Answer:
-1.82 °C
Explanation:
Step 1: Given data
Mass of NaCl (solute): 33.9 gMass of water (solvent): 578 g = 0.578 kgFreezing point depression constant for water (Kb): -1.82 °C/mStep 2: Calculate the molality of the solution
We will use the following expression.
m = mass of solute / molar mass of solute × kg of solvent
m = 33.9 g / 58.44 g/mol × 0.578 kg
m = 1.00 m
Step 3: Calculate the freezing point depression (ΔT)
The freezing point depression is a colligative property that, for a non-dissociated solute, can be calculated using the following expression:
ΔT = Kb × m
ΔT = -1.82 °C/m × 1.00 m
ΔT = -1.82 °C
A mixture is prepared using 27.00 mL of a 0.0758 M weak base (pKa=4.594) , 27.00 mL of a 0.0553 M weak acid (pKa=3.235) and 1.00 mL of 1.25×10−4 M HIn and then diluting to 100.0 mL, where HIn is the protonated indicator. The absorbance measured at 550 nm in a 5.000 cm cell was 0.1102 . The molar absorptivity (????) values for HIn and its deprotonated form In− at 550 nm are 2.26×104 M−1cm−1 and 1.53×104 M−1cm−1 , respectively. What is the pH of the solution?
Answer:
pH = 4.164
Explanation:
The first process is to find the initial moles for the base (B) & the acid (HA)
i.e.
[tex]= \dfrac{27 mL \times 0.0758 \ moles \ \ of \ B}{1000 \ mL}[/tex]
[tex]=0.0020466[/tex]
[tex]\simeq 2.047\times 10^{-3} \ moles \ of \ B[/tex]
[tex]= \dfrac{27 mL \times 0.0553 \ moles \ \ of \ HA}{1000 \ mL}[/tex]
[tex]=0.0014931[/tex]
[tex]\simeq 1.493\times 10^{-3} \ moles \ of \ HA[/tex]
The acid with base reaction is expressed as;
HA + B → A⁻ + HB⁺
to 1.493 × 10⁻³ 2.047 × 10⁻³ - -
- 1.493 × 10⁻³ 1.493 × 10⁻³ 1.493 × 10⁻³ 1.493 × 10⁻³
0 5.54 × 10⁻⁴ 1.493 × 10⁻³ 1.493 × 10⁻³
From observation; both the acid & base weak
Given that:
The pKa for base = 4.594
The pKa for acid = 3.235
Recall that;
pKa = -log Ka
So; Ka = [tex]\mathbf{10^{-Ka}}[/tex]
By applying this:
For Base; Ka = [tex]10^{-4.594}[/tex] = 2.5468 × 10⁻⁵
For Acid: Ka = [tex]10^{ -3.235}[/tex] = 5.821 × 10⁻⁴
After the reaction; we have the base with its conjugate acid & conjugate base of acid; Thus, since the conjugate acid of the base possesses a higher value of K, it is likely it would be the one to define the pH of the solution.
By analyzing the system, we have:
HB⁺ + H₂O ↔ B + H₃O⁺
[tex]\dfrac{1.493\times 10^{-3}}{0.1 \ L}[/tex] [tex]\dfrac{5.54\times 10^{-4}}{0.1 \ L}[/tex]
to 0.01493 M 0.00554 M
- x x x
0.01493 - x 0.00554 - x x
Thus;
[tex]2.5468 \times 10^{-5} = \dfrac{(0.00554 -x)\times x}{(0.01493-x)}[/tex]
Using the common ion effect;
0.00554 - x [tex]\simeq[/tex] 0.00554 &
0.01493 - x [tex]\simeq[/tex] 0.01493
∴
[tex]x = \dfrac{2.5468 \times 10^{-5} \times 0.01493}{0.00554}[/tex]
x = [H₃O⁺] = 6.8635 × 10⁻⁵
∴
pH = -log(6.8635 × 10⁻⁵)
pH = 4.164
A log has a density of .8 g/cm³. What will happen to this log in freshwater, which has a density of 1.0 g/cm³?
It will sink.
It will float.
It will move deeper.
It will decrease in density.
Explanation:
Objects with a lower density will float while objects with a higher density will sink.
Since 0.8g/cm³ < 1.0g/cm³,
The log will float in freshwater.
Conservation of mass to balance the following reaction. Na2S+ KI= NaI+ K2S
Answer:
1+2=2+1 is the answer for the question
help please I need help with these two questions answer truthfully get brainliest?!!
Answer:
1. 3x-3=18
Value of x=7
2. 4x-5=23
value of x=7
Answer:
b 7 for one
a 3 for two
Explanation:
Which phrase describes one type of freshwater wetland?
