Answer:
An acid with Kg = 1.3 times 10-10.
Explanation:
The formula for pH of a buffer solution is as follows
pH = pKa + log [ A⁻ ] / [ HA ]
HA is acid concentration and A⁻ is concentration of conjugate base .
Generally the the second term is very small so neglecting this figure
pH = pKa
9.8 = pKa
If Ka = 10⁻¹⁰ x 1.3
pKa = - log ( 10⁻¹⁰ x 1.3 )
= 10 - log 1.3
= 9.8 approx .
Hence option F is correct .
Identify all of the predominant forms of energy produced when each process occurs. Some processes may produce only one form of energy, whereas others may produce more than one form of energy. An electric light bulb is turned on. A log is burned in a fireplace. Answer Bank mechanical thermal cheat) electrical radiant light) chemical A green plant grows. A bicycle is pedaled. A flashlight is turned on.
Answer:
Explanation:
An electric light bulb is turned on. Thermal heat , radiant light
A log is burned in a fireplace . Thermal heat , radiant light
A green plant grows Chemical
A bicycle is pedaled Mechanical ,
A flashlight is turned on. radiant light
An element has four naturally occurring isotopes with the masses and natural abundances given here. Isotope Mass (amu) Abundance (%) 1 89.90470 52.93 2 90.90565 11.54 3 91.90504 17.65 4 93.90632 17.88 Find the atomic mass of the element. Express your answer to four significant figures and include the appropriate units.
Following are the calculation to the atomic mass:
Given:
Please find the attached file.
To find:
atomic mass=?
Solution:
Following are the calculation to the atomic mass:
[tex]\to 89.90470\times (0.5293)+90.90565\times (0.1154)+91.90504\times (0.1765)+93.90632\times (0.1788)\\\\\to 47.58655771 +10.49051201 +16.22123956+16.790450016\\\\\to 91.0887593\approx 91.0887\ amu \\\\[/tex]
Therefore, the final answer is "91.0887".
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Cell theory states:
A. All living things need glucose to survive
B. All living things Must have a nucleus surrounding DNA
C. All living things are composed of cells
D. The basic unit of life is a cell
Group of answer choices
C & D
A & D
B, C & D
B only
Answer:
C&D all living things are composed of cells
The basic unit of life is a cell
100 POINTS & BRAINLIEST !!!! PLEASE HELP
Answer:
independent: type of liquid
dependent: growth of plant
control: time
constant: time
constant: time
hypothesis: If I water the plant with water, it will grow the most because water is the liquid that sustains life on earth.
Explanation:
Which of the following statements best explains the observation that hydrogen fluoride has the highest boiling point of all the hydrogen halides?a. The fluorine in HF is the smallest atom for all of the halogens. b. Fluorine is the most electronegative of the atoms. c. HF can participate in hydrogen bonding. d. HF is very reactive and can react and dissolve glass e. HF is a weak acid, and doesn
Answer:
c. HF can participate in hydrogen bonding.
Explanation:
The boiling points of substances often reflect the strength of the intermolecular forces operating among the molecules.
If it takes more energy to separate molecules of HF than of the rest of the hydrogen halides because HF molecules are held together by stronger intermolecular forces, then the boiling point of HF will be higher than that of all the hydrogen halides.
A particularly strong type of intermolecular attraction is called the hydrogen bond, which is a special type of dipole-dipole interaction between the hydrogen atom in a polar bond, such as N-H, O-H, or F-H, and an electronegative O, N, or F atom.
How can you use the number of electrons in an aluminum atom to determine how many protons and neutrons are in its nucleus?
Answer:
You use the number of electrons in an aluminum atom to determine how many protons are in its nucleus because the atomic number of aluminum, 13, tells you how many electrons and protons they are. Then you can the number of neutrons by subtract it's atomic number by its mass, 27, which will result in the number of neutrons, 14.
