Answer:
His results will be skewed because there was more water than stock solution. Which would cause the percentage solution to be less than 50% therefore the density would be less than the actual value.
Explanation:
The solution will have percentage less than that of 50%. Therefore the density would be less than the actual value.
Suppose there should be 50 mL of the solution, and he added 60 mL. So 10 mL of the solution is added more.
Suppose the mass of the solute is m.
Originally, the density is = [tex]$\frac{m}{50}$[/tex] [tex]\left(\frac{\text{mass}}{\text{volume}}\right)[/tex]
Now after adding extra 10 mL , the density becomes [tex]$\frac{m}{60}$[/tex].
Therefore, [tex]$\frac{m}{50}>\frac{m}{60}$[/tex]
So the density decreases when we add more solution.
You are given 12.2 g of NaOH. Determine the number of moles of NaOH.
0.5 mol
O 0.31 mol
O 487.96 mol
mass = 12.2 g NaOH
Required:n
Solution:Step 1: Calculate the molar mass of NaOH.
molar mass = (22.99 g/mol × 1) + (16.00 g/mol × 1) + (1.008 g/mol × 1)
molar mass = 39.998 g/mol
Step 2: Calculate the number of moles of NaOH.
n = mass / molar mass
n = 12.2 g / 39.998 g/mol
n = 0.31 mol
Therefore, the number of moles of NaOH is 0.31 mol.
#ILoveChemistry
Answer:
ANSWERRRRRRRRRRRR BBBBBBBBB
Explanation:
Calculate the molar mass of NaOH.
molar mass = (22.99 g/mol × 1) + (16.00 g/mol × 1) + (1.008 g/mol × 1)
molar mass = 39.998 g/mol
Step 2: Calculate the number of moles of NaOH.
n = mass / molar mass
n = 12.2 g / 39.998 g/mol
n = 0.31 mol
Therefore, the number of moles of NaOH is 0.31 mol.
. Diatomic chlorine and sodium hydroxide (lye) are commodity chemicals produced in large quantities, along with diatomic hydrogen, via the electrolysis of brine, according to the following unbalanced equation:
NaCl(aq)+ H2O(l) → NaOH (aq) + H2(g) + Cl2(g)
Write balanced molecular, complete ionic, and net ionic equations for this process.
Answer:
See explanation
Explanation:
The molecular equation is depicted below;
The balanced molecular reaction equation is;
2 NaCl (aq) + 2 H2O (l) → 2 NaOH (aq) + Cl2 (g) + H2 (g)
The complete ionic equation is;
2Na^+(aq) + 2Cl^-(aq) + 2H2O(l) ---> 2Na^+(aq) + 2OH^-(aq) + Cl2(g) + H2(g)
Hence, net Ionic equation;
2Cl^-(aq) + 2H2O(l) ---> 2OH^-(aq) + Cl2(g) + H2(g)
A chemistry student must write down in her lab notebook the concentration of a solution of sodium thiosulfate. The concentration of a solution equals the mass of what's dissolved divided by the total volume of the solution.
Answer:
A chemistry student must write down in her lab notebook the concentration of a solution of sodium thiosulfate. The concentration of a solution equals the mass of what's dissolved divided by the total volume of the solution.
Explanation:
The concentration of a solution can be measured in terms of molarity.
The molarity of a solution can be defined as the number of moles of solute present in the total volume of the solution.
The number of moles of solute is the ratio of mass of solute to molar mass of solute.
Hence,
[tex]Molarity=\frac{mass of solute}{molar mass of solute} * \frac{1}{volume of solution in L.}[/tex]
A molecular compound has the following empirical formula: CH2O. The molar mass of the empirical formula is g. Write your answer using 3 significant figures. If the molar mass of the molecular compound is 180.0 g/mol, write the molecular formula of the compound.
Answer:
Empirical formula has a molar mass of 30.01g/mol and molecular formula is C₆H₁₂O₆
Explanation:
Molar mass of a molecule is the sum of the molar mass of each atom. In CH2O we have:
1C = 1*12.01g/mol = 12.01g/mol
2H = 2*1g/mol = 2g/mol
1O = 1*16g/mol = 16g/mol
Empirical formula of CH2O is:
12.01g/mol + 2g/mol + 16g/mol = 30.01g/mol
As the molecular compound has a molar mass of 180.0g/mol the molecular formula is:
180.0g/mol / 30.01g/mol = 6 times the empirical formula. That is:
C₆H₁₂O₆When 10.0 g of sulfur is combined with 10.0 g of oxygen, 20.0 g of sulfur dioxide is formed. What mass of oxygen would be required to convert 10.0 g of sulfur into sulfur trioxide?
