Answer:
Explanation:
A mixture of a weak acid and its conjugate base (or a mixture of a weak base and its conjugate acid) is called a buffer solution, or a buffer. Buffer solutions resist a change in pH when small amounts of a strong acid or a strong base are added (Figure 1). A solution of acetic acid and sodium acetate (CH3COOH + CH3COONa) is an example of a buffer that consists of a weak acid and its salt. An example of a buffer that consists of a weak base and its salt is a solution of ammonia and ammonium chloride (NH3(aq) + NH4Cl(aq)).
The pH of the resulting buffer solution is 6.60.
How to calculate pH of acidic buffer solution?pH of acidic buffer solution is calculated by Henderson equation which is,
pH =pK[tex]_a[/tex] +log[salt]/log[acid]
As the buffer is diluted the concentration is reduced to half, that is
[acid]=0.075 M
[salt]=0.02 M pK[tex]_a[/tex]=4.74
substituting these values in Henderson's equation for acid buffers,
pH=4.74+log[0.075]/[0.02]
=6.6071
Thus, the pH of resulting buffer solution is 6.6071.
Acid buffers consist of a solution of weak acid and its salt.A commonly used acid buffer is prepared by mixing acetic acid and sodium acetate.
Henderson equation is used to calculate pH of buffer solution and ratio of salt to acid to prepare acid solution. pK[tex]_a[/tex] for acid buffers is constant.
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Use the table to identify the phase and phase changes of the elements under the given conditions. Write the name of the substance, phase, or phase change.
When the temperature in a room increases from
25°C to 33°C,
changes from a solid
to a liquid.
In a lab, methane and nitrogen are cooled from
-170°C to -200°C. The methane freezes and the
nitrogen
.
When gold is heated to 2,856°C it changes from a liquid to a
.
Answer: gallium, condenses, gas
Explanation: took assignment on edge
Answer: gallium, condenses, gas
Explanation: took assignment on edge
A student estimated a mass to be 275 g but upon carefully measuring it found the actual mass to be 260 g. what is the percent error in the estimation?
Answer:
5.77% Error.
Explanation:
Given an experimental value of 275 g , and a theoretical value of 260 g, the percent error can be found using the equation:
[tex]\% \: error \: = \frac{ |theoretical \: value \: - \: experimental \: value | }{theoretical \: value} \times 100[/tex]
% Error = ( | 260 - 275 | / 260 ) × 100 = ( | - 15 | / 260 ) × 100 = ( 15 / 260 ) × 100 = 1500/260 = 300 / 52 = 5.769230769230.. ≈ 5.77%
A researcher wants to refine an investigation to determine the effectiveness of an enzyme at various temperatures. Which of the following would best help the researcher determine how well the enzyme is working? Question 20 options: The researcher should measure the difference in temperature during the reaction. The researcher should measure the difference in the amount of product at the beginning of the reaction. The researcher should measure the difference in the amount of enzyme remaining after the reaction. The researcher should measure the difference in the amount of product at the end of the reaction.
Answer:
The researcher should measure the difference in the amount of product at the end of the reaction.
Explanation:
Enzymes are defined as the protiens that are responsible for increasing the rate of reaction.
With the increase in temperature, the enzyme activity increases and so the rate of reaction increases. It means at lower temperature the rate of reaction decreases and the amount of product also decreases.
So, to determine the effectiveness of an enzyme at various temperatures, the difference in the amount of the product at the end of reaction should be measured.
Hence, the correct answer is "D".
Which of the following is a property of a pure substance?
It consists of different types of compounds.
It may have substances in different states of matter.
The ratio of the particles that make it up is fixed.
Its components can be separated by employing physical methods.
Answer:
The ratio of the particles that make it up is fixed
Explanation:
18. The density of rubbing alcohol is .789 g/ml. What is the mass of rubbing alcohol in a 500-ml bottle of rubbing alcohol?
Answer:
The number of milliliters of isopropyl alcohol that are in a 400 ml bottle of this solution is 280 Ml
Explanation:
% V/V = volume of solute/ volume of solution x 100
Let the volume of solute be = y ml
the volume of solution = 400 ml
convert 70% to fraction = 70/100
by substituting the value in the equation
= y ml/ 400 ml = 70/100
by cross multiplication
100y =400 x70
100y= 28000
y= 280 ml
What does the mass of an object depend on?
A. Force of gravity
B. Temperature of the object
C. Time taken of an event to occur
C. Amount of matter that makes up the object
Answer:
D or the 4th one
Explanation:
mass is literally the measure of matter in an object which is essentially the weight or how much stuff there is.
Answer:
C:)
Explanation:
what is the molar mass of CO^2
Answer:
44.01 g/mol
There you go, hope it helped!!!!!
Variable definition
Answer: is factor that change in a controlled experiment
Explanation:
. The freezing point of an aqueous solution containing a nonelectrolyte solute is – 2.79 °C. What is the boiling point of this solution?