2
acidic areas found in northern climates
reservoirs created by dams at the end of rivers
areas of high elevation that feed into river systems
small streams that flow into larger streams and wetlands
Answer:
The correct answer is D
Explanation:
Wetlands are environments that are either submerged under water or are frequently wet. Marshes, swamps, bogs, and fens are examples of freshwater wetlands. Here small streams flow into larger streams and wetlands. The correct option is D.
Ecosystems in freshwater wetlands are impacted by transient or ongoing flooding. They are essential habitats for fauna (including migratory species), play a significant role in the regulation of water flow and water quality to entire catchments, and offer shelter for fauna during droughts.
In tropical and subtropical areas, mangrove swamps are coastal wetlands. In brackish to saline tidal waters, they are distinguished by halophytic (salt-loving) trees, shrubs, and other plants.
Thus the correct option is D.
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Jill is recovering from the Flu. At lunchtime, she shares her water bottle with her friend Dara. The next day,
Dara is sick. Which type of Disease is the Flu
Answer: I think its a virus
Explanation: Viruses spread form person to person just like any virus so if I'm correct the disease is a virus
Magnesium has a density of 1.738 g/cmº at 25°C. What is the mass of a block of
magnesium that has a volume of 743 cm??
Answer:
87.50g(1cm^3/1.1738g)=50.345 cm^3
Explanation:
volume units id in cubic centimeters
How does adding a lone pair affect the position of existing atoms and lone pairs
Answer:
How does adding a lone pair affect the position of existing atoms and lone pairs? It decreases the angles between the atoms - the atoms are moving closer because they are being repelled further away from the lone pairs then they are from the other atoms
Explanation:
hope it helps!
Type the correct answer in the box. Express your answer to three significant figures.
A balloon is filled with 0.250 mole of air at 35°C. If the volume of the balloon is 6.23 liters, what is the absolute pressure of the air in the balloon?
Answer:
102.807 kPa
Explanation:
There are some assumptions to be made in the answer. The air inside the balloon acts as an ideal gas at a given temperature conditions.
Using the combined ideal gas equation.
P= absolute pressure of the air inside the balloon.
V= volume of air inside the balloon (6.23 L= 6.23 * 10⁻³ m³)
n= moles of gas(air). (0.250 mol)
R= Universal gas constant ( 8.314 J / mol·K)
T= Temperature in Kelvin
T= 35 + 273.15 = 308.15 K
P= 102.807 * 10³ Pa
P= 102.807 kPa
Someone plz help me write notes (images attached)
Answer:
I'm not going to give you notes but I'm going to give you a tip for notes take what you think is the most important thing about the text and basically paraphrase it into your own words if that helps
How do balanced equations demonstrate the law of conservation of mass?
Answer:
Every chemical equation adheres to the law of conservation of mass, which states that matter cannot be created or destroyed. ... When an equal number of atoms of an element is present on both sides of a chemical equation, the equation is balanced.
Explanation:
so have a great day
ln a particular genetic cross, the probability of the offspring having a certain trait is 3/4
Which percentage represents this probability?
O 25%
O 50%
O 75%
O 100%
Answer:
75%
Explanation:
3/4 is 75% if you multiply by 25
How is continental crust different from oceanic crust?
A: Oceanic crust is thicker and more dense.
B: Oceanic crust is thinner and more likely to sink.
C: Continental crust is thicker and more likely to sink.
D: Continental crust is more dense and lighter.
Answer:
b
Explanation:
google lol ur welcome
B: Oceanic crust is thinner and more likely to sink.
6. Which scientific law is best demonstrated by the reaction shown in the diagram?
2H2 + O2-2H20
Hydrogen Oxygen Water
ALA
law of universal gravitation
law of angular momentum
law of conservation of energy
law of conservation of mass
Answer:
law of conservation of mass
Explanation:
According to the law of conservation of mass, mass is neither created nor destroyed.
This is actually the law that guides the balancing of chemical reaction equations.
On the left side we have four atoms of hydrogen and two atoms of oxygen. Exactly the same number of atoms of each element is seen on the right hand side in accordance with the law of conservation of mass.
The decomposition of ozone, O3, to oxygen, O2, is an exothermic reaction. What is the sign of q?
Answer:
The sign is negative (-)
Explanation:
it shows that heat was give off to the surrounding
Gold III Bromide is heated in a flask filled with chlorine gas.
The reactants of this reaction are:
I
The type of reaction is:
The products of this reaction are:
Answer:
detail is given below.
Explanation:
Chemical equation:
AuBr₃ + Cl₂ → AuCl₃ + Br₂
Balanced chemical equation:
2AuBr₃ + 3Cl₂ → 2AuCl₃ + 3Br₂
The reactants of this chemical reaction are,
AuBr₃
Cl₂
The product of this chemical reaction is,
AuCl₃
Br₂
Reaction type:
The reaction type is single replacement reaction.