Answer:
Actually, we can answer the problem even without the first statement. All we have to do is write the reaction for the production of sulfur trioxide.
2 S + 3 O₂ → 2 SO₃
The stoichiometric calculations is as follows:
6 g S * 1 mol/32.06 g S = 0.187 mol S
Moles O₂ needed = 0.187 mol S * 3 mol O₂/2 mol S = 0.2805 mol O₂
Since the molar mas of O₂ is 32 g/mol,
Mass of O₂ needed = 0.2805 mol O₂ * 32 g/mol = 8.976 g O₂
what is the scientific name of lion
Answer:
the scientific name of lion is
Panthera leo
* Use the periodic table
How many grams of O2 are in a 5.0 mol of the element?
80 g
16 g
160 g
(NH4)2SO4(aq)+SrCl2(aq)→
Liquid nitrogen becomes a gas when it is poured out of its container. The nitrogen is
Answer:
compressable
Explanation:
as liquid nitrogen came out from container the force exerted on it which changes it into liquid ends making it gas
liquid nitrogen boils at 77 K or -196° C
what is the theoretical yield of Mg(s) + O2(g) → MgO(s)
will give brainliest fakes will be reported
A student collecting CaCO3 produced by the reaction of Na2CO3(aq) and CaCl2(aq) obtains a percent yield of 81%. Choose all of the following observations that could explain the low yield.
a. The combined reactants were not stirred before filtering the precipitate.
b. The student did not completely dry the precipitate before weighing it.
c. The precipitate was not washed prior to drying.
d. A rubber policeman was not used to scrape precipitate from the beaker.
e. The filter paper was not wetted with water prior to filtering the precipitate.
Answer:
a, d and e. are true.
Explanation:
The reaction that occurs is:
Na2CO3(aq) + CaCl2(aq) → CaCO3(s) + 2NaCl
In ideal conditions, the percent yield of the reaction must be 100%. All explanations about why the student could not collect all precipitate are right:
a. The combined reactants were not stirred before filtering the precipitate. Not stirring could not promote all the reaction. TRUE.
b. The student did not completely dry the precipitate before weighing it. If the student don't dry the precipitate, the mass of precipitate must be higher producing a percent yield > 100%. FALSE.
c. The precipitate was not washed prior to drying. Produce more mass. FALSE.
d. A rubber policeman was not used to scrape precipitate from the beaker. If the student doesn't collect all the precipitate the percent yield could be < 100%.. TRUE.
e. The filter paper was not wetted with water prior to filtering the precipitate. TRUE. If you don't wet the filter paper you can lose a part of precipitate from the walls of this one.
Using Hess’s law, what is the standard enthalpy of formation of manganese (II) oxide, MnO(s)?
With the help of hess's law:
ΔHf(MnO)=−248.9 kJ−12(272.0) kJ=−384.9 kJ(per mole) Δ H f ( M n O ) = − 248.9 k J − 1 2 ( 272.0 ) k J = − 384.9 k J ( p e r m o l e )
What is Hess's law?Hess's law of constant heat summation, also known simply as Hess' law, is a relationship in physical chemistry named after Germain Hess, a Swiss-born Russian chemist and physician who published it in 1840.
Moreover, hess's Law of Constant Heat Summation (or just Hess's Law) states that regardless of the multiple stages or steps of a reaction, the total enthalpy change for the reaction is the sum of all changes.
Therefore, hess' law is based on the state function character of enthalpy and the first law of thermodynamics. Energy (enthalpy) of a system (molecule) is a state function.
Learn more about hess's law:
https://brainly.com/question/14561923
#SPJ6
Epinephrine (adrenaline) is a hormone secreted into the bloodstream in times of danger and stress. It is 59.0% carbon, 7.15% hydrogen, 26.20% oxygen, and 7.65% nitrogen by mass and has a molar mass of 183 g/mol. Determine the empirical formula for Epinephrine.