Explanation:
The atomic number of aluminum is 13 and mass number of aluminum is 27. This helps us to tell us how many protons, electrons and neutrons are there in its nucleus.
What is atomic number?The atomic number of a chemical element is defined as the charge number of an atomic nuclei.
The mass number of an atom tells us the number of protons and neutrons are there in an atoms.
The number of electron surrounding the nucleus is equal to number of protons present in the nucleus. Hence there is 13 electrons and 13 protons in the nucleus.
Now we can calculate number of neutrons present in the nucleus.
Mass number = number of protons + number of neutrons
Number of neutrons = mass number - number of protons
= 27 - 13 = 14
So number of neutrons is 14 , and number of protons is 13.
Thus, atomic number of aluminum is 13 and mass number of aluminum is 27. This helps us to tell us how many protons, electrons and neutrons are there in its nucleus.
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An electrically neutral atom bears what trait?
A) It contains protons in its nucleus.
B) It contains the same number of protons and neutrons.
C) It contains the same number of electrons and protons.
D) It contains electrons in its electron shells.
C) It contains the same number of electrons and protons.
can someone help me please ??!!
Answer:
0.617
Explanation:
The experimental value is the average of all the values recorded:
(2.65 + 2.73 + 2.77)/3 = 2.72
Then use the equation:
(2.72 - 2.7)/ 2.7 x 100 = 0.617
Now balance the chemical reaction by providing the correct coefficients:
Answer: 2 Al + 3 Cl₂ → 2 AlCl₃
Explanation:
To balance equations, you want to have the same amount of each element. We know 2 Al + 3 Cl₂ → 2 AlCl₃ is the balanced equation because there are equal amounts of each element on both sides. There are 2 Al and 6 Cl.
Please have your periodic table of elements. An atom has 8 protons and 9 neutrons what is the chemical symbol for this isotope? Question 9 options: Flourine F-17 Oxygen O-17
Answer:
A. is the answer i think
Explanation:
Which of the following is not one of the four groups of organic compounds
The following that is not one of the four groups of organic compounds is a monosaccharide. The correct option is D.
What are organic compounds?Any of a vast group of chemical compounds known as organic compounds contain one or more carbon atoms that are covalently connected to atoms. Organic compounds are made up of carbon and hydrogen, and oxygen.
Carbohydrates, lipids, proteins, nucleic acids, and nucleotides are organic compounds. Due to their presence of both carbon and hydrogen, these substances are referred to as organic.
Monosaccharides are the single unit of carbohydrates. They join to form polymers of carbohydrates. They are glucose, fructose, etc. It is a single unit of carbohydrates. It is not one of the organic compound.
Thus, the correct option is D) monosaccharides.
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The question is incomplete. Your most probably complete question is given below:
A) carbohydrates D) monosaccharides B) lipids E) proteins C) nucleic acids
An unknown substance is measured. It has a mass of 0.221 g and a volume of 2.25 mL. What is its density?
Answer:
d ≈ 0.098 g/mL
Explanation:
The density of a substance can be found by dividing the mass by the volume.
d=m/v
The mass of the substance is 0.221 grams and the volume is 2.25 milliliters.
m= 0.221 g
v= 2.25 mL
Substitute the values into the formula.
d= 0.221 g / 2.25 mL
Divide
d= 0.098222222 g/mL
Let’s round to the nearest thousandth. The 2 in the ten thousandths tells us to keep the 8 in the thousandth place.
d ≈ 0.098 g/mL
The density of the substance is about 0.098 grams per milliliter.
Answer:
Explanation:5.70
Magnesium exists in nature as three stable isotopes. Suppose you determine that 9.87 moles of natural magnesium are required if you wish to isolate 1.00 mole of pure Mg-25 (24.9858 amu). The most abundant isotope is Mg-24 with a mass of 23.9850 amu. Determine how many grams of the third isotope, Mg-26 (25.9826 amu), can be isolated from the 9.87 mole sample of natural magnesium.