Single replacement:
It is the reaction in which one elements replace the other element in compound.
AB + C → AC + B
In a similar way chlorine replace the bromine and form gold(III) chloride and bromine gas.
(plsss help meh.) Describe how you could find the density of a gold crown.
Answer:
Below! ;)
Explanation:
The formula for finding density is:
Mass/Volume
So for example I have a cube, it has a mass of about 20 grams (not weight) and it's dimensions are about an inchxinchxinch. So basically it is a 20 gram cubic inch cube.
So to find it's density I have to divide mass(=20)/Volume(=1 inch^3). or simplified, 20 ÷ 1 = 20
So the density of my cube is 20..
Hope this helps!
Have a nice day!
If you find my answer helpful
Pls consider marking my answer as Brainliest! It would mean a lot!
Step 1: (slow)
Step 2: NO3(g) + CO(g) + NO2(g) + CO2(g) (fast)
Overall: NO2(g) + CO(g) + NO(g) + CO2(g)
A two-step reaction mechanism is proposed for a gas-phase reaction, as represented above. Which of the following correctly identifies both the chemical equation for step 1 and the rate law for the overall reaction?
A) The chemical equation for step 1 is 2 NO2(g) → NO(g) + NO3(g), and the rate law is rate = (NO,].
B) The chemical equation for step 1 is NO2(g) + CO(g) + NO(g) + CO2(g), and the rate law is rate = [NO2][CO).
C) The chemical equation for step 1 is NO3(g) + 2 CO(g) + NO(g) + 2 CO2(g), and the rate law is rate = [NO2][CO).
D) The chemical equation for step 1 is NO3(g) + NO2(g) + 2 CO(g) + NO(g) + NO2(g) + 2 CO2(g), and the rate law is rate = [NO3][NO2][CO]".
Answer:
The chemical equation for step 1 is 2 NO2(g) → NO(g) + NO3(g), and the rate law is rate = k[NO2]^2
Explanation:
We know that the rate determining step is the slowest step in a sequence of non elementary reactions.
As we can see, the first reaction is slow so it is the rate determining step. From here we obtain the rate equation.
Also, the specie NO3 is absent in the overall reaction equation indicating that it is merely an intermediate produced in step 1 and used up in step 2.
The chemical equation for step 1 is [tex]2 NO_2(g) \rightarrow NO(g) + NO_3(g)[/tex], and the rate law is [tex]rate = k[NO_2]^{2}[/tex].
The rate -determining step is the slowest step in a sequence of non -elementary reactions. The first reaction is slow so it is the rate determining step. From here we obtain the rate law.
Also, the specie [tex]NO_3[/tex] is absent in the overall reaction equation indicating that it is merely an intermediate produced in step 1 and used up in step 2.
So, the chemical equation for step 1 is [tex]2 NO_2(g) \rightarrow NO(g) + NO_3(g)[/tex], and the rate law is [tex]rate = k[NO_2]^{2}[/tex].
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What is rate of reaction?
Answer:
The reaction rate or rate of reaction is the speed at which a chemical reaction takes place. Reaction rate is defined as the speed at which reactants are converted into products. Reaction rates can vary dramatically.
Explanation:
PLS MAKE ME AS BRAINLIST
Heeellllpppp ASAP ......
Answer:
I saw B, he vented SUS
Explanation:
Iodoethane Is the answer.
Which stage in a frog's life cycle is most similar to a plant seed?
A Eggs
B. Tadpole
C. Froglet
D. Adult Frog
bond energy is the greatest for?. a: Ch4 b: O2 c: N2 d: Cl2
It's answer is c. N2
The maximum bond energy is of N2 because N2 molecule is formed by 3 covalent bonds and O2 molecule is formed by 2 covalent bonds.
Hope it helps :)
HELPPPPPP
is this
1:conduction
2:radiation
3:convection
Answer:
Radiation
Explanation:
Sun rays shine on earth. Thats radiation.
How many moles of Fe2+ are there in a 2.0g sample that is 80% by mass of FeCl2?
The number of moles of [tex]Fe^{2+}[/tex] in the [tex]2.0g[/tex] sample of [tex]FeCl_{2}[/tex] is [tex]0.0157[/tex] moles.
The following points should be noted about the number of moles:
The number of moles of any substance can be calculated using the mass and molar mass of the substance. [tex]n = \frac{mass}{molarmass}[/tex], where n is the number of moles.Mass of the sample given as [tex]2.0g[/tex] and the molar mass of the sample as [tex]126.75g/mol[/tex].
Therefore, the number of moles of [tex]Fe^{2+}[/tex]is obtained by dividing the mass by the molar mass.
Hence the number of moles is obtained as [tex]0.0175[/tex] moles.
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If Oxygen were to gain 2 electrons, the new electron configuration for the oxide ion
would be similar to which neutral atom?