Answer: The empirical and molecular formula for the given organic compound is [tex]C_9H_{13}O_3N[/tex]
Explanation:
Let the mass of the compound be 100 g
Given values:
% of C = 59.0%
% of H = 7.15%
% of O = 26.20%
% of N = 7.65%
Mass of C = 59.0 g
Mass of H = 7.15 g
Mass of O = 26.20 g
Mass of N = 7.65 g
The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)
To formulate the empirical formula, we need to follow some steps:
Step 1: Converting the given masses into moles.Molar mass of C = 12 g/mol
Molar mass of H = 1 g/mol
Molar mass of O = 16 g/mol
Molar mass of N = 14 g/mol
Putting values in equation 1, we get:
[tex]\text{Moles of C}=\frac{59.0g}{12g/mol}=4.917 mol[/tex]
[tex]\text{Moles of H}=\frac{7.15g}{1g/mol}=7.15 mol[/tex]
[tex]\text{Moles of O}=\frac{26.20g}{16g/mol}=1.6375 mol[/tex]
[tex]\text{Moles of N}=\frac{7.65g}{14g/mol}=0.546 mol[/tex]
Step 2: Calculating the mole ratio of the given elements.Calculating the mole fraction of each element by dividing the calculated moles by the least calculated number of moles that is 0.546 moles
[tex]\text{Mole fraction of C}=\frac{4.917}{0.546 }=9[/tex]
[tex]\text{Mole fraction of H}=\frac{7.15}{0.546 }=13[/tex]
[tex]\text{Mole fraction of O}=\frac{1.6375}{0.546 }=2.99\approx 3[/tex]
[tex]\text{Mole fraction of N}=\frac{0.546}{0.546 }=1[/tex]
Step 3: Taking the mole ratio as their subscripts.The ratio of C : H : O : N = 9 : 13 : 3 : 1
The empirical formula of the compound becomes [tex]C_9H_{13}O_3N_1=C_9H_{13}O_3N[/tex]
To calculate the molecular formula, the number of atoms of the empirical formula is multiplied by a factor known as valency that is represented by the symbol, 'n'.
[tex]n =\frac{\text{Molecular mass}}{\text{Empirical mass}}[/tex] .....(2)
We are given:
Mass of molecular formula = 183 g/mol
Mass of empirical formula = 183 g/mol
Putting values in equation 2, we get:
[tex]n=\frac{183g/mol}{183g/mol}=1[/tex]
Multiplying this valency by the subscript of every element of empirical formula, we get:
[tex]C_{1\times 9}H_{1\times 13}O_{1\times 3}N_{1\times 1}=C_9H_{13}O_3N[/tex]
Hence, the empirical and molecular formula for the given organic compound is [tex]C_9H_{13}O_3N[/tex]
Give the ground-state electron configuration for each of the following elements. After each atom is its atomic number in parentheses. (a) Potassium (19) (b) Neon (10)How many electrons are in the valence shell of each atom ? (a) Visited um (AI) (b) Oxygen (O) (c) Fluorine (F)
Answer:
(a) ₁₉K: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹
(b) ₁₀Ne: 1s² 2s² 2p⁶
---
(a) 3
(b) 6
(c) 7
Explanation:
We can state the ground-state electron configuration for each element following Aufbau's principle.
(a) ₁₉K: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹
(b) ₁₀Ne: 1s² 2s² 2p⁶
Second part
(a) Al belongs to Group 13 in the Periodic Table. It has 13-10=3 electrons in the valence shell.
(b) O belongs to Group 16 in the Periodic Table. It has 16-10=6 electrons in the valence shell.
(c) F belongs to Group 17 in the Periodic Table. It has 17-10=7 electrons in the valence shell.
A sample of gas contains 0.1800 mol of CO(g) and 0.1800 mol of NO(g) and occupies a volume of 23.2 L. The following reaction takes place:
2CO(g) + 2NO(g 2Co2(g) +N2(g)
Calculate the volume of the sample after the reaction takes place, assuming that the temperature and the pressure remain constant.
Answer:
The volume of the sample is 17.4L
Explanation:
The reaction that occurs requires the same amount of CO and NO. As the moles added of both reactants are the same you don't have any limiting reactant. The only thing we need is the reaction where 4 moles of gases (2mol CO + 2mol NO) produce 3 moles of gases (2mol CO2 + 1mol N2). The moles produced are:
0.1800mol + 0.1800mol reactants =
0.3600mol reactant * (3mol products / 4mol reactants) = 0.2700 moles products.
Using Avogadro's law (States the moles of a gas are directly proportional to its pressure under constant temperature and pressure) we can find the volume of the products:
V1n2 = V2n1
Where V is volume and n moles of 1, initial state and 2, final state of the gas
Replacing:
V1 = 23.2L
n2 = 0.2700 moles
V2 = ??