Answer: 28.2 g of ²⁶Mg can be isolated from the 9.87 mole sample of natural magnesium
Explanation:
we know that natural abundance of ²⁶Mg is 11.01 %
therefore moles of ²⁶Mg isolated from 9.87 mole sample of natural magnesium will be :
( 11.01 x 9.87 mol) / 100 = 1.09 mol
so
mass of ²⁶Mg = mol x molar mass
⇒ 1.09 mol x 25.9826 g/mol
= 28.2 g
Therefore 28.2 g of ²⁶Mg can be isolated from the 9.87 mole sample of natural magnesium
Which of the following compounds is neither an acid or a base? (select as many)
Answer:
Sodium nitrate and CH4
Explanation:
Acids have an "H" at the start and bases have a hydroxide (OH)
Which of the following is a property of a mixture?
Answer:
A mixture has 2 or more substances that are physically combined
Explanation:
Examples:
-Dirt and water (Mud)
-Water and salt (Sea water)
-Smoke and fog (Smog)
Please Help with this!!!!!
Answer:
a) 4.69
Explanation:
v=mp
m=10.55
p=2.25
v=10.55/2.25=4.69
What is heat transferred from movement of fluids in a circular motion called
Answer: it's known as heat transfer
Explanation: Heat always moves from a warmer substance to a cooler substance. For example, holding an ice cube will make your hand begin to feel cold in a few seconds. But is the coldness in the ice cube moving to your hand? No! Since cold is the absence of heat, it’s the heat in your hand that moves to the ice cube. This is one of the ways that heat is transferred.
According to the concept of thermal energy, heat transfer in a circular motion is called as convection.
What is thermal energy?
Thermal energy is defined as a type of energy which is contained within a system which is responsible for temperature rise.Heat is a type of thermal energy.It is concerned with the first law of thermodynamics.
Thermal energy arises from friction and drag.It includes the internal energy or enthalpy of a body of matter and radiation.It is related to internal energy and heat .It arises when a substance whose molecules or atoms are vibrating faster.
These vibrating molecules and atoms collide and as a result of which heat is generated in a substance , more the collision of particles , higher is the thermal energy.There are three types of thermal energy.
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One possible source of error in this experiment is not completely drying the NaCl. Effect of Percent yield ? And other questions
Answer:
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12.9 Theoretical Yield and Percent Yield
FlexBooks® 2.0 > CK-12 Chemistry For High School > Theoretical Yield and Percent Yield
It is best to have high yields for chemical reactions
Can we save some money?
The world of pharmaceutical production is an expensive one. Many drugs have several steps in their synthesis and use costly chemicals. A great deal of research takes place to develop better ways to make drugs faster and more efficiently. Studying how much of a compound is produced in any given reaction is an important part of cost control.
Percent Yield
Chemical reactions in the real world don’t always go exactly as planned on paper. In the course of an experiment, many things will contribute to the formation of less product than would be predicted. Besides spills and other experimental errors, there are usually losses due to an incomplete reaction, undesirable side reactions, etc. Chemists need a measurement that indicates how successful a reaction has been. This measurement is called the percent yield.
To compute the percent yield, it is first necessary to determine how much of the product should be formed based on stoichiometry. This is called the theoretical yield, the maximum amount of product that could be formed from the given amounts of reactants. The actual yield is the amount of product that is actually formed when the reaction is carried out in the laboratory. The percent yield is the ratio of the actual yield to the theoretical yield, expressed as a percentage.
Percent yield is very important in the manufacture of products. Much time and money is spent improving the percent yield for chemical production. When complex chemicals are synthesized by many different reactions, one step with a low percent yield can quickly cause a large waste of reactants and unnecessary expense.
Typically, percent yields are understandably less than 100% because of the reasons indicated earlier. However, percent yields greater than 100% are possible if the measured product of the reaction contains impurities that cause its mass to be greater than it actually would be if the product was pure. When a chemist synthesizes a desired chemical, he or she is always careful to purify the products of the reaction.
