 K - 1/313.15);
ln(k1) = 2.24, so k1 = 9.38.
Since k2 corresponds to 64 hours, the time for the milk to sour at 40 C is 64 h / 9.38 = 6.8 hours.
Relate the properties of atoms, their position in the periodic table, and their number of valence electrons to their chemical reactivity.
Answer:
Explanation:
An atom is the smallest unit of an element that can take part in a chemical reaction. Atoms are made up of protons, neutrons and electrons. Atoms can exist as a monoatomic (such as in the case of Helium, Xenon and Neon) or as diatomic (such as in the case of oxygen and nitrogen). Atoms take part in a chemical reaction and there reactivity varies among themselves.
From the above, it can be deduced that atoms have protons, neutrons and electrons. The number of protons (which is positively charged) of an atom determines it's position on the periodic table because elements in the periodic table are arranged according to the number of protons (called atomic number). The electron(s) present in the outermost shell of each atom (called valence electrons) determines there chemical reactivity. What happens here is that, all atoms (except noble gases) want to achieve there duplet or octet configuration so as to become stable. This octet configuration means they want to have there outermost shell completely filled (with eight electrons or two electrons for duplet). They usually achieve this configuration by taking part in chemical reactions. Thus, when an atom has just one electron in it's outermost shell, it becomes easy to lose it to another atom by way of interacting with it in a chemical reaction. When it loses this single electron (valence electron) in it's outermost shell, it becomes stable with the inner completely filled shell (that would be the new outermost shell). Examples include Lithium, sodium and potassium. Sodium (with eleven electrons and three shells) would lose the single electron in it's outermost shell so as to have just two shells with the second shell completely filled with eight electrons. Thus, the more the valence electron to be lost to achieve the octet structure, the lesser the reactivity of the atom.
Also, an atom that has just one electron to complete it's own outermost shell and thus achieve it's octet structure is also highly reactive. This is also because it is easy for this atom to receive a single electron and become completely filled. Examples include chlorine, fluorine and iodine. Fluorine (with nine electrons and two shells) will easily accept one more electron so as to achieve it's octet structure with a completely filled outermost shell (of eight electrons). Thus, the lesser the electrons to be gained to achieve the octet configuration, the higher the chemical reactivity of such atoms. Noble gases have extremely low or no reactivity at all for this reason because it has a completely filled outermost shell (no losing or donating).
It should also be noted that metals (which are found on the left of the periodic table) exist as monoatomic while gases (which are found on the right), with the exception of noble gases, are mostly diatomic.
The reactivity of atoms of elements in the periodic table depends on their valency as well as their position in the periodic table.
The periodic table contains an arrangement of atoms in order of increasing atomic numbers. Elements in the periodic table are arranged in groups. Each group of elements have atoms that contain the same number of valence electrons.
Atoms of alkali and alkaline earth metals as well as atoms of halogens are highly reactive. This has something to do with the number of valence electrons they contain. The alkali and alkaline metals give out their electrons easily are high reactive while the halogens accept electrons easily are also highly reactive.
Alkali and alkaline earth metals have a few valence electrons so they give them out easily. Halogens have seven valence electrons hence they accept electrons easily. Reactivity of metals generally decreases from left to right in the periodic table while the reactivity of nonmetals increases from left to right. The elements of group 18 are placed in the last group because they are unreactive.
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1) How many moles are in 4.0x10^24 atoms?
Answer:
6.64 molesExplanation:
To find the number of moles in a substance given it's number of entities we use the formula
[tex]n = \frac{N}{L} \\[/tex]
where n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question we have
[tex]n = \frac{4 \times {10}^{24} }{6.02 \times {10}^{23} } \\ = 6.644518...[/tex]
We have the final answer as
6.64 molesHope this helps you
A sample of helium gas at 841 mmHg and 14.7°C is heated to 84.7°C at constant volume. Calculate its final pressure (in atm).
_________________ atm. Do NOT enter unit. Report your final answer with 3 SFs.
Answer: 1.38
Explanation:
Gay-Lussac's Law: This law states that pressure is directly proportional to the temperature of the gas at constant volume and number of moles.
[tex]P\propto T[/tex] (At constant volume and number of moles)
[tex]\frac{P_1}{T_1}=\frac{P_2}{T_2}[/tex]
where,
[tex]P_1[/tex] = initial pressure of gas = 841 mm Hg
[tex]P_2[/tex] = final pressure of gas = ?
[tex]T_1[/tex] = initial temperature of gas =[tex]14.7^0C=(14.7+273)K=287.7K[/tex]
[tex]T_2[/tex] = final temperature of gas = [tex]84.7^0C=(84.7+273)K=357.7K[/tex]
[tex]\frac{841}{287.7}=\frac{P_2}{357.7}[/tex]
[tex]P_2=1045.6mm Hg=1.38atm[/tex] ( 760 mm Hg = 1atm )
Thus the final pressure is 1.38
Can someone help me I only have 5 minutes left.
Becky places a strip of metal into a clear liquid and they react. A has given off . The liquid is most likely which kind of substance?
Answer:
The liquid is likely to be a base e.g Sodium hydroxide solution or Ammonia solution
The liquid is likely to be a Base .
Acid and baseThe terms acid and base describe chemical characteristics of many substances that we use daily. Acidic things taste sour. Basic or alkaline things taste soapy. Strong acids are corrosive and strong bases are caustic; both can cause severe skin damage that feels like a burn. However, mild acids and bases are common and relatively harmless to us.
