Answer:
1, 1, 2, 3
Explanation:
The numbers 1 and 8 both have 1 sig. fig.
The number 13 has 2 sig. figs.
The number 104 has 3 sig. figs.
1.Using the absorbance of the spinach extract and the equation of the trendline, determine the concentration of the extract solution. Report the concentration in moles/L (M).
2. Calculate the number of rams of chlorophyll-a in the 25ml, spinach solution.
3. Calculate the concentration of the chloropyhll-a soultion in spinach (mg chlorophyll-a/g spinach)
Trendline: y=1609x + .0055
Absorbance spinach extract lamda max: .329
Absorbacne spinach extract, 750 nm: .023
Corrected absorbance: .306
Mass of Spinach: .1876g Total Volume of spinach: 25mL
Answer:
Explanation:
From the given information:
We are to make use of the spinach absorbance extract which is the corrected absorbance (y) = 0.306
And also the trendline equation:
y = 1609x + 0.0055
where,
x = absorbance of the spinach extract.
∴
0.306 = 1609x + 0.0055
collecting the like terms
0.306 - 0.0055 = 1609x
0.3005 = 1609x
x = 0.3005/1609
x = 1.8676 × 10⁻⁴
x ≅ 0.0002 M
No. of grams for the chlorophyll can be computed as follows:
recall that:
molar mass of chlorophyll = 893.5 g/mol
the volume = 25ml = (25/1000) L = 0.025 L
∴
In spinach solution, the no. of grams for the chlorophyll:
= (0.0002) mol/L × (893.5 g/mol) × (0.025) L
= 0.0044675 g
≅ 0.0045 g
In the spinach, the concentration of chlorophyll = no of grams of chlorophyll/ mass of the spinach
= 4.5 mg/0.1876 g
= 23.987 mg/g
≅ 24 mg/g
From the given information:
We are to make use of the spinach absorbance extract which is the corrected absorbance (y) = 0.306ChlorophyllChlorophyll is any member of the class of the green pigments involved in the photosynthesis process.
And also the trendline equation:
y = 1609x + 0.0055
where,
x = absorbance of the spinach extract.
so 0.306 = 1609x + 0.0055
collecting the like terms
0.306 - 0.0055 = 1609x
0.3005 = 1609x
x = 0.3005/1609
x = 1.8676 × 10⁻⁴
x ≅ 0.0002 M
2. No.of grams for the chlorophyll can be computed as follows:
recall that:
molar mass of chlorophyll = 893.5 g/mol
The volume = 25ml = (25/1000) L = 0.025 L
Therefore:
In spinach solution, the no. of grams for the chlorophyll:
= (0.0002) mol/L × (893.5 g/mol) × (0.025) L
= 0.0044675 g
≅ 0.0045 g
3. In the spinach, the concentration of chlorophyll = no of grams of chlorophyll/ mass of the spinach
= 4.5 mg/0.1876 g
= 23.987 mg/g
≅ 24 mg/g
Read more about chlorophyll here:
https://brainly.com/question/3529377
How to calculate the actual volume (ml) of water removed from the burette with water
density 1 g/ml:
i. 5mL of water removed
Answer:
Explanation:
The density of pure water is 1 gram per 1 milliliter or one cubic cm. By knowing the density of water we can use it in dilution equations or to calculate the specific gravity of other solutions.
It can also help us determine what other substances are made of using the water displacement experiment. This is done by observing how much water is displaced when an object is submerged in the water. As long as you know the density of the water, the mass of the object being submerged and the volume of increase you can calculate the density of the object.
This was done by the great Archimedes in discovering what composed the kings crown.
Which equation was used by Albert Einstein to explain the photoelectric effect? [E = energy, h= planck's constan, and v = frequency]
Answer:
E = hv
Explanation:
Energy = planck constant × frequency
the Wavelength of a microwave is______than the wavelength of visible light
(Please help)
Answer:
The wavelength of a microwave is LONGER than the wavelength if visible light.