Sample Problem: Calculating the Theoretical Yield and the Percent Yield
Potassium chlorate decomposes upon slight heating in the presence of a catalyst according to the reaction below:
In a certain experiment, 40.0 g KClO3 is heated until it completely decomposes. What is the theoretical yield of oxygen gas? The experiment is performed and the oxygen gas is collected and its mass is found to be 14.9 g. What is the percent yield for the reaction?
First, we will calculate the theoretical yield based on the stoichiometry.
Step 1: List the known quantities and plan the problem.
Known
given: mass of KClO3 = 40.0 g
molar mass KClO3 = 122.55 g/mol
molar mass O2 = 32.00 g/mol
Unknown
theoretical yield O2 = ? g
Apply stoichiometry to convert from the mass of a reactant to the mass of a product:
Step 2: Solve.
The theoretical yield of O2 is 15.7 g.
Step 3: Think about your result.
The mass of oxygen gas must be less than the 40.0 g of potassium chlorate that was decomposed.
Now, we use the actual yield and the theoretical yield to calculate the percent yield.
Step 1: List the known quantities and plan the problem.
Known
Actual yield = 14.9 g
Theoretical yield = 15.7 g (from Part 12.11A)
Unknown
Percent yield = ? %
Use the percent yield equation above.
Step 2: Solve.
Step 3: Think about your result.
Since the actual yield is slightly less than the theoretical yield, the percent yield is just under 100%.
Summary
Theoretical yield is calculated based on the stoichiometry of the chemical equation.
The actual yield is experimentally determined.
The percent yield is determined by calculating the ratio of actual yield/theoretical yield.
Review
What do we need in order to calculate theoretical yield?
If I spill some of the product before I weigh it, how will that affect the actual yield?
How will spilling some of the product affect the percent yield?
I make a product and weigh it before it is dry. How will that affect the actual yield?
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Explanation:
If you lived in Flint, Michigan why would it be important for you to understand chemistry
Answer:
If I lived in Flint, Michigan, it would be important for me to understand chemistry because of the high contamination levels of water in the city, in order to know how to help to solve this issue and to avoid any potential harm to my health.
There is an ongoing drinking water issue since 2014 in Flint, Michigan. In April 2014, the Flint authorities changed the source of water from the Detroit Water and Sewage Department, which takes it from Lake Huron and the Detroit River, to the Flint River for cost-effective reasons. This led to a series of water quality problems culminating in the presence of lead, creating a serious threat to public health.
Are the bonds that chlorine forms with sodium (to form NaCl) and with carbon (to form CCl4) the same in both compounds?
Answer:
Organic chemistry is very important to know the strength and forms of the compounds.
Explanation:
There are two extreme bonding that is ionic and covalent. There are some ionic bonds that contains the covalent bonding. Some of ionic bond are partially covalent and some covalent bond are ionic. Polar covalent have the extreme type of bonding.
Most of the carbon compound are bonded covalently. But these are partial ionic too. Polarity is defined as the measurement of the separation of the charges of the compounds at both the ends.
Ionic compounds allow synthesis in organic compound. Covalent bonds are differently important for carbon molecules bonding.
Thus the bonds that chlorine forms with sodium is different and when form with carbon then compounds will be different
Convert 45 kL to mL (must show work)
Answer:
1 kiloliter = 1,000,000 milliliters
45 × 1,000,000
45 KL = 45,000,000 ML
The specific heat of water is 4.184 J/ g°C, the specific heat of wood is 1.760 J/g°C, and the specific heat of coal is 1.26 J/g°C. Which of these materials requires the most heat to raise its temperature by one degree Celsius?
A. All materials need the same amount of energy.
B. Wood
C. Coal
D. Water
Answer:
D. Water
Explanation:
Specific heat is defined as the amount of heat you need to add to a substance per unit of mass to increase its temperature in 1°C.
