Answer: To be separated using GC, analytes must be volatile.
An air peak is commonly used to determine the dead time when using a TCD detector.
An FID is insensitive to non-combustible gases such as water and carbon dioxide.
A column temperature equal to or slightly above the average boiling point of the sample components results in a reasonable elution time.
Explanation:
The gas chromatography works on the principle of separation of gaseous substances based on the differences of vapor pressure. The thermal conductivity detector works on the principle of detection of effluents from the has chamber and the air peak gives indication of the retention time of the effluents. Flame ionization detector can be used for the detection of organic compounds but insensitive for the detection of halogens, non-combustible substances like carbon dioxide and water. The temperature of the column is kept higher than the average boiling point of the substance so as to attain separation of substances by the differences in the elution time.
A sample of a gas at 25°C has a volume of 150 mL when its pressure is 0.947 atm. What will the temperature of the gas be at a pressure of 0.987 atm and changes to 144mL?
*please help*
Answer:
25°C
Explanation:
Combined Gas Law (P₁V₁)/T₁ = (P₂V₂)/T₂
(0.947 atm)(150 mL)/25°C = (0.987 atm)(144mL)/T₂
5.682 = 142.128/T₂
T₂ = 142.128/5.682
T₂ = 25.0137272756°C = 25°C
What is the pH of this solution?
Answer:
pH = 11.216.
Explanation:
Hello there!
In this case, according to the ionization of ammonia in aqueous solution:
[tex]NH_3+H_2O\rightleftharpoons NH_4^++OH^-[/tex]
We can set up its equilibrium expression in terms of x as the reaction extent equal to the concentration of each product at equilibrium:
[tex]Kb=\frac{[NH_4^+][OH^-]}{[NH_3]} \\\\1.80x10^{-5}=\frac{x*x}{0.150-x}[/tex]
However, since Kb<<<1 we can neglect the x on bottom and easily compute it via:
[tex]1.80x10^{-5}=\frac{x*x}{0.150}\\\\x=\sqrt{1.80x10^{-5}*0.150}=1.643x10^{-3}M[/tex]
Which is also:
[tex][OH^-]=1.643x10^{-3}M[/tex]
Thereafter we can compute the pOH first:
[tex]pOH=-log(1.643x10^{-3}M)\\\\pOH=2.784[/tex]
Finally, the pH turns out:
[tex]pH=14-2.784\\\\pH=11.216[/tex]
Regards!
A chlorine concentration of 0.500 ppm is desired for water purification. What
mass of chlorine must be added to 2500 L of water to achieve this level?
Answer:
1.25 grams of chlorine.
Explanation:
Hello there!
In this case, since it is possible to define the parts per million of chlorine as the milligrams of chlorine per liters of water, in order to obtain the mass of chlorine in 2500 L, we proceed as follows:
[tex]ppm=\frac{mg}{L}\\\\mg=ppm*L[/tex]
In such a way, we plug in the given 0.500 ppm and 2500 L to obtain (in grams):
[tex]mg=0.500mg/L*2500L\\\\g=1250mg*\frac{1g}{1000mg}\\\\ g=1.25g[/tex]
Best regards!
Balance the following equations.
Al4C3 + H2O → Al(OH)3 + CH4
NH3 + O2 → NO + H2O
Answer:
Al4C3 +12 H2O → 4Al(OH)3 + 3CH4
4NH3 + 5O2 → 4NO + 6H2O
Which type of front is most likely moving through this area?
A. cold front
B. warm front
C. occluded front
D. stationary front
Answer:
Cold front
Explanation:
Do Newton's Laws still apply in space?
Answer:
Yes, they work in space. I forgot an example, will edit the post when I found it
Hope this helps!
What process is represented by the letter on the diagram?
A: ____________________________________________
B: ____________________________________________
C: ____________________________________________
D: ____________________________________________
E: ____________________________________________
Explanation:
I don't really understand the question
What is the concentration of a strong base solution (of an alkali metal) that has a pH of 11.39?
