Barium – 122 has a half-life of 2 minutes. Suppose you obtain a sample weighing 20.0 g and it takes 10 minutes to set up an experiment. How many grams of Barium – 122 will remain at the point when you begin the experiment?
If 4.00 g of the unknown compound contained 0.133 mol of C and 0.267 mol of H. how many moles of oxygen, O
were in the sample?
Express your answer to three significant figures and include the
Answer:
Explanation:
convert to grams
0.133 mol C x 12 = 1.596
0.267 mol H x 1 = 0.267
Now subtract those numbers from the 4.00
4.00-1.596 -0.267 = 2.137 g O
Now convert grams O to moles
2.137 x (1mole O/16 g O) =0.1335625 moles O
3 sig figs = 0.134 moles O
Write a balanced chemical equation for the reaction between aqueous hydrogen ion, H+, and aqueous hydroxide ion, OH+
H+ (aq) + OH- (aq) → H2O (l)
On a distance time graph of an objects motion distance is usually what
Ten years ago, a vacant lot in a subdivision was purchased for $30,500. The owner hired a general contractor to build a home on the lot. The contractor charged $375,000. The homeowner is planning to refinance the mortgage. The bank recently appraised the home at $410,000. What is the value of the property?
The value of the property at the end of the given time period is determined as $410,000.
What is the value of the property?The value of the property is the sum of the purchase price of the lot and the cost of building the home, which is:
$30,500 (purchase price of the lot) + $375,000 (cost of building the home) = $405,500
However, the bank has appraised the home at $410,000, which means that the value of the property has increased by $4,500.
Therefore, the value of the property is:
$405,500 (original value) + $4,500 (increase in value) = $410,000.
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A + B = AB is an example of a ________reaction
Answer:
A + B = AB is an example of a synthesis reaction
Explanation:
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.
Problem 1. What masses of 15% and 20% solutions are needed to prepare 200 g of 17% solution?
Problem 2. What masses of 18% and 5% solutions are needed to prepare 300 g of 7% solution?
Problem 3. 200 g of 15% and 350 g of 20% solutions were mixed. Calculate mass percentage of final solution.
Problem 4. 300 g of 15% solution and 35 g of solute were mixed. Calculate mass percentage of final solution.
Problem 5. 400 g of 25% solution and 150 g of water were mixed. Calculate mass percentage of final solution.
Problem 1:
we need 80 g of the 15% solution and 120 g of the 20% solution.
Let x be the mass of the 15% solution needed and y be the mass of the 20% solution needed.
x + y = 200 (total mass of the two solutions)
0.15x + 0.2y = 0.17(200) (total amount of solute in the two solutions)
Solving these equations, x = 80 g and y = 120 g.
Therefore, we need 80 g of the 15% solution and 120 g of the 20% solution.
Problem 2:
we need 120 g of the 18% solution and 180 g of the 5% solution.
Let x be the mass of the 18% solution needed and y be the mass of the 5% solution needed.
x + y = 300
0.18x + 0.05y = 0.07(300)
Solving these equations, x = 120 g and y = 180 g.
Therefore, we need 120 g of the 18% solution and 180 g of the 5% solution.
Problem 3:
The mass percentage of the final solution is 135 g/550 g × 100% = 24.55%.
The total mass of the final solution is 200 g + 350 g = 550 g.
The total amount of solute in the final solution is:
0.15(200 g) + 0.20(350 g) = 65 g + 70 g = 135 g.
Therefore, the mass percentage of the final solution is 135 g/550 g × 100% = 24.55%.
Problem 4:
The mass percentage of the final solution is 110 g/335 g × 100% = 32.84%.
The total mass of the final solution is 300 g + 35 g = 335 g.
The total amount of solute in the final solution is:
0.15(300 g) + 35 g = 75 g + 35 g = 110 g.
Therefore, the mass percentage of the final solution is 110 g/335 g × 100% = 32.84%.
Problem 5:
The mass percentage of the final solution is 18.18%.
Calculate the final mass of the solution:
Final mass = 400 g + 150 g = 550 g
Calculate the mass of solute in the 25% solution:
Mass of solute = 0.25 x 400 g = 100 g
Calculate the mass percentage of the final solution:
Mass percentage = (mass of solute ÷ final mass) x 100%
Mass percentage = (100 g ÷ 550 g) x 100%
Mass percentage = 18.18%
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dry ice is solid carbon dioxide. represent carbon dioxide in the following three ways, symbolic, particulate. and macroscopic
In symbol form, ice is depicted as CO2, in particle form, as molecules of CO2 packed closely together, and in macroscopical form, as a white, crystalline substance that sublimates from a solid to a gas.
