13. (6C) An unknown chemical has the
following properties: it is a white crystal,
reacts with water, and has a high boiling
point. Which of these properties is
physical?
A White color only
B Reacts with water, high
boiling point
C Reacts with water only
D White color, high boiling
point
Answer: it is B
Explanation:
A 7.27-gram sample of a compound is dissolved in 250. grams of benzene. The freezing point of this solution is 1.02°C below that of pure benzene. What is the molar mass of this compound? (Note: Kf for benzene = 5.12°C/m.) Ignore significant figures for this problem. Group of answer choices 36.5 g/mol 146 g/mol 292 g/mol 5.79 g/mol 73.0 g/mol
Answer:
The correct answer is 146 g/mol
Explanation:
Freezing point depression is a colligative property related to the number of particles of solute dissolved in a solvent. It is given by:
ΔTf = Kf x m
Where ΔTf is the freezing point depression (in ºC), Kf is a constant for the solvent and m is the molality of solution. From the problem, we know the following data:
ΔTf = 1.02ºC
Kf = 5.12ºC/m
From this, we can calculate the molality:
m = ΔTf/Kf = 1.02ºC/(5.12ºC/m)= 0.199 m
The molality of a solution is defined as the moles of solute per kg of solvent. Thus, we can multiply the molality by the mass of solvent in kg (250 g= 0.25 kg) to obtain the moles of solute:
0.199 mol/kg benzene x 0.25 kg = 0.0498 moles solute
There are 0.0498 moles of solute dissolved in the solution. To calculate the molar mass of the solute, we divide the mass (7.27 g) into the moles:
molar mass = mass/mol = 7.27 g/(0.0498 mol) = 145.9 g/mol ≅ 146 g/mol
Therefore, the molar mass of the compound is 146 g/mol
What is the dependent variable? Be specific. *
If a teacher washes the tops of the student
desks with rubbing alcohol daily, the
spread of germs in the classroom may be
diminished.Be specific when you write your answer HELPPPPP I NEED IT ASAP!
Please help
What is an element
Answer:
An element is atoms with the same number of protons.
Explanation:
Protons, electrons, and neutrons.
a water sample is found to have a cl- content of 100ppm as nacl what is the concentration of chloride in moles per liter
Answer:
The concentration of chloride ion is [tex]2.82\times10^{-3}\;mol/L[/tex]
Explanation:
We know that 1 ppm is equal to 1 mg/L.
So, the [tex]Cl^-[/tex] content 100 ppm suggests the presence of 100 mg of [tex]Cl^-[/tex] in 1 L of solution.
The molar mass of [tex]Cl^-[/tex] is equal to the molar mass of Cl atom as the mass of the excess electron in [tex]Cl^-[/tex] is negligible as compared to the mass of Cl atom.
So, the molar mass of [tex]Cl^-[/tex] is 35.453 g/mol.
Number of moles = (Mass)/(Molar mass)
Hence, the number of moles (N) of [tex]Cl^-[/tex] present in 100 mg (0.100 g) of [tex]Cl^-[/tex] is calculated as shown below:
[tex]N=\frac{0.100\;g}{35.453\;g/mol}=2.82\times 10^{-3}\;mol[/tex]
So, there is [tex]2.82\times10^{-3}\;mol[/tex] of [tex]Cl^-[/tex] present in 1 L of solution.
Which number represetns a coefficient?
2
3
4
7
Suppose you are studying the kinetics of the iodine-catalyzed decomposition of hydrogen peroxide. 2 H 2 O 2 ⟶ 2 H 2 O + O 2 If you determine the initial rate is 7.50 × 10 − 4 M/s when [ H 2 O 2 ] = 0.546 M and [ K I ] = 0.212 M , what is the rate constant? Assume that the order of both reactants is 1.
Answer:
[tex]k=6.48x10^{-3}M^{-1}s^{-1}[/tex]
Explanation:
Hello.
In this case, based on the given information, we can write the rate law as shown below:
[tex]r=k[H_2O_2][KI][/tex]
Since the overall order of reaction is 2 being 1 for reach reactant. Thus, by knowing the initial rate and concentrations, the rate constant turns out:
[tex]k=\frac{r}{[H_2O_2][KI]}=\frac{7.50x10^{-4}M/s}{0.546M*0.212M}\\ \\k=6.48x10^{-3}M^{-1}s^{-1}[/tex]
Best regards!