Answer:
[tex][OH^-]=2.455x10^{-3}M[/tex]
Explanation:
Hello there!
In this case, since a strong base produce OH ions in solution, it possible to first compute the pOH as shown below:
[tex]pH+pOH=14\\\\pOH=14-pH\\\\pOH=14-11.39\\\\pOH=2.61[/tex]
Thus, via the definition of the pOH we can compute the concentration of the strong base as follows:
[tex]pOH=-log([OH^-])[/tex]
Thus, solving for the concentration we obtain:
[tex][OH^-]=10^{-pOH}=10^{-2.61}[/tex]
[tex][OH^-]=2.455x10^{-3}M[/tex]
Best regards!
metal and one atom of a group
The following Lewis representation depicts a reaction between one atom of a group
nonmetal
eg
X.
+
x*
+
In this representation, each
atom loses
electron(s) and each
atom gains
electron(s)
Teg
The bonds that form in the product would be
Explanation:
X = Group 1 metal
Y = Group 7 Non metal
The dots basically signifies the group.
Metal loses electrons and non metal gains electron. The valency of X is 1 and that of Y is 7.
X atom loses one electron and Y atom gains one electron.
The bond that forms between a metal and a non metal is an ionic bond.
Explain why you think it is important to know the three different types of rocks.
Answer:
because they contains clues about what the earth was like in the past. different rocks from under only certain conditions and even the dullest gray lump of rock.
The element with the symbol Na
Select one
Cell
Metalloid
Non metal
Metal
Answer:
metal
Explanation:
it's a soft silvery metal
What is the total number of oxygen atoms on the left-hand side of this chemical equation?
2 Caz(PO4),(s)+48i0,(s) +12C(s) - 4 Casio2(3)+P4($)+12CO(g)
Answer:
Is the answer eight atoms
Somebody help me asap please giving brainliest
Answer:
fire > rocks > air
What is the meaning of ground state energy?
hope it helps you ❣❣
Mark me as brainliest
An experiment requires 66.6 g of ethyl alcohol (density = 0.790 g/mL). What is the volume?
Answer:
Volume = 84.30 mLExplanation:
Mass = 66.6 gram
Density = 0.790 g/mL
Volume = Mass ÷ Density
Volume = 66.6 ÷ 0.790
Volume = 84.30 mL
Sound waves vibrate your eardrum, which moves bones in your middle
ear. The soundwaves then pass through a fluid in your inner ear, and on to
tiny hairs that send signals to the brain.
A. True
B. False
Answer: A. True
Explanation:
A gas is at 39.2c and 4.50L. What is the temperature (oC) when the gas is expanded to 10L?
Answer:
420.7 degrees C
Explanation:
Use the formula V1/T1 = V2/T2 (Charles' Law) to find T2. Make sure to convert your temperatures to Kelvin by adding 273 to the Celsius temperature.
V1 = 4.50 L
V2 = 10 L
T1 = 39.2 C = 312.2 K
Solve V1/T1 = V2/T2 for T2 and you get T2 = V2T1/V1
T2 = (10 L)(312.2 K) / (4.50 L) = 693.8 K
You can subtract 273 to get the temperature back to Celsius.
T2 = 693.8 - 273 = 420.7 degrees C
An earthquake creates a type of wave that shakes the ground. If a large earthquake occurs in Greece, how can the waves be felt across the sea in Italy?
A.
Waves can be transformed into strong winds that travel across the sea.
B.
Waves do not travel through water, but they can crash the sea into land far away.
C.
Waves can cause a series of earthquakes around the world.
D.
Waves can travel through different media including solid land and water.
How many MOLECULES are in 5.0 grams of sodium chloride? (Use "molecules" as your unit...Enter as 9.9 x 10^99 molecules)
Answer:
[tex]\boxed {\boxed {\sf 5.2 *10^{22} \ molecules \ NaCl}}[/tex]
Explanation:
1. Convert grams to moles
First, convert grams to moles using the molar mass. This can be found on the Periodic Table.