4.005 X 74 X 0.007 = 2.10049
Answer:
2.07459
Explanation:
this is the correct answer.
The doctor has ordered Claforan 1 g in 100 ml D5W to run IV piggyback for 30 minutes twice daily. The pharmacy sends Claforn 2 g in a powdered form, which when reconstituted has a concentration of 180 mg Claforan per ml. How much Claforn will you add to the bag of D5W
Answer:
0.111 g
Explanation:
1 g = 1000 mg
Doctor ordered the following concentration of Claforan:
C = 1 g/100 mL x 1000 mg/1 g = 10 mg/mL
If we add 2 g iof Claforan, we obtain:
2 g Claforn ---- 180 mg/mL Claforan
To reach a concentration equal to C (10 mg/mL), we need:
10 mg/mL Claforan x 2 g Claforn/(180 mg/mL Claforan) = 0.111 g Claforn
Therefore, we have to add 0,111 g (111 mg) of Claforn to the bag of 100 ml D5W to obtain the ordered concentration of 10 mg/mL Claforan.
calculate the molarity in a 0.550 m solution of NaCl in water. Assume that the solution density is 1.03g/mol
Answer:
M=0.549M
Explanation:
Hello there!
In this case, according to the given information, it turns out possible for us to perform this calculation by firstly assuming we have 1 kg of water as the solvent so that we have 0.550 moles of NaCl as well. Moreover, we realize we have 1000 grams of water and the correct mass of the solution can be calculated by converting 0.550 moles of NaCl to grams by using its molar mass:
[tex]m_{solute}=0.550mol*\frac{58.44 g}{1mol}= 32.14g\\\\m_{solution}=1000g+32.14g=1032.14g[/tex]
And subsequently, the volume in liters by using the density and the correct conversion factor:
[tex]V_{solution}=1032.14g*\frac{1mL}{1.03g} *\frac{1L}{1000mL} =1.002L[/tex]
Finally, the molarity will be:
[tex]M=\frac{0.550mol}{1.002L} =0.549M[/tex]
Regards!
A 2,31M solution of trans-4-methyl-2-pentene (C6H12, 85mL) is combined with 7,5mL of 3,55M elemental bromine to form an addition product. With an expectation of 100% yield, more than 25mmols of elemental bromine would be consumed during this chemical process.
a. True
b. False
Answer:
The statement is false
Explanation:
Number of moles of alkene = 2.31 × 85/1000 = 0.196 moles
Number of moles of Br2 = 3.55 × 7.5/1000 = 0.0266 moles
Given that the reaction is 1:1
1 mole of alkene reacts with 1 mole of bromine
0.196 moles of alkene should react with 0.196 moles of bromine
Hence, to achieve 100%yield, 0.196 moles of bromine and not 25mmols of elemental bromine
The gas law for an ideal gas at absolute temperature T (in kelvins), pressure P (in atmospheres), and volume V (in liters) is PV = nRT, where n is the number of moles of the gas and R = 0.0821 is the gas constant. Suppose that, at a certain instant, P = 8.0 atm and is increasing at a rate of 0.13 atm/min and V = 13 L and is decreasing at a rate of 0.17 L/min. Find the rate of change of T with respect to time (in K/min) at that instant if n = 10 mol.
Answer:
The rate of change of T with respect to time is 0.40 K/min
Explanation:
The gas law equation is:
[tex] PV = nRT [/tex]
We can find the rate of change of T with respect to time by solving the above equation for T and derivating with respect to time:
[tex] \frac{dT}{dt} = \frac{d}{dt}(\frac{PV}{nR}) [/tex]
[tex] \frac{dT}{dt} = \frac{1}{nR}(V\frac{dP}{dt} + P\frac{dV}{dt}) [/tex]
Where:
n: is the number of moles = 10 mol
R: is the gas constant = 0.0821
V: is the volume = 13 L
P: is the pressure = 8.0 atm
dP/dt: is the variation of the pressure with respect to time = 0.13 atm/min
dV/dt: is the variation of the volume with respect to time = -0.17 L/min
Hence, the rate of change of T is:
[tex] \frac{dT}{dt} = \frac{1}{10*0.0821}(13*0.13 - 8.0*0.17) = 0.40 K/min [/tex]
Therefore, the rate of change of T with respect to time is 0.40 K/min
I hope it helps you!