n1 = 0.3600 moles
23.2L*0.2700mol = V2*0.3600moles
17.4L = V2
The volume of the sample is 17.4LA 420 mL sample of a 0.100 M formate buffer, pH 3.75, is treated with 7 mL of 1.00 M KOH. What is the pH following this addition? (pKa for formic acid is 3.75)
Answer: The pH of the resulting solution will be 3.60
Explanation:
Molarity is calculated by using the equation:
[tex]\text{Molarity}=\frac{\text{Moles}}{\text{Volume}}[/tex] ......(1)
We are given:
Molarity of formic acid = 0.100 M
Molarity of potassium formate = 0.100 M
Volume of solution = 420 mL = 0.420 L (Conversion factor: 1 L = 1000 mL)
Putting values in equation 1, we get:
[tex]\text{Moles of formic acid}=(0.100mol/L\times 0.420L)=0.0420mol[/tex]
[tex]\text{Moles of potassium formate}=(0.100mol/L\times 0.420L)=0.042mol[/tex]
Molarity of KOH = 1.00 M
Volume of solution = 7 mL = 0.007 L
Putting values in equation 1, we get:
[tex]\text{Moles of KOH}=(1mol/L\times 0.007L)=0.007mol[/tex]
The chemical equation for the reaction of formic acid and KOH follows:
[tex]HCOOH+KOH\rightleftharpoons HCOOK+H_2O[/tex]
I: 0.042 0.007 0.042
C: -0.007 -0.007 +0.007
E: 0.035 - 0.049
Volume of solution = [420 + 7] = 427 mL = 0.427 L
To calculate the pH of the acidic buffer, the equation for Henderson-Hasselbalch is used:
[tex]pH=pK_a+ \log \frac{\text{[conjugate base]}}{\text{[acid]}}[/tex] .......(2)
Given values:
[tex][HCOOK]=\frac{0.049}{0.427}[/tex]
[tex][HCOOH]=\frac{0.035}{0.427}[/tex]
[tex]pK_a=3.75[/tex]
Putting values in equation 2, we get:
[tex]pH=3.75-\log \frac{(0.049/0.427)}{(0.035/0.427)}\\\\pH=3.75-0.146\\\\pH=3.60[/tex]
Hence, the pH of the resulting solution will be 3.60
Name the following ketone:
여 o
A. cyclohexyne
B. cyclohexanal
C. cyclohexanol
D. cyclohexanone
Answer:
It is D).cyclohexanone ( in acellus)
Explanation:
Cellulose and starch are examples of:
Select one:
a. monosaccharides
b. disaccharides
c. lipids
d. polysaccharides
Answer:
The choose (d)
d. polysaccharides
Calculate the new boiling point of a solution if 10.00 g of a non-ionizing compound (C3H5(OH)3) is dissolved in 90.00 g of H2O. Molar Mass of C3H5(OH)3 = 92.09 g/mol Kb = 0.51 oC/m (Answer must be in 4 sig fig. Do not include units in your answer).
Answer:
Boiling T° of solution = 100.6
Explanation:
Formula for elevation of boiling point is:
ΔT = Kb . m . i
where ΔT means Boiling T° of solution - Boiling T° of pure solvent
Our solute is a non ionizing compound.
i = 1, because it is a non ionizing compound. i, indicates the ions dissolved in solution.
m = molality (moles of solute dissolved in 1 kg of solvent)
90 g of solvent = 0.09 kg of solvent
We convert mass of solute to moles (by the molar mass):
10 g . 1 mol /92.09 g = 0.108 moles
m = 0.108 mol /0.09 kg = 1.21 m
Let's replace data: Boiling T° of solution - 100°C = 0.51 °C/m . 1.21 m . 1
Boiling T° of solution = 0.51 °C/m . 1.21 m . 1 + 100°C
Boiling T° of solution = 100.6
What is the pH of a 1.0 x103 M KOH solution?
A. 11
B. 4.0
C. 10
D. 3.0
Answer:
Option A. 11
Explanation:
We'll begin by calculating the concentration of Hydroxide ion in the solution. This can be obtained as follow:
KOH (aq) —> K⁺(aq) + OH¯(aq)
From the balanced equation above,
1 mole of KOH produced 1 mole of OH¯.
Therefore, 1×10¯³ M KOH will also produce 1×10¯³ M OH¯.
Next, we shall determine the pOH of the solution. This can be obtained as follow:
Concentration of Hydroxide ion [OH¯] = 1×10¯³ M
pOH =?
pOH = –Log [OH¯]
pOH = –Log 1×10¯³
pOH = 3
Finally, we shall determine the pH of the solution. This can be obtained as follow:
pOH = 3
pH =?
pH + pOH = 14
pH + 3 = 14
Collect like terms
pH = 14 – 3
pH = 11
Therefore, the pH of the solution is 11
Which one is the dependent variable in distance, force, or work
Answer:
Work
Explanation:
Formula for work is given by;
Work = force × distance.
It is clear from this formula that Work depends on force and distance.