Na: 22.9897693 g/molCl: 35.45 g/molSodium (Na) has an oxidation state of +1 and chlorine (Cl) has an oxidation state of -1, so they combine in a 1:1 ratio for a formula of NaCl. We can simply add their moles masses.
NaCl: 22.9897693 g/mol + 35.45 g/mol = 58.4397693 g/molUse this as a ratio.
[tex]\frac {58.4397693 \ g \ NaCl}{ 1 \ mol \ NaCl}[/tex]
Multiply by the given number of grams.
[tex]5.0 \ g \ NaCl *\frac {58.4397693 \ g \ NaCl}{ 1 \ mol \ NaCl}[/tex]
Flip the fraction so the grams of sodium chloride cancel.
[tex]5.0 \ g \ NaCl *\frac {1 \ mol \ NaCl}{ 58.4397693 \ g \ NaCl}[/tex]
[tex]5.0 *\frac {1 \ mol \ NaCl}{ 58.4397693 }=\frac {5.0 \ mol \ NaCl} { 58.4397693 } = 0.0855581749 \ mol \ NaCl[/tex]
2. Convert moles to molecules
We must use Avogadro's Number. This tells us the amount of particles (molecules, atoms, etc.) in 1 mole of a substance. In this case, it is molecules of sodium chloride.
[tex]\frac{6.022*10^{23} \ molecules \ NaCl} {1 \ mol \ NaCl}[/tex]
Multiply by the number of moles we calculated.
[tex]0.0855581749 \ mol \ NaCl*\frac{6.022*10^{23} \ molecules \ NaCl} {1 \ mol \ NaCl}[/tex]
The moles of sodium chloride cancel.
[tex]0.0855581749 *\frac{6.022*10^{23} \ molecules \ NaCl}{1}=5.15231329*10^{22} \ molecules \ NaCl[/tex]
The original measurement of grams has 2 (2 and 0) significant figures, so our answer must have the same. For the number we calculated, that is the hundredth place. The 5 in the hundredth place tells us to round the 1 to a 2.
[tex]5.2 *10^{22} \ molecules \ NaCl[/tex]
Which action is not an example of work?
A. pushing a box across the floor
B. picking up a box off the floor
C. holding a tray in the Cafeteria line
D. raising a barbell over your head
C. picking a tray in the cafeteria line
Determine the number of shared and unshared electrons in the structure. shared (bonding) electrons: unshared (lone, nonbonding) electrons: Determine the number of shared and unshared pairs of electrons in the structure. shared (bonding) pairs of electrons: unshared (lone, nonbonding) pairs of electro
Answer:
Shared (bonding) electrons : 8
Unshared (lone, non-bonding) electrons : 16
Explanation:
The Lewis dot stricture of the molecule attached to this answer shows us all the valence electrons present in the molecule.
Altogether, we have a total number of 24 valence electrons in SO3.
There are eight electrons shared between atoms of elements, these are the bonding electrons.
There are sixteen electrons that are not shared between atoms of elements, These are the lone or non-bonding electrons.
Hence, there are four shared pairs of electrons and eight pairs of unshared electrons.
When a substance is a solid it has
A. Potential energy
B. Kinetic energy
C. Gravitational energy
D. Chemical energy
Answer:
potential energy
Explanation:
9. Which of the following is needed as a reactant for cellular
respiration?
A. Carbon dioxide
B. Oxygen
C. Water
D. Chlorophyll
oxygen is needed as a reactant for cellular respiration
What is cellular respiration ?
Cellular respiration can be defined as the process which occurs in every cells mainly mitochondria of plants and animals, it involve in the break down of sugars in the presence of oxygen and releases energy in the form of ATP.
The waste product of this process are carbon dioxide and water during exhalation process done by lungs, breathing and cellular respiration are related to each other.