How many grams of O2 are needed to react with 8.15 g of C2H2?
Answer:
25.08 grams of O₂ are needed to react with 8.15 g of C₂H₂.
Explanation:
The balanced reaction is:
2 C₂H₂ + 5 O₂ → 4 CO₂ + 2 H₂O
By reaction stoichiometry, the following amounts of moles of each compound participate in the reaction:
C₂H₂: 2 molesO₂: 5 molesCO₂: 4 molesH₂O: 2 molesThe molar mass of each compound is:
C₂H₂: 26 g/moleO₂: 32 g/moleCO₂: 44 g/moleH₂O: 18 g/moleThen, by reaction stoichiometry, the following mass quantities of each compound participate in the reaction:
C₂H₂: 2 moles* 26 g/mole= 52 gO₂: 5 moles* 32 g/mole= 160 gCO₂: 4 moles* 44 g/mole= 176 gH₂O: 2 moles* 18 g/mole= 36 gThen you can apply the following rule of three: if by stoichiometry 52 grams of C₂H₂ react with 160 grams of O₂, 8.15 grams of C₂H₂ react with how much mass of O₂?
[tex]mass of O_{2} =\frac{8.15 grams of C_{2} H_{2}*160 grams of O_{2} }{52 grams of C_{2} H_{2}}[/tex]
mass of O₂= 25.08 grams
25.08 grams of O₂ are needed to react with 8.15 g of C₂H₂.
4019K Express your answer as a nuclear equation.
Answer:
[tex]_{19} ^{40} K[/tex] → [tex]_{20} ^{40} Ca[/tex] + [tex]_{-1} ^{0} e[/tex] + ¯v
Explanation:
[tex]_{19} ^{40} K[/tex] is an unstable potassium isotope which has the capacity to undergo beta decay. During the decay process, it transforms to calcium atom with a release of beta particle and an antineutrino.
The required nuclear equation is:
[tex]_{19} ^{40} K[/tex] → [tex]_{20} ^{40} Ca[/tex] + [tex]_{-1} ^{0} e[/tex] + ¯v
The calcium formed due to this process is a stable atom.
How many doubtful digit(s) is/are allowed in any measured quantity?
(Only 3 choices.)
A.) 1
B.) 2
C.) zero
Answer:
zero
Explanation:
I I think one should be so accurate with measurements and experiments
Nitrogen and hydrogen react to form ammonia, like this:N2(g)+3H2(g)→2NH3(g)Use this chemical equation to answer the questions below.Suppose 135, mmol of N₂ and 405, mmol of H₂ are added to an empty flask, How much N₂ will be in the flask at equilibrium? a. Noneb. Some, but less than 135, mmol.c. 135,mmold. More than 135, mmol.Suppose 235, mmol of NH₃ are added to an empty flask, How much N₂ will be in the flask at equilibrium? a. Noneb. Some, but less than 118, mmol.c. 118,mmold. More than 118, mmol.
Answer:
Option A is correct, there will be no N2 left in the flask
Explanation:
Step 1 : Data given
Number of moles of N2 = 135 mmol = 0.135 mol
Number of moles of H2 = 405 mmol = 0.405 mol
Step 2: The reaction
N2(g)+3H2(g)→2NH3(g)
Step 3:
For 1 mol N2 we need 3 moles H2 to produce 2 moles NH3
Both will completely react. There is no limiting reactant.
There will be produce 0.270 moles NH3.
Option A is correct, there will be no N2 left in the flask
When 2-methyl-3-hexene is treated with Cl2 in methanol, three products are formed (neglecting stereoisomers). Draw curved arrows to show the movement of electrons in this step of the reaction mechanism.