The rate constant, k is [tex]6.48x10^{-3}M^{-1}s^{-1}[/tex]
Rate law:The rate law should be
[tex]r = k[H_2O_2]{KI}[/tex]
Since the total order of the reaction is 2 being 1 for reach reactant. So, by knowing the beginning rate and concentrations, the rate constant turns out:
[tex]k = \frac{r}{k[H_2O_2]{KI}} = \frac{7.50x10^{-4}M/s}{0.546M\times 0.212M}[/tex]
k = [tex]6.48x10^{-3}M^{-1}s^{-1}[/tex]
Learn more about reactants here; https://brainly.com/question/21029530
Is lead a representative metal or transitional metal?
Answer:
It's a representative metal
Explanation: Transitional metals are metals of various chemical elements and have valence electrons—i.e., electrons that can participate in the formation of chemical bonds.
How many molecules are there in 985 mL of nitrogen at 0.0 degrees C and 1.00x10^-6 mm Hg?
(It would be better if work or steps to solve problem are given but if not its fine).
Answer:
3.48 x 1013 N2 molecules
step-by-step explanation:
Lets set up our equation first
P = 1.00 x 10-6 mm Hg T = 0.0° C + 273 = 273 K
We are given the V = 985 mL ,
R = 0.0821 L·atm/mol·K
Now use the ldeal gas law, but we are solving n, amount of substanvce
PV = nRT, we will change this equation to ;
n = PV/RT
n = 1.00 x 10-6 mm x 1 atm/760 mm x 985 mL x 1 L/103
mL/
(0.0821 L·atm/mol·K x 273 K) = 5.78 x 10-11 moles N2
nmolecules = 5.78 x 10-11 moles N2 x 6.02 x 1023 N2 molecules/1 mol N2
An object accelerates 12.0 m / s ^ 2 when a force of 6.0 Newtons is applied to it what is the mass of the object
Answer:
The answer is 0.5 kgExplanation:
The mass of the object can be found by using the formula
[tex]m = \frac{f}{a} \\ [/tex]
where
f is the force
a is the acceleration
From the question we have
[tex]m = \frac{6}{12} = \frac{1}{2} \\ [/tex]
We have the final answer as
0.5 kgHope this helps you
Answer:
The mass of object is 0.5 Kg.
Explanation:
Given data:
Acceleration of object = 12.0 m/s²
Force on object = 6.0 N
Mass of object = ?
Solution:
Formula:
F = m×a
F = force
m = mass
a = acceleration
Now we will put the values in formula.
6.0 N = m × 12.0 m/s²
m = 6.0 N / 12.0 m/s²
( N = kg.m/s²)
m = 0.5 kg
The mass of object is 0.5 Kg.
Cementation is part of the process of
A. igneous intrusion
B. lithification
C. igneous extrusion
D. metamorphism
SUBMIT
Answer:
The correct answer is b.
Explanation:
hope this helps u
Answer:
Bryna is correct it is B
Explanation:
What is the gravitational potential energy, in joules, of a 75 kg person that is 1000.0
meter above the ground? Gravitational acceleration = 9.81 m/s2
Answer:
In this example, a 3 kilogram mass, at a height of 5 meters, while acted on by Earth's gravity would have 147.15 Joules of potential energy, PE = 3kg * 9.81 m/s 2 * 5m = 147.15 J. 9.81 meters per second squared (or more accurately 9.80665 m/s 2 ) is widely accepted among scientists as a working average value for Earth's gravitational pull.
Explanation:
Antoine Lavoisier correctly characterize as an element?
Ten moles of hydrogen are allowed to react with 6 moles of oxygen. How much water will be
obtained from reaction on complete consumption of one gas?
Answer:
10 moles of water are produced,
Explanation:
Given data:
Moles of H = 10 mol
Moles of O = 6 mol
Water obtained = ?
Solution:
Balance chemical equation:
2H₂ + O₂ → 2H₂O
Now we will compare the moles of H₂ and O₂ with water from balance chemical equation.
H₂ : H₂O
2 : 2
10 : 10
O₂ : H₂O
1 : 2
6 : 2×6 = 12
Number of moles of water produced by hydrogen are less so hydrogen will be limiting reactant and it will limit the yield of water thus, 10 moles of water are produced.
Atomic radius is....
O The tendency for an atom to attract electrons
The energy required to remove an electron
O The energy required to add an electron
O The distance from the nucleus to the last orbital
What are the two ways
that heat is measured?
