Answer:
pH = 2.69
Explanation:
The complete question is: An analytical chemist is titrating 182.2 mL of a 1.200 M solution of nitrous acid (HNO2) with a solution of 0.8400 M KOH. The pKa of nitrous acid is 3.35. Calculate the pH of the acid solution after the chemist has added 46.44 mL of the KOH solution to it.
The reaction of HNO₂ with KOH is:
HNO₂ + KOH → NO₂⁻ + H₂O + K⁺
Moles of HNO₂ and KOH that react are:
HNO₂ = 0.1822L × (1.200mol / L) = 0.21864 moles HNO₂
KOH = 0.04644L × (0.8400mol / L) = 0.0390 moles KOH
That means after the reaction, moles of HNO₂ and NO₂⁻ after the reaction are:
NO₂⁻ = 0.03900 moles KOH = moles NO₂⁻
HNO₂ = 0.21864 moles HNO₂ - 0.03900 moles = 0.17964 moles HNO₂
It is possible to find the pH of this buffer (Mixture of a weak acid, HNO₂ with the conjugate base, NO₂⁻), using H-H equation for this system:
pH = pKa + log₁₀ [NO₂⁻] / [HNO₂]
pH = 3.35 + log₁₀ [0.03900mol] / [0.17964mol]
pH = 2.69???????????????????????
Answer:
c or b
Explanation:
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Which of the following is an example of a molecule? A. Cl(chlorine) B. HCl (hydrochloric acid) C. Hydrogen D. Bromine
Answer:
hydrogen
Explanation
a molecule of hydrogen is the simplest possible molecule . its consists of two protons and two electrons heid together by electrostatic forces. like atomic hydrogen the assemblage can exist in a number of energy levels
When scientists are ready to publish the results of their experimentation, why is it important for them to include a description of the procedures they used?
To qualify for publication, scientists are required to submit lists of materials and procedures.
To be accepted by other scientists, results of experiments must be published in journals that require descriptions of procedures.
To be valid, experiments must be able to be repeated by other scientists.
Answer: To be valid, experiments must be able to be repeated by other scientists.
Answer:
Answer is C) To be valid, experiments must be able to be repeated by other scientists.
Explanation:
According to the lab guide, which changes below will you look for in order to test the hypothesis? Check all that apply. changes in shape or size color changes whether changes are easily reversible temperature changes formation of precipitates or gases changes of state (gas, liquid, or solid)
The correct options are: changes in shape or size, color changes, formation of precipitates or gases, and whether changes are easily reversible.
According to the lab guide, the following changes below will be looked for in order to test the hypothesis: changes in shape or sizecolor changesformation of precipitates or gaseswhether changes are easily reversibleThese changes are the characteristics that will be observed in order to test the hypothesis in the lab. Furthermore, temperature changes and changes of state (gas, liquid, or solid) may also occur and can be observed while testing the hypothesis.
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Answer:
A,B,E,F
Explanation:
The density of titanium is 4.51 g/cm^3. what is the volume (in cubic inches) of 3.0 lb of titanium?
Who created the planetary model of the atom?
Question 1 options:
Democritus
Dalton
Rutherford
Bohr
if 9.00g grams of gas are enclosed in a 50.00 L vessel at 273.15K and 2.000 atmospheres of pressure , what is the molar mass of the gas? what gas is this?
Answer: 4.88 g/mol. and helium
Explanation:
To find the molar mass of the gas, we can use the ideal gas law equation which is PV=nRT where:
P = pressure = 2.000 atm
V = volume = 50.00 L
n = number of moles
R = gas constant = 0.08206 L·atm/K·mol
T = temperature = 273.15 K
First, we need to find the number of moles of the gas:
PV = nRT
n = PV/RT
n = (2.000 atm)(50.00 L)/(0.08206 L·atm/K·mol)(273.15 K)
n = 1.844 mol
Now, we can find the molar mass of the gas by dividing its mass by the number of moles:
molar mass = mass/number of moles
mass = 9.00 g
molar mass = 9.00 g/1.844 mol
molar mass = 4.88 g/mol
Therefore, the molar mass of the gas is 4.88 g/mol.