Answer:
Explanation:
The structural formula of 2-methyl-3-hexene is drawn in the attached image below. After then, the three possible structures were drawn and the mechanism reaction.
From the mechanism shown, methanol deprotonates methoxide proton and neutralizes the positive charge to form methoxide. This is followed by the movement of electrons that takes place from the region of higher electron density to lower electron density.
What would you expect to observe when Br2 reacts with 2-butyne?
Answer:
I expect to observe a change in colour from reddish brown to a colourless solution
Explanation:
Bromine (Br2) attacks the electron rich carbon-carbon triple bond in but-2-yne, an alkyne to form an initial product 2, 3 dibromobut-2-ene; which reacts with excess bromine to form a final product 2,2,3,3 -tetrabromobutane.
The reaction occurs in two steps. On approaching but-2-yne, bromine molecule becomes polarised forming an induced dipole containing a bromonium ion.
Br - Br → Br+ - Br-
The bromonium ion (Br+) formed then attacks the carbon - carbon triple bond to form the initial product
2,3- dibromobut-2-ene
CH2-C≡C-CH2 + Br+ →
CH2 - CBr =CBr-CH2
(2,3- dibromobut-2-ene)
Which in the presence of excess bromine gives the final product
2,2,3,3 - tetrabromobutane.
CH2 - CBr =CBr-CH2 + Br2 →
CH3 -CBr2-CBr2 - CH3
2,2,3,3 - tetrabromobutane.
A visible change in colour from the reddish-brown colour of Bromine to a colourless solution is observed during the reaction.
Which statement is true about how scientists draw conclusions from data?
A. Scientists do not allow others to make conclusions about their data.
B. Teams of scientists never share their data to help other teams draw conclusions.
C. Any two scientists will always come to the same conclusion about a data set.
D. Two scientists may have different underlying assumptions that lead them to different conclusions about the same data.
Answer:
D. Two scientists may have different underlying assumptions that lead them to different conclusions about the same thing.
Explanation:
It's all about how a person analyzes data. Some do it mathmatically while others do it logically. By doing it different ways, you may still come to the same conclusion, despite working at the problem in a different way.
What are the concentrations of hydronium and hydroxide ions in a solution with pH 2.6?
Please help omg. Ive been stuck for 15 minutes
Answer:
The concentrations of hydronium and hydroxide ions in a solution with pH 2.6 are 2.51*10⁻³ and 3.98*10⁻¹² respectively.
Explanation:
pH is a measure of the acidity or alkalinity of an aqueous solution. The pH indicates the concentration of hydrogen ions present in certain solutions. Mathematically it is defined as the opposite of the base 10 logarithm or the negative logarithm of the activity of hydrogen ions, whose equation is
pH= -log [H⁺]
So, being pH= 2.6 and replacing in the definition of pH:
2.6= -log [H⁺]
[tex][H^{+} ]=10^{-2.6}[/tex]
[H⁺]=2.51*10⁻³
pOH is a measure of the concentration of hydroxide ions (OH⁻). The sum between the pOH and the pH results in 14:
pOH + pH= 14
So, being pH= 2.6:
pOH + 2.6= 14
pOH= 14 - 2.6
pOH= 11.4
The pOH is defined as the negative logarithm of the activity of the hydroxide ions. That is, the concentration of OH⁻ ions:
pOH= - log [OH⁻]
Being pOH= 11.4 and replacing
11.4= -log [OH⁻]
[tex][OH^{-} ]=10^{-11.4}[/tex]
[OH⁻]= 3.98*10⁻¹²
The concentrations of hydronium and hydroxide ions in a solution with pH 2.6 are 2.51*10⁻³ and 3.98*10⁻¹² respectively.
What is determined by calculating the slope of the position versus time graph distance
Answer:
Determining the Slope on a p-t Graph. It was learned earlier in Lesson 3 that the slope of the line on a position versus time graph is equal to the velocity of the object. ... If the object has a velocity of 0 m/s, then the slope of the line will be 0 m/s. The slope of the line on a position versus time graph tells it all.