That means if you have the same mass of substances, the one with the higherst specific heat is the one that requires the most amount of heat to increase its temperature by one degree Celsius.
As you can see, water is the material with the highest specific heat doing the material that requires the most heat.
Right answer:
D. WaterAnswer: D
Explanation: I took the test
ILL GIVE YOU BRAINLIST !!
Which are the quantitative data in the example above? Explain.
Answer:
helicona
throated carib
eulampis jugularis
Answer:
The percentages
Explanation:
Quantitative data are numbers, while qualitative data are characteristics. So I think that the numbers are your answer.
Hope that helps!
ILL GIVE BRAINLIEST ⏳⏳⏳⏳⏳⌛◑﹏◐ Lorenzo is making a prediction. “I learned that nonmetals increase in reactivity when moving from left to right. So I predict that xenon will be more reactive than iodine.” Is Lorenzo correct? If so, why? If not, explain his error.
Answer:
Answer is no because,
Explanation:
Iodine is LESS REACTIVE than the elements above it in group 17 (fluorine, chlorine and bromine) it still forms compounds with many other elements. Although iodine is a non-metal, it displays some METALLIC properties. Xenon is one of the inert or noble gases and is odorless, colorless, tasteless and chemically NON REACTIVE
PLEASE MARK BRAINLIEST
Write a balanced equation for the neutralization of hydrochloric acid by barium hydroxide. Use the smallest possible integer coefficients.
Answer:
2HCl + Ba(OH)2 = BaCl2 + 2H2O
Explanation:
To solve such this we must know the concept of neutralization reactions. Therefore, the balanced equation for the neutralization of hydrochloric acid by barium hydroxide is 2HCl + Ba(OH)[tex]_2[/tex] [tex]\rightarrow[/tex] BaCl[tex]_2[/tex] + 2H[tex]_2[/tex]O.
What is chemical reaction?Chemical reaction is a process in which two or more than two molecules collide in right orientation and energy to form a new chemical compound. The mass of the overall reaction should be conserved.
Neutralization is an acid-base reaction in which an acid reacts with just a base to produce salt and water. The pH of a neutralizing solution is determined by the acid strength and concentrations of the reactants. The balanced equation for neutralization of hydrochloric acid by barium hydroxide can be written as
2HCl + Ba(OH)[tex]_2[/tex] [tex]\rightarrow[/tex] BaCl[tex]_2[/tex] + 2H[tex]_2[/tex]O
Therefore, the balanced equation for the neutralization of hydrochloric acid by barium hydroxide is 2HCl + Ba(OH)[tex]_2[/tex] [tex]\rightarrow[/tex] BaCl[tex]_2[/tex] + 2H[tex]_2[/tex]O.
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How many moles of CO2 are produced
if 6 moles of O2 are used?
C6H12O6 + 602 + 6CO2 + 6H2O
Answer:
6 moles
Explanation:
Forst of all arrange the equation, it isn't in the right order and I suppose the equation is of aerobic respiration:
That is :
C6H12O6 + 6O2 ---------> 6CO2 + 6H20 + 2830kJ (energy)
Then use the ratio which can be seen by the balancing:
02 : CO2
6: 6
The ratio clearly shows how much moles of CO2 are produced; 6 moles
The term mole concept is used here to determine the moles of carbon dioxide produced. The moles of CO₂ produced from the given reaction is 6.
What is a mole?One mole of a substance is defined as that quantity of it which contains as many entities as there are atoms exactly in 12 g of carbon - 12. The formula used to calculate the number of moles is:
Number of moles = Given mass / Molar mass
The balanced equation for the oxidation reaction of glucose is given as:
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + E
In a balanced equation the number of atoms of reactants and products on both sides of the equation are equal. The number of 'C', 'H' and 'O' atoms on both sides of the equation are equal.
Here the number of moles of CO₂ produced from 6 moles of oxygen is 6.