To determine what gas this is, we can compare the molar mass of the gas to the molar masses of known gases. The molar mass of 4.88 g/mol is closest to that of helium (4.00 g/mol). Therefore, this gas is most likely helium.
7) How many molecules of CO2 are in 2.5 L at STP?
By using the ideal gas law and Avogadro's number, we find that there are approximately 6.72 × 10^22 molecules of CO2 in 2.5 L at STP.
To determine the number of molecules of CO2 in 2.5 L at STP (Standard Temperature and Pressure), we can use the ideal gas law and Avogadro's number.
Avogadro's number (N_A) is a fundamental constant representing the number of particles (atoms, molecules, ions) in one mole of substance. Its value is approximately 6.022 × 10^23 particles/mol.
STP conditions are defined as a temperature of 273.15 K (0 °C) and a pressure of 1 atmosphere (1 atm).
First, we need to convert the volume from liters to moles of CO2. To do this, we use the ideal gas law equation:
PV = nRT,
where P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant, and T is the temperature in Kelvin.
Since we have STP conditions, we can substitute the values:
(1 atm) × (2.5 L) = n × (0.0821 L·atm/(mol·K)) × (273.15 K).
Simplifying the equation:
2.5 = n × 22.4149.
Solving for n (the number of moles):
n = 2.5 / 22.4149 ≈ 0.1116 moles.
Next, we can calculate the number of molecules using Avogadro's number:
Number of molecules = n × N_A.
Number of molecules = 0.1116 moles × (6.022 × 10^23 particles/mol).
Number of molecules ≈ 6.72 × 10^22 molecules.
Therefore, there are approximately 6.72 × 10^22 molecules of CO2 in 2.5 L at STP.
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pOH of the 0.001M NaOH solution is
The pOH of the 0.001 M NaOH solution is approximately 3.
To determine the pOH of a solution, we need to know the concentration of hydroxide ions (OH-) in the solution.
In the case of a 0.001 M NaOH solution, we can assume that all of the NaOH dissociates completely in water to form Na+ and OH- ions. Therefore, the concentration of hydroxide ions in the solution is also 0.001 M.
The pOH is calculated using the equation:
pOH = -log[OH-]
Substituting the concentration of hydroxide ions, we have:
pOH = -log(0.001)
Using a calculator, we can evaluate the logarithm:
pOH ≈ 3
Therefore, the pOH of the 0.001 M NaOH solution is approximately 3.
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A runner completes a 400-meter race in 2.5 mins. What is the runner's average speed?
7. All physical forms of water (solid, liquid, and gas) make up the
a. atmosphere.
b. biosphere.
C. hydrosphere.
8. The living portion of the earth is contained within the
a. lithosphere.
b. biosphere.
C. hydrosphere.
9. The correct sequence of layers of the atmosphere from innermost to outermost is
a. troposphere--stratosphere--mesosphere--thermosphere.
b. mesosphere--stratosphere--thermosphere--troposphere.
c. thermosphere--stratosphere--mesosphere--troposphere.
10. Most of Earth's weather occurs in the
a. mesosphere.
b. troposphere.
C. stratosphere.
Answer:
C. Hydrosphere for 7
B. Biosphere for 8
Explanation: I am not sure about the rest of them.
The molecule cyanazine, once used as an herbicide, has now been phased out by the EPA because of its significant human toxicity. Add lone pairs, as needed, to the structure of cyanazine. Indicate the hybridization of the specified atoms. Be sure to consider any lone pairs you added to the structure. The structure of cyanazine has 5 atoms highlighted. Atom 1 is an N atom bonded to 2 C atoms and 1 H atom through single bonds. Atom 2 is an N atom bonded to one C atom through a single bond and one C atom through a double bond. Atom 3 is a C atom bonded to one C l atom and one N atom through a single bond and one N atom through a double bond. Atom 4 is a C atom that is bonded to three C atoms and one N atom through single bonds. Atom 5 is a C atom that is bonded to one C atom through a single bond and one N atom through a triple bond. What is the hybridization of atom 1
Answer:
Sp3
Explanation:
According to the question, atom 1 is an N atom bonded to 2 C atoms and 1 H atom through single bonds.