How is dry ice defined as solid carbon dioxide?Because the gas when it solidifies resembles ice, ice ice is actually just carbon dioxide that has been solidified. Unlike regular ice, it instantly transforms into CO2 gas instead of melting into a liquid.
Why is dry ice a good illustration of sublimation?Solid carbon dioxide is sometimes referred to as "dry ice." That's because when something warms up and changes state, it doesn't just dissolve into a liquid. Instead, it skips the liquid step and transforms right into a gas.
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which statement describes density? Check all that apply
Density is a chemical property of an object.
The density of an object is constant.
Density is a derived unit of measure.
Density is the sum of the mass and volume of an object.
The density of an object determines whether it will sink or float.
The following sentences describe density: An object's density is constant. A derived unit of measurement called density An object's density determines whether it will float or sink.
Is an object's density a chemical characteristic?Without affecting the thing's makeup, the mass of an object can be measured. The volume of an object is comparable in this regard. As a result, there is no requirement for a chemical reaction to determine an object's density, making density a physical feature.
Is density a chemical or physical characteristic?Physical properties are characteristics of matter that are independent of changes in its chemical composition. Physical characteristics include things like density, colour, hardness, melting, and boiling points.
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The diagram below represents a specimen in the low-power field of view of a compound light microscope. If the slide is not moved, which view best represents the way the specimen will look when the high-power objective lens is switched into place?
Coarse and excellent adjustment The coarse adjustment knob solely be used with the lowest electricity objective lens. Once it is in focus, you will only need to use the best focus. Using the coarse center of attention with greater lenses may result in crashing the lens into the slide.
Why does the specimen have to be founded in the field of view on low strength before going to high power?You must have the object situated before you exchange objectives to increase the magnification, because the subject of view turns into smaller; if the object is off to the side, it might also disappear when you go to higher magnification.
When viewing a specimen on a compound light microscope the photograph is right aspect up but reversed True or false?The optics of a microscope's lenses alternate the orientation of the photo that the consumer sees. A specimen that is right-side up and going through proper on the microscope slide will appear upside-down and going through left when considered through a microscope, and vice versa.
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Please help almost due?
Answer:
-lithium
-atomic number
-mass number
-protons
Explanation:
4 Read the sentence from the introduction [paragraph 1].
Matter is capable of undergoing changes, which are classified as either physical or chemical.
Which phrase could BEST replace "is capable of undergoing" in the sentence above?
(A) has the knowledge to perform
(B) has the ability to experience
(C) has the experience to recognize
(D) has the opportunity to facilitate
Answer: A
Explanation:
You thought i was feeling you that n was a munch
How many molecules of HCI are in 4.91 L of HCI acid at 25°C if the density equals 1.096 g/ml
To determine the number of HCl molecules in 4.91 L of HCl acid at 25°C, we can use the following steps:
Calculate the mass of the HCl acid in 4.91 L using its density.Convert the mass of HCl acid to the number of moles using its molar mass.Use Avogadro's number to convert the number of moles of HCl to the number of HCl molecules.Calculate the mass of the HCl acid in 4.91 L using its density:[tex]\qquad\sf {Density = \dfrac{mass}{volume}}[/tex]
[tex]\qquad\sf{mass = density \times volume}[/tex]
[tex]\qquad\sf{mass = 1.096 \: g/mL \times 4.91\: L = 5.38\: kg}[/tex]
Convert the mass of HCl acid to the number of moles using its molar mass. The molar mass of HCl is 36.46 g/mol.
[tex]\sf{moles = \dfrac{mass}{ molar\: mass} = \dfrac{5.38\: kg}{36.46\: g/mol} = 147.6\: mol}[/tex]
Use Avogadro's number to convert the number of moles of HCl to the number of HCl molecules. Avogadro's number is [tex]6.02 \times 10^23[/tex] molecules/mol.
[tex]\sf number\: of\: HCl\: molecules = moles \times Avogadro's\: number[/tex]
[tex]\begin{aligned}\sf number\: of\: HCl\: molecules& =\sf 147.6 \: mol \times 6.02 \times 10^23\: molecules/mol \\& =\sf 8.88 \times 10^25\: molecules\end{aligned}[/tex]
Therefore, there are [tex]8.88 \times 10^25[/tex] HCl molecules in 4.91 L of HCl acid at 25°C, assuming the density of the acid is 1.096 g/mL.
[tex]\rule{200pt}{5pt}[/tex]
1. Use the bond enthalpies to calculate the enthalpy change for this reaction. Is this reaction endothermic or exothermic?
Change in enthalpy =
Is this reaction exothermic or endothermic?
If bond formation in the products releases more heat energy than bond breaking in the reactants does.
Endothermic is either hot or cold.The reverse of exothermic processes is endothermic reactions. They take in thermal energy from the environment. This indicates that endothermic reactions cause their surroundings to get colder. This kind of response can be seen in the melting of ice.