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Hydrogen reacts with nitrogen monoxide to form dinitrogen monoxide (aughing gas) according to the equation: H2 (g) + 2NO(g) → N2O(g) + H2O(g)Based on the following data: Trail 1 Trail 2 Trail 3H2 (M) 0.30 0.60 0.60NO (M) 0.35 0.35 0.70Rate (M*s) 2.835 x 10^-3 1.134 x 10^-2 2.268 x 10^-2Required:a. What is the order with respect to H2? b. What is the order with respect to NO? c. What is the rate equation for this reaction? d. Calculate the rate constant for the reaction.
Explanation:
H2 (g) + 2NO(g) → N2O(g) + H2O(g)
Trial 1 Trial 2 Trial 3
H2 (M) 0.30 0.60 0.60
NO (M) 0.35 0.35 0.70
Rate (M*s) 2.835 x 10^-3 1.134 x 10^-2 2.268 x 10^-2
a. What is the order with respect to H2?
Comparing trial 1 and 2, the conc of H2 is doubled, the rate of the reaction increased by a factor f 4. This means the rate is in second order with respect to H2.
b. What is the order with respect to NO?
Comparing Trial 2 and 3, the concentration of NO is doubled, the rate of the reaction increased by a factor of 2. This means the rate is in first order with respect to NO.
c. What is the rate equation for this reaction?
The rate equation is given as;
rate = k [H2]²[NO]
d. Calculate the rate constant for the reaction.
Taking trial 1;
2.835 x 10^-3 = k (0.30)²(0.35)
k = 2.835 x 10^-3 / 0.0315 = 90 x 10^-3
k = 0.09 L2 mol-2 s-1
What can be observed when concentrated nitric acid is added to iron two sulfate solution?
Answer:
It will produce iron(III) sulphate ,nitrogen dioxide and water
Explanation:
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if I'm correct do mark my answer as brainliest
A glass of water weighs 40g and on adding ice to it weighs 250g. How much ice is added to glass.
Answer:
[tex]\huge\boxed{\sf Ice\ Added = 210\ g}[/tex]
Explanation:
Weight of glass of water before adding ice = 40 g
Weight of glass of water after adding ice = 250 g
Ice Added = 250 g - 40 g
Ice Added = 210 g
Choose the best description for the indicated bond H-CEC-CH3 A) This is a triple bond between two carbons in which three pi bonds hold the atoms together. B) This is a single bond between two carbons formed by the overlap of an sp orbital on each carbon. Extra electrons on each carbon exist as lone pairs in p orbitals. C) This is a triple bond between two carbons in which a sigma bond arises from sp- sp overlap and two pi bonds are formed by side-to-side overlap of unhybridized p orbitals on each carbon. D) This is a triple bond between two carbons in which there are three sigma bonds between the atoms, which are each spa hybridized
Answer:
(Chemical compound and indicated bond in attachment).
C) This is a triple bond between two carbons in which a sigma bond arises from sp- sp overlap and two pi bonds are formed by side-to-side overlap of unhybridized p orbitals on each carbon.
Explanation:
Alkynes are hydrocarbons that contain carbon-carbon triple bonds. Each carbon atom is bound to the other two atoms, and there are no free valence electrons. Each carbon atom needs two hybrid orbitals to form the skeleton of sigma bonds. The hybridization of the s orbital with a p orbital generates two hybrid orbitals, oriented at 180º of separation for each carbon atom. The overlap of these hybrid orbitals sp with the s orbitals from the hydrogen produces the skeleton of sigma bonds.
The result of the overlap of the two remaining unhybridized p orbitals of each atom of carbon is the formation of two pi bonds. These orbitals overlap in right angles with each other, forming a pi bond with electronic density above and below the sigma bond and the other with electronic density in front of and behind the sigma bond. The form of these pi bonds is such that they combine to form a cylinder of electron density that "wraps" the sigma bond between the two carbon atoms.