Whenever nitrogen is bonded to three atoms via single bonds (in this case two carbon atoms and one hydrogen atom) the nitrogen atom is sp3 hybridized and in tetrahedral geometry. The lone pair on nitrogen atom occupies one of the hybrid sp3 orbitals.
Cyanazine is used as an herbicide to control the growth of weeds and annual grasses. The herbicide has been phased out due to increased toxicity to the environment and humans.
The hybridization of the molecule is sp³.
The given information in the question suggests that Nitrogen (atom 1) to two Carbon atoms and single bonded to 1 hydrogen atom.
The nitrogen is bonded with three single bonds, two with carbon and one with a hydrogen bond.
Based on the given data, the hybridization of the molecule will be sp³ and will have tetrahedral geometry. The lone pair present on the nitrogen atom will occupy one of the hybrid sp³ orbitals.
Therefore, the sp3 hybridization of the cyanazine molecule will exist.
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Pre-Lab Assignment
1.
Describe the following trends in properties of oxides across Period 3.
(a)
(b)
Their appearance.
Their volatility
Their structure.
Their acid-base character
Their conductivity
(d)
Answer:
See explanation
Explanation:
From left to right, the oxides across period 3;
i) Period 3 oxides all appear white in colour. They are all crystalline solids and their melting points decrease from left to right.
ii) The volatility of period 3 oxides increases from left to right across the periodic table
iii) The metallic oxides on the right hand side adopt giant ionic structures. Silicon oxide which is in the middle of the period forms a giant covalent structure. Oxides of other elements towards the right hand side form molecular oxide structures.
iv) The acidity of oxides of period 3 increases from left to right. Metals on the left hand side form basic oxides while non-metals on the right hand side form acidic oxides. The oxide of aluminium in the middle is amphoteric.
v) The oxides of period 3 elements do not conduct electricity. However, the metallic oxides on the lefthand side conduct electricity in molten state. The non-metallic oxides on the right hand side are molecular hence they do not conduct electricity under any circumstance.
a gas has an initial volume of 3,480 mL and an initial temperature of - 70.0 C. what must be the temperature of the gas in kelvin if its volume is reduced to 2,450 mL
The temperature of the gas in Kelvin, after its volume is reduced to 2,450 mL, is approximately 143.27 K.
To determine the temperature of the gas in Kelvin after its volume is reduced, we can use the combined gas law, which relates the initial and final conditions of pressure, volume, and temperature for a given amount of gas.
The combined gas law equation is:
(P₁ * V₁) / T₁ = (P₂ * V₂) / T₂
Where P₁ and P₂ are the initial and final pressures, V₁ and V₂ are the initial and final volumes, T₁ is the initial temperature in Kelvin, and T₂ is the final temperature in Kelvin.
Given that the initial volume V₁ is 3,480 mL, the initial temperature T₁ is -70.0 °C (which needs to be converted to Kelvin), and the final volume V₂ is 2,450 mL, we can substitute these values into the equation.
To convert -70.0 °C to Kelvin, we add 273.15 to it, resulting in T₁ = 203.15 K.
Now we can solve for T₂:
(T₂ * V₁) / T₁ = V₂
T₂ = (V₂ * T₁) / V₁ = (2,450 mL * 203.15 K) / 3,480 mL
Simplifying the equation, we find:
T₂ ≈ 143.27 K
Therefore, the temperature of the gas in Kelvin, after its volume is reduced to 2,450 mL, is approximately 143.27 K.
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What is the density at 27 °C of 28.0 milliliters of a liquid that has a mass of 4.05 grams?