Explanation:
#carryonlearning
To insert a thermometer into an adapter, use ______ to prepare the thermometer. Then, hold the thermometer ______ the adapter and _____ the thermometer into the adapter.
Answer:
mineral oil; close to; slowly turn
Explanation:
Temperature can be defined as a measure of the degree of coldness or hotness of a physical object. It is measured with a thermometer and its units are Celsius (°C), Kelvin (K) and Fahrenheit (°F).
Generally, temperature measures the average kinetic energy of particles in a particular substance.
A thermometer can be defined as a device used for measuring the temperature (degree of hotness or coldness) of a body or substance is. It is a thin glass having a bulb on one of its end and typically contains either colored alcohol or mercury.
A thermometer adapter is used with a temperature probe in the distillation process, in order to determine readings.
To insert a thermometer into an adapter, use mineral oil to prepare or make suitable the thermometer. Then, hold the thermometer close to the adapter and slowly turn the thermometer into the adapter.
g You observed the formation of several precipitates in the Reactions in Solution lab exercise. Identify the precipitate in each of the following reactions: a. The yellow precipitate formed in the reaction between KI and Pb(NO3)2 is . b. The white precipitate formed in the reaction between BaCl2 and H2SO4 is . c. The brown precipitate formed in the reaction between NaOH and FeCl3 is . d. The blue precipitate formed in the reaction between CuSO4 and NaOH is .
Answer:
For a: Lead iodide is a yellow precipitate.
For b: Barium sulfate is a white precipitate.
For c: Ferric hydroxide is a brown precipitate.
For d: Copper (II) hydroxide is a blue precipitate.
Explanation:
Precipitation reaction is defined as the reaction where a solid precipitate (solid substance) is formed at the end of the reaction. It is insoluble in water.
For the given options:
For (a):The chemical reaction between KI and lead (II) nitrate follows:
[tex]2KI(aq)+Pb(NO_3)_2(aq)\rightarrow PbI_2(s)+2KNO_3(aq)[/tex]
The iodide of lead is generally insoluble in water. Thus, lead iodide is a yellow precipitate.
For b:The chemical reaction between barium chloride and sulfuric acid follows:
[tex]BaCl_2(aq)+H_2SO_4(aq)\rightarrow BaSO_4(s)+2HCl(aq)[/tex]
The sulfate of barium is insoluble in water. Thus, barium sulfate is a white precipitate.
For c:The chemical reaction between NaOH and ferric chloride follows:
[tex]3NaOH(aq)+FeCl_3(aq)\rightarrow Fe(OH)_3(s)+3NaCl(aq)[/tex]
The hydroxide of iron is insoluble in water. Thus, ferric hydroxide is a brown precipitate.
For d:The chemical reaction between NaOH and copper sulfate follows:
[tex]CuSO_4+2NaOH\rightarrow Cu(OH)_2+Na_2SO_4[/tex]
The hydroxide of copper is insoluble in water. Thus, copper (II) hydroxide is a blue precipitate.
(a) The yellow precipitate formed in the reaction between KI and Pb(NO3)2 would be PbI2 according to the equation:
[tex]Pb(NO_3)_2(aq) + 2KI(aq) ---> PbI2(s) + 2KNO_3(aq)[/tex]
(b) The white precipitate formed in the reaction between BaCl2 and H2SO4 would be BaSO4 according to the equation:
[tex]BaCl_2 (aq) + H_2SO_4 (aq) ---> BaSO_4 (s) + 2 HCl (aq)[/tex]
(c) The brown precipitate formed in the reaction between NaOH and FeCl3 would be Fe(OH)3 according to the equation:
[tex]FeCl_3 (aq) + NaOH (aq) ---> Fe(OH)_3 (s) + NaCl (aq)[/tex]
(d) The blue precipitate formed in the reaction between CuSO4 and NaOH would be Cu(OH)2 according to the equation:
[tex]CuSO_4(aq) + 2 NaOH (aq) ---> Cu(OH)_2 (s) + Na_2SO_4 (aq)[/tex]
More on precipitation reaction can be found here: https://brainly.com/question/24846690
Which substrate is used in the last step of glycolysis
Pyruvate Kinase
Pyruvate Kinase performs a substrate level phosphorylation on ADP to generate an ATP and pyruvate, the final product of glycolysis.