Answer:
heat is mesured in calories and also joules
Explanation:
Explain how plucking occurs
Answer:
plucking is usually extracting hair
Explanation:
example: pluck the chicken feathers
pluck my brows
A student reacts 5.0 g of sodium with 10.0 g of chlorine and collect 5.24 g of sodium chloride. What is the percent yield of this combination reaction
Answer: The percent yield of this combination reaction is 41.3 %
Explanation : Given,
Mass of [tex]Na[/tex] = 5.0 g
Mass of [tex]Cl_2[/tex] = 10.0 g
Molar mass of [tex]Na[/tex] = 23 g/mol
Molar mass of [tex]Cl_2[/tex] = 71 g/mol
First we have to calculate the moles of [tex]Na[/tex] and [tex]Cl_2[/tex].
[tex]\text{Moles of }Na=\frac{\text{Given mass }Na}{\text{Molar mass }Na}[/tex]
[tex]\text{Moles of }Na=\frac{5.0g}{23g/mol}=0.217mol[/tex]
and,
[tex]\text{Moles of }Cl_2=\frac{\text{Given mass }Cl_2}{\text{Molar mass }Cl_2}[/tex]
[tex]\text{Moles of }Cl_2=\frac{10.0g}{71g/mol}=0.141mol[/tex]
Now we have to calculate the limiting and excess reagent.
The balanced chemical equation will be:
[tex]2Na+Cl_2\rightarrow 2NaCl[/tex]
From the balanced reaction we conclude that
As, 2 mole of [tex]Na[/tex] react with 1 mole of [tex]Cl_2[/tex]
So, 0.217 moles of [tex]Na[/tex] react with [tex]\frac{0.217}{2}=0.108[/tex] moles of [tex]Cl_2[/tex]
From this we conclude that, [tex]Cl_2[/tex] is an excess reagent because the given moles are greater than the required moles and [tex]Na[/tex] is a limiting reagent and it limits the formation of product.
Now we have to calculate the moles of [tex]NaCl[/tex]
From the reaction, we conclude that
As, 2 mole of [tex]Na[/tex] react to give 2 mole of [tex]NaCl[/tex]
So, 0.217 mole of [tex]HCl[/tex] react to give 0.217 mole of [tex]NaCl[/tex]
Now we have to calculate the mass of [tex]NaCl[/tex]
[tex]\text{ Mass of }NaCl=\text{ Moles of }NaCl\times \text{ Molar mass of }NaCl[/tex]
Molar mass of [tex]NaCl[/tex] = 58.5 g/mole
[tex]\text{ Mass of }NaCl=(0.217moles)\times (58.5g/mole)=12.7g[/tex]
Now we have to calculate the percent yield of this reaction.
Percent yield = [tex]\frac{\text{Actual yield}}{\text{Theoretical yield}}\times 100[/tex]
Actual yield = 5.24 g
Theoretical yield = 12.7 g
Percent yield = [tex]\frac{5.24g}{12.7g}\times 100[/tex]
Percent yield = 41.3 %
Therefore, the percent yield of this combination reaction is 41.3 %
(5x10^3) + (4.3x10^4)=
Answer:
48000
Explanation:
maths
Answer:
48000
Explanation:
(5x10^3) = 5 × 1000 = 5000
(4.3x10^4) = 4.3 × 10000 = 43000
5000 + 43000 = 48000
PLSSS HELP Match each image to the
correct step of meiosis. PLS HELP
Answer:
Explanation:
Here you go!! Hope this helps.
In which Earth system does the rock cycle take place?
cryosphere
atmosphere
geosphere
biosphere
Answer:
geosphere
Explanation:
geo means rocks this is the area
hope this helps dude
how many moles are in a 4.2 gram gold sample
A 50.0 g sample of an unknown substance, initially at 20.2 °C, was heated with 1.55 kJ of energy. The final temperature of the substance was 125.0 °C. Determine the specific heat of this substance.
Answer:
0.296j/g⁰c
Explanation:
we have the following information from this question before us.
mass iv substance = 50grams
we have initial temperature ti = 20.2⁰c
final temperature = 125⁰c
the energy that was provided = 155kj
we proceed with this formula
energy = mcΔT
1.55x10³ = 50 x c x (125-20.2)
1.55x10³ = c x 50gm x 104.8k
we divide through to get c
c = 1.55x10³/50g x 104.8
c = 0.296J/g⁰c
that is the specific heat of this substance.
thank you!
HELP ME ASAP!
Under the Law of Multiple Proportions, Carbon Dioxide has a ratio of 2.666 g
Oxygen for every 1 g Carbon. Given this, how much oxygen is present in a sample
of carbon dioxide that has 16 g of carbon?
Answer:
In carbon dioxide, on the right, there is 2.666 g of oxygen for every gram of carbon. So the ratio of oxygen in the two compounds is 1:2, a small whole number ratio
please mark me as the brainliest answer and please please pleaseeee follow me.