Answer:
The answer is 0.14 g/mLExplanation:
The density of a substance can be found by using the formula
\(density = \frac{mass}{volume} \\\)
From the question
mass = 4.05 g
volume = 28 mL
We have
\(density = \frac{4.05}{28} \\ = 0.1446428571...\)
We have the final answer as
0.14 g/mLHope this helps you
The relative atomic mass of aluminium is 27 and of oxygen is 16. The aluminium ore shown below contains 5.4kg of aluminium and 4.8kg of oxygen. What is the value of y?
Answer:
To find the value of y, we need to use the concept of molar ratios and the mole concept.
First, we need to calculate the number of moles of aluminum and oxygen in the given sample of ore. We can do this by dividing the mass of each element by its respective atomic mass:
Number of moles of aluminum = 5.4 kg / 27 g/mol = 200 moles
Number of moles of oxygen = 4.8 kg / 16 g/mol = 300 moles
Next, we can determine the ratio of the number of moles of aluminum to oxygen in the sample. This ratio is:
Aluminum : Oxygen = 200 : 300
Simplifying this ratio by dividing both sides by 100, we get:
Aluminum : Oxygen = 2 : 3
According to the chemical formula of aluminum oxide (Al2O3), it contains 2 atoms of aluminum for every 3 atoms of oxygen. Therefore, the sample of ore must contain a whole number of units of this chemical formula. Let the number of units of Al2O3 be y.
Then, we can set up the following equation to solve for y:
2 moles of aluminum * y = 200 moles of aluminum
3 moles of oxygen * y = 300 moles of oxygen
Simplifying each equation, we get:
y = 100
y = 100
Since both equations give the same value for y, we can conclude that the sample of ore contains 100 units of Al2O3. Therefore, the value of y is 100.
The H+ ion concentration of an aqueous solution is 1.0x10-8 M. What is the OH- ion concentration in the solution? Is this solution acidic, neutral, or basic?
Taking into account the definition of pH and pOH, the OH- ion concentration in the solution is 1×10⁻⁶ M and the solution is basic.
Definition of pHThe pH is a coefficient that indicates the degree of acidity or basicity of an aqueous solution and indicates the amount of hydrogen ions present in a solution or substance.
The pH is defined as:
pH= - log [H⁺]= - log [H₃O⁺]
Neutral pH is 7: if the number is higher, the solution is basic, and if it is lower, it is acidic.
Definition of pOHSimilarly, pOH indicates the amount of hydroxyl ions and is expressed as the logarithm of the concentration of OH⁻ ions, with the sign changed:
pOH= - log [OH⁻]
Relationship between pH and pOHThe relationship between pH and pOH can be established as:
pOH + pH= 14
[OH⁻] in this caseBeing [H⁺]=1×10⁻⁸ M, the pH is calculated as:
pH= - log (1×10⁻⁸ M)
Solving:
pH= 8
The solution is basic because the pH is greater than 7.
Being pH= 8, pOH is calculated as:
pOH + 8= 14
pOH= 14 - 8
pOH= 6
Replacing in the definition of pOH the concentration of OH⁻ ions is obtained:
- log [OH⁻]= 6
Solving:
[OH⁻]= 10⁻⁶
[OH⁻]=1×10⁻⁶ M
In summary, the [OH⁻] is 1×10⁻⁶ M.
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If I add water to 10mL of a 0.15M NaOH solution until the final volume is150mL, what will the molarity of the diluted solution be?
To solve this problem we need to remember the equation for dilution of solutions:
\(C_1V_1=C_2V_2\)Where C1 is the concentration of the first solution, V1 is the volumen of the first solution, C2 is the concentration of second solution and V2 is the concentration of the second solution.