PK dificiency is transmitted in an autosomal recessive disorder in which both alleles must contain the mutated gene, PK-LR.
Hope it helps you! ＼(^ᴥ^)／
Question 65 pts
(07.02 MC)
During a reaction, ΔH for reactants is −750 kJ/mol and ΔH for products is 920 kJ/mol. Which statement is correct about the reaction? (5 points)
Group of answer choices
It is endothermic because the energy required to break bonds in the reactants is less than the energy released when the products are formed.
It is endothermic because the energy required to break bonds in the reactants is greater than the energy released when the products are formed.
It is exothermic because the energy required to break bonds in the reactants is less than the energy released when the products are formed.
It is exothermic because the energy required to break bonds in the reactants is greater than the energy released when the products are formed.
Answer:
It is endothermic because the energy required to break bonds in the reactants is less than the energy released when the products are formed
Explanation:
A reaction may be endothermic or exothermic. In an endothermic reaction, energy is absorbed by the process while in an exothermic process energy is given out by the process.
Recall that the enthalpy change of a reaction = enthalpy of products - enthalpy of reactants
Hence, where the energy required to break bonds in the reactants is less than the energy released when the products are formed, the reaction is endothermic.
For an endothermic reaction, the enthalpy change of the reaction is positive.
In this case, enthalpy of reaction = 920 - (-750) = 1670 kJ/mol
Explain the sample prep for IR
Answer:
) Making a sandwich To prepare a liquid sample to IR analysis, firstly place a drop of the liquid on the face of a highly polished salt plate (such as NaCl, AgCl or KBr), then place a second plate on top of the first plate so as to spread the liquid in a thin layer between the plates, and clamps the plates together.
1.rain pours from the sky
2.leaves of the plant dried
3.fluffy clouds form in the sky
4.bathing suit dries after swim
5.water puddles disappear
A.Evaporation
B.Condensation
C.Precipitation
D.Transpiration
Yan po pag pipilian
Answer:
1.Precipitation
2.Transpiration
3.Condensation
4.Evaporation
5.Evaporation
3.Condensation
Explanation:
Rain pours from the sky occurs due to the process of precipitation, leaves of the plant dried due to the process of transpiration in which the water is evaporated from the body of plant, fluffy clouds form in the sky occurs in the process of condensation, bathing suit dries after swim is due to evaporation in which water is removed and goes into the atmosphere and water puddles disappear due to the process of evaporation. Evaporation is the removal of water from the any surface whereas transpiration is the removal of water from plant body parts.