Answer:
Boiling point of the solution is 100.78°C
Explanation:
This is about colligative properties.
First of all, we need to calculate molality from the freezing point depression.
ΔT = Kf . m . i
As the solute is nonelectrolyte, i = 1
0°C - (-2.79°C) = 1.86 °C/m . m . 1
2.79°C / 1.86 m/°C = 1.5 m
Now, we go to the boiling point elevation
ΔT = Kb . m . i
Final T° - 100°C = 0.52 °C/m . 1.5m . 1
Final T° = 0.52 °C/m . 1.5m . 1 + 100°C → 100.78°C
Soda has a density pf 1.05 g/mL. What is the mass of 2000 mL of soda?
A. 2100 g
B. 1905 g
C. 0.0005259
D. 2005 g
Answer:
The answer is option AExplanation:
The mass of a substance when given the density and volume can be found by using the formula
mass = Density × volumeFrom the question
volume = 2000 mL
density = 1.05 g/mL
The mass of soda is
mass = 2000 × 1.05
We have the final answer as
2100 gHope this helps you
is helium gas a mixture or pure substance
Which statement describes the general process of diffusion?
Molecules move from inside of the cell to outside of the cell.
Molecules start out unevenly distributed and end up evenly distributed.
Molecules start out evenly distributed and end up unevenly distributed.
Molecules move from outside of the cell to inside of the cell.
Answer:
Molecules start out unevenly distributed and end up evenly distributed.
Explanation:
Diffusion is the process by which molecules of a substance move from a region of higher concentration to a region of lower concentration until equilibrium is attained.
Molecules start out unevenly distributed and end up evenly distributed in a particular medium. Diffusion occurs due to the particulate nature of matter. When the particles that make up a substance are concentrated at a point, the collide more often with one another causing each molecule to spread out in order to occupy all the available space.
Diffusion occurs in gases, liquids and solids but occurs fastest in gases. Diffusion can be observed for example, in the spread of the smell of a dead rat from one point in a room to every part of the room.
Answer:
B
Explanation:
:D
What is an experimental error
Answer:
Explanation: errors in judgment of an observer when reading the scale of a measuring device to the smallest division. 2. Environmental. For example, unpredictable fluctuations in line voltage, temperature, or mechanical vibrations of equipment.
Why does the flow of science just keep going
Answer:
The Flow of science keeps going because not everything is fully discovered yet. New things are discovered everyday and are also made better as well.
Explanation:
Which image below shows the correct way to convert 0.828 kilometers to meters
Explain the rationale and what happens to the units.
Answer:
A
Explanation:
Because you need to multiply the length value by 1000
Name 2 gram negative bacteria often found in contaminated food
You are concerned about the rate of death in catfish your aquaculture operation in tanks that have a high amount of algae growth. You collect some of the algae and send it to the university to have it identified. You find that it is a blue-green alga called Anabaena. Anabaena is known to be toxic to fish. You design an experiment to test how much of the algae the fish can stand before they die. You obtain 6 large aquariums (all the same size) and fill them with water taken from a healthy catfish pond at your operation. You put each aquarium on the same bench in the laboratory, where the light and temperature values are identical. You let the water stand for one day before starting the experiment. In aquarium 1, you add 2 grams of algae and no fish. In aquarium 2, you add 20 small catfish and no algae. Aquarium 3 gets 20 catfish and 2 grams of algae, #4 gets 20 catfish and 4 grams of algae, #5 gets 20 catfish and 8 grams of algae, and aquarium #6 gets 20 catfish and 16 grams of algae. The aeration rate of each aquarium is identical. You make two observations at the same time each day for two weeks. You keep track of the numbers of fish in each tank that die. What is the problem? What is your hypothesis? What is the independent variable? What is the dependent variable?
Answer:
Problem: How does the amount of algae (anabaena) affect or cause the number/rate of catfish death
Hypothesis: IF there is a high amount of algae growth, THEN the rate at which catfishes die increases.
Independent variable: Amount in grams of algae
Dependent variable: Number of catfishes that die.
Explanation:
A scientific experiment starts with an observed problem or a question which can be tested. In this experiment, the rate of death of catfish in an aquaculture due to the high amount of algae (anabaena) growth is observed, hence, it is the problem. It will be asked as a question: HOW DOES THE AMOUNT OF ALGAE IN A TANK CAUSE THE RATE AT WHICH CATFISHES DIE.
Formualting an Hypothesis is the next step of a scientific method. Hypothesis is a testable explantation or suggested solution to the observed problem or asked question. A hypothesis of this experiment can be: IF THERE IS A HIGH AMOUNT OF ALGAE GROWTH, THEN THE RATE AT WHICH CATFISH DIE INCREASES.
Next is to test the hypothesis by conducting an experiment. In an experiment, the independent variable is the variable that the experimenter changes or manipulates in order to bring about a response. In this experiment, the independent variable is the AMOUNT IN GRAMS OF ALGAE ADDED TO EACH AQUARIUM.