We know from the text that C1=0.15M and V2 is 150ml, and they tell us that V2 is obtained by adding V1 10ml which we can express as the following expression:
\(V_2=V_{1\text{ }}+10ml\)Solving for V1 and using the data provided:
\(V_1=V_2-10ml=150ml-10ml=140ml\)Now we have all de data for solving the first equation, we have to solve for C2 and substitute:
\(C_2=\frac{C_1V_1}{V_2}=\frac{0.15\text{ M}\cdot140ml}{150ml}=0.14M\)Final concentration is 0.14M
✞how are snythetic detergents better than soap??⭐⭐㋛
Answer:
Advantages of synthetic detergents over soaps: Detergents can work with hard water too while soaps cannot. Synthetic detergents are stronger cleansing agents than soaps.
Explanation:
sorry if I'm wrong
How many atoms are in 6.78x1024 molecules of oxygen gas? PLEASE HELP WILL marK braNLIes
Balance the entire chemical
reaction using an atom inventory.
What is the correct whole
number coefficient for propane,
C3H8?
[?]C3H8+ [ 0₂
]CO2+[ ]H2O
The balanced chemical equation for the combustion of propane with oxygen is: C₃H₈ + 5O₂ → 3CO₂ + 4H₂O
To balance the equation, first balance the carbon atoms on both sides of the equation. There are three carbon atoms in the propane molecule and three in the carbon dioxide molecule, so balance the carbon atoms by putting a coefficient of 3 in front of the CO₂ molecule.
C3H8 + 5O2 → 3CO₂
Next, balance the hydrogen atoms. There are eight hydrogen atoms in the propane molecule and four in the water molecule, so balance the hydrogen atoms by putting a coefficient of 4 in front of the H₂O molecule.
C₃H₈ + 5O₂ → 3CO₂ + 4H₂O
Finally, balance the oxygen atoms. There are five oxygen atoms on the left side and 10 on the right side, so balance the oxygen atoms by putting a coefficient of 5 in front of the O₂ molecule.
Therefore, the correct whole number coefficient for propane, C3H8, is 1.
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Hi can someone help me with this homework
We must melt about 3.8 kg of brass A, 4.1 kg of brass B, and 6.5 kg of brass C to obtain about 14.5 kg of the desired alloy
How do we calculate?we can set up a system of equations based on the conservation of mass and the desired composition:
0.533x + 0.247y + 0.220z = 14.5 (desired composition of copper, zinc, and nickel)
The given information includes:
Brass A: 41% copper, 23% zinc, 36% nickel
Brass B: 54% copper, 23% zinc, 23% nickel
Brass C: 56% copper, 26% zinc, 18% nickel
Using this information, we can write the following equations:
0.41x + 0.54y + 0.56z = 0.533(x + y + z) (copper)
0.23x + 0.23y + 0.26z = 0.247(x + y + z) (zinc)
0.36x + 0.23y + 0.18z = 0.220(x + y + z) (nickel)
Simplifying each equation, we get:
0.067x - 0.027y - 0.023z = 0 (copper)
-0.017x + 0.017y + 0.003z = 0 (zinc)
-0.020x - 0.027y + 0.038z = 0 (nickel)
We can solve the equations using substitution method or elimination method and our values will be:
x = 3.8462
y = 4.1077
z = 6.5461
In conclusion, we need to melt about 3.8 kg of brass A, 4.1 kg of brass B, and 6.5 kg of brass C to obtain about 14.5 kg of the desired alloy.
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Can someone help me out with the question
A teacher showed this animal to studenst on a field trip
If a teacher showed an animal to students on a field trip. The tool will allow the students to best see the animal up close is the hand lens.
Option D is correct.
What is a Hand lens?A hand lens is known as a magnifying glass which is a convex lens that is used to produce a magnified image of an object. The lens is usually mounted in a frame with a handle.
A hand lens has two essential properties which are its focal length and its diameter.
The students will therefore require a hand lens to look up the animal close.
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#complete question:
A teacher showed this animal to students on a field trip. Which tool will allow the students to best see the animal up close? O A Tape measure O B Graduated cylinder O c. Notebook O D. Hand lens
6. Who stated that matter is not composed of particles
After careful consideration your answer is...