At every step of cellular respiration energy is used in the form of ATP and carry out the normal function. It can aerobic and anaerobic respiration on the basis of use of oxygen.
For more details regarding cellular respiration, visit
brainly.com/question/14251313
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I need help with this pls help
Answer: true
Explanation:
aluminium containers are used to store and transport nitric acid(HNO3) but not NAOH why?
Answer:
(i) Concentrated HNO3 can be stored and transported in aluminium containers as it reacts with aluminium to form a thin protective oxide layer on the aluminium surface. This oxide layer renders aluminium passive. (ii) Sodium hydroxide and aluminium react to form sodium tetrahydroxoaluminate(III) and hydrogen gas.
Question 7 (1 point)
A sample of a gas has a pressure of 0.895 bar when the volume is 318 L. What is the
pressure of the gas when the volume is 125 L?
Answer:
2.28bar
Explanation: Boyle's law P1V1=P2V2 manipulate formula in favor of V2 the new formula should beP1V1/V2
0.895*318/125=2.2768 but to same sigfig it is 2.28
ASAP!!
Identify the limiting reactant when 6 moles of CaCl2 is combined with 6 moles of Al2O3.
Reaction: 3CaCI2 + Al2O3 -> 3CaO + 2AlCI3
Answer:
just downloud smart
Explanation:
thank me later
Which element's properties form the basis for all life?
Answer:
carbon
Explanation:
The properties of carbon forms the basis for all life. Explanation: The atoms of carbon are found in the molecules of all living species.
A gas occupies 5.0 cubic meters at a temperature of 600. K. If the temperature is lowered to 300. K at constant pressure, the new volume occupied by the gas will be:
Answer:
[tex]V_2=2.5m^3[/tex]
Explanation:
Hello!
In this case, according to the Charles' law as a directly proportional relationship between volume and temperature:
[tex]\frac{V_2}{T_2}=\frac{V_1}{T_1}[/tex]
Thus, in order to compute the final volume, V2, we obtain the following expression:
[tex]V_2=\frac{V_1T_2}{T_1}\\\\V_2=\frac{5m^3*300K}{600K}\\\\V_2=2.5m^3[/tex]
Best regards!
Suppose you are titrating an acid solution with a base solution of known concentration. To calculate the concentration of the acid solution, use three steps.
1. Use the____of base____the endpoint and the known concentration of the base solution to find the_____of base used.
2. Use the_____to find the moles of acid from the moles of base.
3. Divide the moles of acid by the volume of_____the titration to find the concentration of acid.
Answer:
To calculate the concentration of the acid solution, use three steps.
1. Use the volume of base used at the endpoint and the known concentration of the base solution to find the moles of base used.
2. Use the stoichiometry to find the moles of acid from the moles of base.
3. Divide the moles of acid by the volume of acid used in the titration to find the concentration of acid.
Explanation:
Titration is the process used in volumetric analysis to determine the amount of a substance present in a given sample.
In any titration, a solution of known concentration known as the standard solution is used to react with a solution of of unknown concentration. The reacting volumes of the solutions are then used to calculate the unknown concentration of the second solution.
In acid-base neutralization reactions, an equivalence point/endpoint of the neutralization titration is obtained and is the point at which the moles of H+ is equal to the moles of OH- . An indicator is used to indicate the equivalence point during a titration by a color change observed in the indicator.
In order to calculate the concentration of an acid, we need to know accurately, use three steps:
1. Use the volume of base used at the endpoint and the known concentration of the base solution to find the moles of base used.
2. Use the stoichiometry of the reaction to find the moles of acid from the moles of base.
3. Divide the moles of acid by the volume of acid used in the titration to find the concentration of acid.
In order to calculate the concentration of a base, use three steps:
1. Use the volume of acid used at the endpoint and the known concentration of the acid solution to find the moles of acids used.
2. Use the stoichiometry of the reaction to find the moles of base from the moles of acid.
3. Divide the moles of base by the volume of base used in the titration to find the concentration of base.