This means that force and distance are independent of the workdone and so they are classified as independent variables while work will be the dependent variable.
What is the IUPAC name of the following compound?
OH
s
Answer:
2-isopropyl-4-methylphenol.
Explanation:
Hey there!
In this case, according to the given information, it turns out possible for us to assign the appropriate IUPAC name of the given compound, by considering that the phenol stands for the parent chain and we have isopropyl methyl radicals which the former is called first due to the alphabet consideration.
In such a way, the name would be 2-isopropyl-4-methylphenol.
Regards!
Calculate the pressure exerted by 40 g of oxygen enclosed in a 1litre flask at 25°C. (0=16) (3 Marks)
Answer:
I don't know sorry siso
Explanation:
I don't know
describe how lyophobic sols are synthesize by dispersion method
Explanation:
For preparing lyophobic sol, the substance in bulk is broken down into particles of colloidal dimensions (Dispersion) or aggregating smaller particles into particles of colloidal dimensions (condensation).
Ch3-ch2-o-ch2-ch2-och3
Explanation:
ethoxypropane
Ch3-ch2-o-ch2-ch2-och3
Which of the following equations is not balanced?
A.
C5H12(1)
+
802(8)
5CO2(8)
+ 6H2O(g)
B.
H3PO4(aq)
+ 3NaOH(aq)
Na3PO4(aq) + 3H20(1)
C.
PC15(8)
+ 3H2O(g)
H3PO46
+ 5HCl(aq)
D.
Pb(NO3)2(aq)
+ 2HCl(aq)
PbCl2(s)
+ 2HNO3(aq)
Answer:
The answer is C.
Explanation:
In the chemical equation in C, there are 15 Carbon atoms and 1 Phosphorus atom in PC15, and 3 Hydrogen atoms and 6 Oxygen atoms in 3H2O on the left hand side. On the right hand side, there are 3 Hydrogen atoms, 1 Phosphorus atom and 46 Oxygen atoms in H3PO46, and 5 Hydrogen atoms and 5 Chlorine atoms in 5HCl.
Therefore, tallying up, there are 6 Oxygen atoms on the left hand side and 46 Oxygen atoms on the right hand side. This means the chemical equation in C is unbalanced.
Hope this helped!
The constitutional isomer of ethanol, dimethyl ether (CH3OCH3), is a gas at room temperature. Suggest an explanation for this observation.
Answer:
Because of its weak intermolecular forces.
Explanation:
Hello there!
In this case, according to the given description, it turns out possible for us to recall the chemical structures of both ethanol and dimethyl ether as follows:
[tex]CH_3CH_2OH\\\\CH_3COCH_3[/tex]
Thus, we can see that ethanol have London dispersion forces (C-C bonds), dipole-dipole forces (C-O bonds) and also hydrogen bonds (O-H bonds) which make ethanol a liquid due to the strong hydrogen bonds. On the other hand, we can see that dimethyl ether has just London and dipole forces, which are by far weaker than hydrogen bonding, that makes it unstable when liquid and therefore it tends to vaporize quite readily.
Regards!
Na lost an e- it shrank and the Cl+ grew in size. Does that say anything about the location of the electron before and after it was transferred
Answer:
48
Explanation:
Potassium Chlorate decomposes according to the reaction below.
2KClO3(s) 2KCl(s) + 3O2(g)
A 4.35 g sample of KClO3 is heated and the O2 gas produced by the reaction is collected in an evacuated flask. What is the volume of the O2 gas if the pressure of the flask is 0.75 atm and the gas temperature is 27oC? R=0.0821 (L*atm)/(mol*K)
Answer:
1.75L
Explanation:
Reaction of decomposition is:
2KClO₃(s) → 2KCl(s) + 3O₂(g)
We determine moles of salt:
4.35 g . 1 mol /122.55 g = 0.0355 moles
Ratio is 2:3. 2 moles of salt can produce 3 moles of oxygen
Then, our 0.0355 moles of chlorate may produce (0.0355 . 3)/ 2 = 0.0532 moles.
We have determined, moles of gas and we have data of pressure and temperature. To find out the volume, we apply the Ideal Gases Law:
We convert T° from °C to K → 27°C + 273 = 300K
P . V = n . R . T
0.75 atm . V = 0.0532 mol . 0.0821 L.atm/mol.K . 300K
V = (0.0532 mol . 0.0821 L.atm/mol.K . 300K) / 0.75 atm
V = 1.75 Liters
Which tasks can be used to start a descriptive investigation
Answer:
The tasks which form the preliminaries to a descriptive investigation are: Making careful objective observations. Asking the relevant scientific questions.