Leucippus and Democritus
*Hope I helped*
~Alanna~
Answer:
The first theories of matter were put forward by Empedocles in 450 BC, he proposed that all matter was composed of four elements - Earth, air, fire and water. Later, Leucippus and Democritus suggested matter was made up of tiny indestructible particles continuously moving in empty space.
Explanation:
Before a new medicine is approved, scientists study the effects the medicine has on different parts of the body. Often, a medicine is tested on mice before it is tested on humans. All the cells in the illustration below came from the same mouse.
Four images of unique looking cells
If all of these cells are mouse cells, why do they look so different from each other?
A. Cells change shape as they get older.
B. Different cells specialize in different functions.
C. Each kind of cell is from a different organ system.
D. Different-shaped cells came from different ancestors.
Answer:
different cell specialized in different function
Different cells specialize in different functions but they look so different from each other.
What is a cell?The basic and structural component of life is the cell. Cell biology is the study of cells, including their fundamental makeup and each organelle's functions. Cells were initially found by a biologist, Robert Hooke.
Cells comprise all living things. They could consist of several cells or just one (unicellular) (multicellular). The tiniest known cells are mycoplasmas. The foundation of all living things is cells. They give the body structure and transform the food's nutrients into energy.
Complex cells have many parts that each serve a different purpose within an organism. Similar to constructing bricks, they come in a variety of sizes and shapes. Our body is made up of various types of cells.
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A piece of metal is heated to 250 degrees then placed in a bucket of water with an initial temperature of 15 degrees. After 10 minutes, the system reaches a point of thermal equilibrium. The water is now 22 degrees. Which of the following is the most likely temperature of the piece of metal?
Answer: 22 degrees
Explanation:
Most of the information in this question is put there to throw you off- the only important piece of information here is the final temperature of the water.
In a system of say 2, like in this example, whichever object has more energy in the form of heat will transfer that heat to the object with lesser heat if there is an available path to transfer heat between them. Once the two objects are at the same temperature, however, heat can not be transferred from one to another since neither object has more heat than the other to transfer- this is thermal equilibrium.
This question tells us that the system is at thermal equilibrium- when both objects are at the same temperature. Given the temperature of one object, the water, we then know the other object, the metal is the same temperature.
Global warming is an increase in the Earth's average surface air temperature. Which of the following describes how weather conditions on Earth will most likely change as a result of global warming?
A.
All regions on Earth will experience severe droughts and wildfires that will destroy the Earth's surface.
B.
Some areas on Earth will experience an increase in rainfall, whereas other areas will experience severe droughts.
C.
All regions on Earth will become increasingly cooler, causing oceans and lakes to completely freeze over.
D.
Weather conditions on Earth will become static and no longer experience daily change.
Answer:THE ANSWER IS B
Explanation:
DO NOT TRUST THE OPTHER GUY I JUST DID IT AND GOT IT WRONG BECAUSE OF HIm
The global warming causes severe impacts on plants, animals and all living organisms. Some areas on Earth will experience an increase in rainfall, whereas other areas will experience severe droughts .The correct option is B.
What is global warming?The phenomenon in which there is a gradual increase in the temperature near earth's surface due to the green house effect of the gases like carbon dioxide, methane, etc. is known as global warming.
The green house effect is defined as a process in which the radiations from the sun are absorbed by the green house gases and not reflected back into space. This will depletes the ozone layer.
The major cause of global warming is the incredible increase in the temperature which melts glaciers, increases evaporation and there by causes heavy rainfall. The climatic conditions are changed due to this. There are droughts at some places and floods at some.
Thus the correct option is B.
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Amelia makes a Venn diagram to compare the advantages and disadvantages of asexual reproduction and sexual reproduction.
Which label belongs in the region marked X?
Answer:
what's marked in x......................
Answer:
answer is A. Less competition for resources
Explanation:
hope this helps!
hich of the following is a typical cost associated with renting?
a.
closing costs
b.
down payment
c.
property tax
d.
security deposit
Answer:
D
Explanation:
The other three are related to
a. selling a home
b. buying a home
c. owning a home
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