A. Stays the same as Oxygen
B. Sulfur
C. Neon
D. Carbon
please help me i will give brain list
Answer:
a. pentane = C5H12
b. Heptane = C7H16
c. Hexyne = C6H10
d. Octene = C8H16
e. Nonane = C9H20
Hope it helps.
1-pentene
Molecular Formula C5H10
Condensed Structural FormulaCH2=CH(CH2)2CH3
Melting Point (°C)–138
Boiling Point (°C)30
2- heptane is the straight-chain alkane with the chemical formula H3C(CH2)5CH3 or C7H16, and is one of the main components of gasoline (petrol).
According to the following reaction, if 69 g of KCIO3, decomposes, how many grams of oxygen will form:
2KCIO3 + 2KCl + 302
Answer:
28.8g
Explanation:
I think your chemical equation should be:
2KClO3 → 2KCl +3O2
Number of moles of KClO3
[tex] = \frac{mass}{molar \: mass} [/tex]
[tex] = \frac{69}{39 + 35.5 + 3(16)} [/tex]
[tex] = 0.6mol[/tex]
From the equation,
2 mol of KClO3 : 3 mol of 02
So...
0.6 mol of KClO3 : 0.9 mol of O2
Number of moles of O2= 0.9mol
So the mass of O2 formed = number of moles× molar mass
= 0.9 × 2(16)
= 28.8g
If 69 gram of KClO₃ decomposes then 27.036 grams of oxygen will form.
What is Stoichiometry ?Stoichiometry helps us use the balanced chemical equation to measure the quantitative relationship and it is to calculate the amount of product and reactants that are given in a reaction.
What is Balanced Chemical Equation ?The balanced chemical equation is the equation in which the number of atoms on the reactant side is equal to the number of atoms on the product side in an equation.
The given balanced equation is
2KClO₃ → 2KCl + 3O₂
According to Stoichiometry, x gram of oxygen will form
= [tex]69\ \text{g of}\ KClO_{3} \times \frac{1\ \text{mol}\ KClO_{3}}{122.55\ g\ KClO_{3}} \times \frac{3\ \text{mol}\ O_2}{2\ \text{mol}\ KClO_{3}} \times \frac{32\ g\ O_2}{1\ \text{mol}\ O_2}[/tex]
= 27.036 grams of Oxygen
Thus from the above conclusion we can say that If 69 gram of KClO₃ decomposes then 27.036 grams of oxygen will form.
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Based on details from "Thomas Edison: The Master of Improvement,” how did Joseph Swan and Thomas Edison differ?
Swan liked to experiment, while Edison did not.
Swan was very inventive, while Edison was not.
Swan invented a working lightbulb, while Edison did not.
Swan received a formal education, while Edison did not.
Answer:
The correct answer is D. Swan received a formal education, while Edison did not.
Explanation:
I did the Unit Test :)
"Thomas Edison: The Master of Improvement,” is about Thomas Edison. Joseph Swan received a formal education, while Thomas Edison did not. Thus, option D is correct.
Who was Thomas Edison?Thomas Edison was a known American inventor that invented the incandescent light bulb, the camera, phonograph, etc. He used electricity and worked very hard to invent the lightbulb. He received no formal education and believed in self-improvement.
He was a great inventor and fantastic improver that performed various experiments to invent the greatest inventions. Joseph Swan, on the other hand, was a physicist that developed the incandescent light bulb even before Edison.
He invented dry photographic plates and electric lightbulbs. He received proper formal education and sued Edison for the lightbulb patent infringement. He used carbon paper filaments, unlike Edison's metallic filaments in the bulb.
Therefore, in option D. both the scientists, Joseph Swan and Thomas Edison differed in receiving formal education.
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which event would most likely lead to a thunderstorm giving brainliest
Answer:
A
Explanation:
Took at test on this and my teacher said it was right, hopefully I remembered right, also I answered ur other question like this I think lol
Which of the following is an essential condition for a combustion reaction?
A - Oxygen is a product.
B - Oxygen is a reactant.
C - Carbon dioxide is a product.
D - Carbon dioxide is a reactant.
Answer:
oxygen is a reactant.
Explanation:
Combustion is the reaction with atmospheric oxygen forming carbon dioxide and water. Therefore, the essential condition is option B oxygen as a reactant.
What is combustion?Combustion is a type of reaction in which a molecule or compound reacts with atmospheric oxygen producing carbon dioxide and water. Combustion reaction is exothermic thus, evolves heat during reaction.
The general chemical equation for a combustion reaction can be written as:
[tex]\rm M + nO_{2} \rightarrow xH_{2}O + y CO_{2}[/tex]
Where, M be a reactant.
Combustion is an aerobic process that is only taking place in presence of oxygen. Hydrocarbon gases easily undergo combustion forming heat energy and they are used as fuels propellants.
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