Many chemistry problems result in equations of the form
1.77 X100.298-z)
When this equation is solved, the two values of the unknown are ________ and ________
Answer:
When this equation is solved, the two values of the unknown are 0.0643 and -0.082
Explanation:
Given
[tex]1.77 * 10^{-2} = \frac{x^2}{0.298 - x}[/tex] --- the actual equation
Required
The values of x
We have:
[tex]1.77 * 10^{-2} = \frac{x^2}{0.298 - x}[/tex]
Cross Multiply
[tex]1.77 * 10^{-2} * (0.298 - x)= x^2[/tex]
Multiply both sides by 100
[tex]1.77 * (0.298 - x)= 100x^2[/tex]
Open bracket
[tex]0.52746 - 1.77x= 100x^2[/tex]
Rewrite as:
[tex]100x^2 + 1.77x - 0.52746 =0[/tex]
Using quadratic formula:
[tex]x = \frac{-b \± \sqrt{b^2 - 4ac}}{2a}[/tex]
Where:
[tex]a = 100; b = 1.77; c = -0.52746[/tex]
So, we have:
[tex]x = \frac{-1.77 \± \sqrt{1.77^2 - 4*100*- 0.52746 }}{2*100}[/tex]
[tex]x = \frac{-1.77 \± \sqrt{214.1169}}{2*100}[/tex]
[tex]x = \frac{-1.77 \± 14.63}{200}[/tex]
Split
[tex]x = \frac{-1.77 + 14.63}{200}\ or\ x = \frac{-1.77 - 14.63}{200}[/tex]
[tex]x = \frac{12.86}{200}\ or\ x = \frac{-16.40}{200}[/tex]
[tex]x = 0.0643\ or\ x = -0.082[/tex]
Why ethanol is used in pectin extraction
Explanation:
is responsible for interrupting the interaction between pectins and solvent molecules
The element antimony has two stable isotopes, antimony-121 with a mass of 120.90 amu and antimony-123 with a mass of 122.90 amu. From the atomic weight of Sb = 121.76 one can conclude that: ________
antimony-123 has the highest percent natural abundance
most antimony atoms have a mass of 121.76 amu
antimony-121 has the highest percent natural abundance
both isotopes have the same percent natural abundance
Answer:
antimony-121 has the highest percent natural abundance
Explanation:
percent natural abundance;
121.76 = 120.90 x + 122.90 (1 - x)
121.76 = 120.90 x + 122.90 - 122.90x
121.76 = -2x + 122.90
121.76 - 122.90 = -2x
x= 121.76 - 122.90/ -2
x= 0.57
Where x and 1 - x refers to the relative abundance of each of the isotopes
Percent natural abundance of antimony-121 = 57 %
Percent natural abundance of antimony-123 = (1 - 0.57) = 43%
Let us remember that isotopy refers to a phenomenon in which atoms of the same element have the same atomic number but different mass numbers. This results from differences in the number of neutrons in atoms of the same element.
We can clearly see that antimony-121 has the highest percent natural abundance.
A 15.4 mL aliquot of 0.204 MH3PO4(aq) is to be titrated with 0.17 MNaOH(aq). What volume (mL) of base will it take to reach the equivalence point?
Answer:
55.44L of the 0.17M NaOH are required
Explanation:
Phosphoric acid, H3PO4, reacts with NaOH as follows:
H3PO4 + 3NaOH → Na3PO4 + 3H2O
Where 1 mole of H3PO4 reacts with 3 moles of NaOH
To solve this question we need to find the moles of H3PO4 in the aliquot. Using the balanced equation we can find the moles of NaOH and its volume with the concentration (0.17M) as follows:
Moles H3PO4:
15.4mL = 0.0154L * (0.204mol/L) = 0.00314 moles H3PO4
Moles NaOH:
0.00314 moles H3PO4 * (3mol NaOH / 1mol H3PO4) = 0.009425moles NaOH
Volume NaOH:
0.009425moles NaOH * (1L/0.17moles NaOH) = 0.05544L 0.17M NaOH =
55.44L of the 0.17M NaOH are requiredDo you think a single property is sufficient for conclusively identifying a substance?
Answer:
No
Explanation:A single property is insufficient for identifying a substance
What is the empirical formula for a compound if 300.00 g of it is known to contain 82.46224 g of molybdenum, 45.741 g of chlorine and the rest is bromine
Answer:
MoClBr₂
Explanation:
First we calculate the mass of bromine in the compound:
300.00 g - (82.46224 g + 45.741 g) = 171.79676 gThen we calculate the number of moles of each element, using their respective molar masses:
82.46224 g Mo ÷ 95.95 g/mol = 0.9594 mol Mo45.741 g Cl ÷ 35.45 g/mol = 1.290 mol Cl171.79676 g Br ÷79.9 g/mol = 2.150 mol BrNow we divide those numbers of moles by the lowest number among them:
0.9594 mol Mo / 0.9594 = 11.290 mol Cl / 0.9594 = 1.34 ≅ 12.150 mol Br / 0.9594 = 2.24 ≅ 2Meaning the empirical formula is MoClBr₂.