On the other hand, the dependent variable is the variable being tested or measured in an experiment. In this experiment, the dependent variable is the NUMBER OF CATFISH THAT DIE.
The temperature of a container of oxygen gas is increased from 149 k to 298 k which of the following statement is true
Answer:
______is used in production of hard disk.
Explanation:
how many seconds are there in 45 days?
Answer:3,888,000seconds
Explanation:
60secx60minsx24 hoursx45days=3,888,000
What is the speed of an object that moves 100 meters in 5 seconds?
Answer:
speed= distance/time
= 100/5=20mph
Which of these limiting factors is MOST likely to affect low-growing plants in a tropical forest? Group of answer choices air water shelter sunlight
Answer:
air, water, sunlight
Explanation:
A limiting factor may be defined as a environmental condition or a resource that can limit the plant growth as well as distribution or the abundance of an organism or its population within the ecosystem. The ability of any plant species to grow and spread throughout any geographic area is the direct result of the adaption to its biotic and abiotic components of that region.
Some of the factor that affect the plant growth are : sunlight, air, proper temperature, moisture, nutrients, wind,etc.
The lack of the any one of the above essential component will determine the health of the plant.
5.
2. Which of the following statements
indicates that a new substance is
forming?
a. A liquid is changing to a solid
b. Metal is melting
C. A substance is fizzing or
bubbling
d. A liquid evaporating to a gas
Answer:
A. A liquid is changing to a solid
hope this helps
what is the function of spines ?
Answer:
The spine is also designed to protect your spinal cord. The spinal cord is a column of nerves that connects your brain with the rest of your body, allowing you to control your movements. Without a spinal cord, you could not move any part of your body, and your organs could not function.
A certain ore is 20.7% nickel by mass. How many kilograms of this ore would you need to dig up to have 70.0 g of nickel?
Answer:
0.3382 kg
Explanation:
From the illustration:
100g of the ore would contain 20.7 g of nickel by mass. In order to obtain 70.0 g of nickel, the amount of the ore needed would be:
100 x 70.0/20.7 = 338.16 g
According to conversion units:
1 g = 0.001 kg
Hence,
338.16 g = 338.16 x 0.001 = 0.3382 kg
Therefore, 0.3382 kg of the ore would be required in order to obtain 70.0 g of nickel.
Amount of core in Kilogram is 0.338 kg (Approx.)
Given that;Percentage in every ore = 20.7%
Amount of nickel = 70 gram
Find:Amount of core in Kilogram
Computation:Amount of core in Kilogram = Amount of nickel / Percentage in every ore
Amount of core in Kilogram = 70 / 20.7%
Amount of core in Kilogram = 70 / 0.207
Amount of core in Kilogram = 338.16 gram
Amount of core in Kilogram = 0.338 kg (Approx.)
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Convert 78.9 kJ into calories
(can you also explain how pls, ty <3)
Answer:.1 kJ = 1000 J and 1J=0.24cal
----->78.9kJ=1000x78.9x0.24=18936cal
Explanation:
This is the unit regulated by the scientific community and they follow the formula that they prove
Describe how the proton, electron and neutron were experimentally discovered.
1. Write the name meaning
a. 0.1 gram
b. 0.01 meter
c. 0.000001 liter
e. 1000 000 grams.
L. 10 meters
Answer:
A.. 0.1 gram this means 0.0001kg of the object in SI unit
b. 0.01 meter this means 1 / 10 of 1 meter of the measurement
c. 0.000001 liter this means 1/10000 of the quality of liquid in SI unit
e. 1000 000 grams.this means 1000kg of the object in IS unit
L. 10 meters this means 10 times one meter of the measurement in SI unit
Mixing two clear liquids results in the formation of a whit solid. Is this a physical or chemical change?
Answer:
Chemical Change
Explanation:
It became white and became solid which makes it a chemical change.
Choose the nonmetallic elements from the list. Check all that apply yttrium: oxygen: boron: polonium: argon: gallium: carbon:
Answer:
Oxygen, Argon, and Carbon.
Explanation:
Just finished the assignment.
Oxygen ,boron and carbon are the non metallic elements. Thus, options B, C, and G are correct.
What are non metallic elements?Non-metallic elements are the elements which easily form negative ions by accepting or gaining electrons and which do not have complete electronic configuration like rare gas. Non metals have high ionization energies and electronegativity.
They are generally poor conductors of heat and electricity. Solid non metals are generally brittle, with little or no metallic lustre.
Most non metals have the ability to gain electrons easily. Non metals display a wide range of chemical properties and reactivities.
In above except oxygen, boron and carbon all other elements are metallic in character that possess metallic property. Thus, options B, C, and G are correct.
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My favorite student weighs in at 125 pounds. How many
kilograms do they weigh?
Answer:
56.69905
Explanation:
The conversion factor from pounds to kilograms is 0.45359237, which means that 1 pound is equal to 0.45359237 kilograms.