Which pair of elements would most likely have a similar arrangement of outer
electrons and have similar chemical behaviors?
boron and aluminum
helium and fluorine
carbon and nitrogen
chlorine and oxygen
Answer:
Boron and Aluminum
Explanation:
If you write the electron configuration for boron and aluminum, you get:
[tex]1s^22s^22p^1[/tex] for boron and [tex]1s^22s^22p^63s^23p^1[/tex] for aluminum. Both have 3 valance electrons and has 2 electrons in a s-orbital and 1 in a p-orbital. These valance electron similarities are based on the column/group the elements are. Therefore, Boron and Aluminum have similar chemical behaviours and similar arrangement of outer/valance electrons.
In chemistry, one often uses a unit of charge known as the Faraday, F, which has the magnitude of the charge of 1 mole of electrons. How many faradays of charge does that correspond to
Answer:
1 Faraday
Explanation:
This question seeks to test proper understanding of Faraday's second law of electrolysis which states when the same quantity electricity passes through a solution of different electrolytes, the mass of the substance deposited is directly proportional to there chemical equivalence.
This law hints at the charges of ions being the chemical equivalence and also been represented as the unit for the quantity of electricity in faraday, F. Hence, a metal with the charge of 1+ can be displaced by 1F (which is equal to 96, 500 coloumbs). This charge also represents one molecule of electron, thus 1 faraday corresponds to one mole of electrons.
NOTE: It should be noted that a metal with the charge of 2+ can be displaced by 2F and so on.
How would you calculate an object's mechanical energy?
a. Add its kinetic and potential energies. b. Multiply its kinetic and potential energies.
c. Subtract its kinetic energy from its kinetic energy.
d. Subtract its potential energy from its kinetic energy.
Answer:
You would add its kinetic and potential energies.
Explanation:
Hope this helps!! :)
Answer:
A) Add its kinetic and potential energies
Explanation:
I got it right on Edge 2022
The pOH of an aqueous solution of 0.480 M trimethylamine (a weak base with the formula (CH3)3N) is .
Answer:
Explanation:
Kb of (CH₃)₃N is 7.4 x 10⁻⁵
initial concentration of (CH₃)₃N a is .48 M
(CH₃)₃N + H₂O = (CH₃)₃NH⁺ + OH⁻
a - x x x
x² / (a - x ) = Kb
x is far less than a so a - x can be replaced by a .
x² / a = Kb
x² = a x Kb = .48 x 7.4 x 10⁻⁵ = 3.55 x 10⁻⁵ = 35.5 x 10⁻⁶
x = 5.96 x 10⁻³
pOH = - log ( 5.96 x 10⁻³ )
= 3 - log 5.96
= 3 - .775
= 2.225
which element Shows very similar chemical properties to barium?
If 1.02 g of nickel reacted with 750. mL of 0.112 M hydrobromic acid, how much of each will be present at the end of the reaction if you captured the gas in a 2.50 L vessel at 30 C
Answer:
35.1% is percent yield
Explanation:
Full question: Assume no volume change. If you formed 0.0910 atm of gas, what is the percent yield?
The reaction that is occurring is:
Ni + 3HBr → NiBr₃ + 3/2H₂(g)
First, we will determine moles of Ni and HBr to determine limiting reactant and theoretical yield
Using ideal gas law, we can determine the moles of hydrogen formed. Thus, we can find percent yield:
Moles Ni (Molar mass: 58.69g/mol):
1.02g * (1mol / 58.69g) = 0.01738moles Ni
Moles HBr:
0.750L * (0.112mol/L) = 0.084 moles of HBr.
For a complete reaction of the 0.084 moles of HBr you need:
0.084mol HBr * (1 mole Ni / 3 moles HBr) = 0.028 moles of Ni.
As there are just 0.01738 moles of Ni, the Ni is limiting reactant. Assuming a theoretical yield, moles of H₂ produced are:
0.01738moles Ni * (3/2 H₂ / 1 mol Ni) = 0.02607 moles H₂
Now, moles of H₂ produced are:
PV = nRT
PV/RT = n
Where P is pressure (0.0910atm)
V is volume (2.50L)
R is gas constant (0.082atmL/molK)
T is absolute temperature in Kelvin (30°C + 273.15 = 303.15K)
And n are moles
PV/RT = n
0.0910atm*2.50L/0.082atmL/molK*303.15K = n
0.00915 moles = n
And percent yield (Produced moles / Theoretical moles * 100) is:
0.00915 moles / 0.02607moles =
35.1% is percent yield