2 H2O ⇌ 1 H3O+ + 1 OH-
Examples of bases are sodium hydroxide, calcium carbonate and potassium oxide. A base is a substance that can neutralize the acid by reacting with hydrogen ions. Most bases are minerals that react with acids to form water and salts.Basic substances react to aqueous solutions by accepting protons, giving away electrons, or releasing hydroxide ions. They neutralize acids by reacting with hydrogen ions to form salts and water. A base that dissolves in water is also known as an alkali.The scale has values ranging from zero (the most acidic) to 14 (the most basic). As you can see from the pH scale above, pure water has a pH value of 7. This value is considered neutral—neither acidic or basic.Learn more about base, refer
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which of the following could be classified as producing a physical change?
Which is larger: barium atom or a barium ion? Explain your answer in terms of atomic structure
Would a highly conductive, malleable, and lustrous solid be a metal, nonmetal, or metalloid?
Balance this equation.
_Mg +_Cl2 -->_MgCl2
Answer:
1Mg + 1Cl2 = 1MgCl2
Explanation:
Hi! When balancing an equation, you want to make sure that there are equal amounts of each element on both sides. When looking at the equation that you provided in the question, look and count how many of each element are on each side. I can see that there is 1 Mg ion on the left and 1 Mg ion on the right. There are also 2 Cl ions on the left and 2 Cl ions on the right. Because they are already equal, the coefficients in front of each compound will be 1. If the amounts were different on each side, that is when you would need to add different coefficients.
Hope this helps! Let me know if you have any other questions about this!
What statements are always true about limiting reactants?
Select one or more:
1.The limiting reactant has a lower mass than other reactants.
2.The limiting reactant dictates the amount of product.
3.The limiting reactant is always the same for a given reaction.
4.There will be an excess of other reactants at the end of the reaction.
5.The limiting reactant is completely used up in the reaction.
Answer:
5.The limiting reactant is completely used up in the reaction
Explanation:
The limiting reactant is completely used up in the reaction is the correct answer because a limiting reactant is a reactant in chemical reaction that is completely consumed or used up in the chemical reaction. Limiting reactant when it is completely used up limits the amount of products that will be formed. The reaction will be halted or will stop when the limiting reactant is totally used up.
The statement that is right as regards a limiting reactants in a reaction is 5:.The limiting reactant is completely used up in the reaction.
The limiting reagent can be regarded as a reactant during chemical reaction, which is been consumed totally at the end of the reaction without remains. The amount of product that is formed during a reaction can be limited by action of the limiting reagent this is because once this reagent is used up the reaction cannot proceed again.Therefore, option 5, is correct.
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OTHER OPTIONS THAT COMPLETE THIS QUESTION ARE:
The limiting reactant has a lower mass than other reactants.
2.The limiting reactant dictates the amount of product.
3.The limiting reactant is always the same for a given reaction.
4.There will be an excess of other reactants at the end of the reaction.
ASAP PLZ HELP I WILL MARK BRAINLIEST Based on the diagram, what can you conclude about the pole of the magnet? O It is a south pole because the field lines spread out from this end. O It is a north pole because the field lines spread out from this end, O It is a south pole because the field lines enter the magnet at this end. O It is a north pole because the field lines enter the magnet at this end.
Answer:C
Explanation:I took the test
Answer:
It is a south pole because the field lines enter the magnet at this end.
Explanation:
through which filter did water went through faster?
Answer:
The filter that water went through faster is Filter paper
Please help with this....thank you
Answer:
large cracks suddenly form
Explanation:
the tectonic plates begin to move causing cracks. I think
Which of the following statements is true about exothermic reactions?
Answer:
An Exothermic Reaction , gives off more heat, and a little energy to its surroundings.
this can helps us figure out that the answer is , C, More heat is given off into its products.
Explanation:
How many
electrons does Oravetium contain
In the organization of living things, tissues combine to form
A)Cells
B)communities
C) organisms
D)Organs
Answer:
D
Explanation:
Answer:d
Explanation:
An ideal gas sample is confined to 3.0 L and kept at 27 °C. If the temperature is raised to 77 °C and the initial pressure was 1500 mmHg, what is the final pressure?
The gas is confined in 3.0 L container ( rigid container) ⇒ the volume remains constant when the temperature is increased from from 27oC to 77oC and therefore V1=V2 .
Hope it helps you please mark as brainlistIdeal gas law is valid only for ideal gas not for vanderwaal gas. Ideal gas is a hypothetical gas. Vanderwaal gas can behave as ideal gas at low pressure and high temperature. Therefore the final pressure is 1,750 mmHg.
What is ideal gas equation?Ideal gas equation is the mathematical expression that relates pressure volume and temperature.
Mathematically the relation between Pressure, volume and temperature can be given as
PV=nRT
where,
P = pressure of gas
V= volume of gas
n =number of moles of gas
T =temperature of gas
R = Gas constant = 0.0821 L.atm/K.mol
At constant volume, the above equation can be rearranged as
P₁/T₁ = P₂/T₂
Substituting all the given values in the above equation, we get
1500 ÷300= P₂÷350
P₂ =1,750 mmHg
Therefore the final pressure is 1,750 mmHg.
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Which elements are considered metals? Non-metals? Metalloids?
The answer is in the photo.
Which defines the average inetic energy of a system's particles?
O density
O pressure
O temperature
O volume