What does it mean to be endothermic?An organism is said to be endothermic if it expends energy to control the internal temperature of its body. Ectothermic organisms, on the other hand, are those that control their body temperature through external environmental stimuli.
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What is the ratio of ammonia if the chemical formula is
NH3
Explanation:
The chemical formula NH3 represents ammonia, a colorless gas that is widely used in various industrial and household applications. The formula indicates that one molecule of ammonia contains one nitrogen atom and three hydrogen atoms. Therefore, the ratio of nitrogen to hydrogen in ammonia is 1:3.
This means that for every one nitrogen atom in an ammonia molecule, there are three hydrogen atoms. Alternatively, we can say that the ratio of nitrogen atoms to hydrogen atoms in ammonia is 1:3.
What is the hydroxide ion concentration of a solution
with a pOH of 5.0?
Select one:
a 5.0 x 10¹¹ M
b 1.0 x 105 M
c 1.0 x 10⁹ M
d 1.0 x 109 M
Answer: 1.0 X 10^-5 M
Explanation:
to change pOH to OH- it is judt 1 X 10-pOH
so it is 1 x 10^-5
5.0 L of a gas goes from 1.0 atm to 1.3 atm.
Calculate the final volume of this gas.
A 6.5 L
B 0.26 L
C 4.1 L
D 3.8 L
Answer: D) 3.8 L
Explanation:
Boyles law
P1v1=p2v2
V2= p1v1/p2
v2= 1.0 x 5.0 /1.3 = 3.84 L
Which emission spectrum represents the copper?
A.) Spectrum A
B.) Spectrum B
C.) Spectrum C
The emission spectrum of copper can be seen from the spectrum C
What is the emission spectrum?
An emission spectrum is the pattern of wavelengths of electromagnetic radiation emitted by a substance when it is excited by heat, electricity, or some other energy source. Each element, molecule, or compound has a unique emission spectrum, which can be used to identify it or to study its physical and chemical properties.
The emission spectrum is produced when electrons in the atoms or molecules are excited to higher energy levels, and then return to their ground state by releasing energy in the form of photons. The energy of each photon corresponds to a specific wavelength, and the collective emission of all the photons produces a characteristic pattern of bright lines or bands in the electromagnetic spectrum.
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The scientific notation of 45,000
Hydrogen (10 points)
14. What does using hydrogen as a fuel source mean? How is it combined to create an energy source?
15. Explain where hydrogen is found. What are sources of hydrogen found on Earth?
16. Name and explain 3 advantages/disadvantages of using hydrogen as a fuel source and how it compares to using fossil fuels and other alternative energies (specifically include environmental issues that can happen.
17. What is a fuel cell? How does it work? (include diagram)
Solar Power (10 points)
18. What is a good definition of solar energy?
19. How does a solar cell make electricity? What is it made of?
20. Name and explain 3 advantages/disadvantages about solar energy to heat or produce electricity compared to using fossil fuels or other alternatives (specifically include environmental issues that can happen.
21. Find an example of solar energy being used in the U.S.?
An example of solar energy being used in the U.S is in the heating of swimming pools, and powering of cabins in off grid regions.
Hydrogen and Solar Energy14. Using hydrogen as a fuel source involves using it as a primary energy carrier to power vehicles or generate electricity. It can be combined with oxygen to create water, producing energy in the process. The process of using hydrogen as a fuel source is known as hydrogen fuel cell technology, which involves the conversion of chemical energy into electrical energy.
15. Hydrogen is the most abundant element in the universe but is rarely found in its pure form on Earth. It is usually found in combination with other elements such as oxygen in water, carbon in hydrocarbons, and nitrogen in ammonia. Hydrogen can be extracted from water, natural gas, coal, and biomass through various methods such as steam-methane reforming, electrolysis, and biomass gasification.
16. Advantages of using hydrogen as a fuel source include:
It is a clean energy source that produces no greenhouse gases or air pollutants when burned, emitting only water vapor and heat.It is highly efficient, with a higher energy density than fossil fuels, making it a potent source of energy for transportation and electricity generation.It can be produced from a wide variety of domestic and renewable sources, reducing reliance on imported oil and promoting energy independence.Disadvantages of using hydrogen as a fuel source include:
It is expensive to produce, store, and transport, making it less cost-effective than fossil fuels and other alternative energies.It requires a lot of energy to produce, mainly from fossil fuels, which defeats the purpose of using it as a clean energy source.The infrastructure for hydrogen fuel cell technology is not yet well established, limiting its widespread adoption and use.17. A fuel cell is an electrochemical device that converts chemical energy into electrical energy through a chemical reaction between hydrogen and oxygen. It consists of an anode, a cathode, and an electrolyte, with the hydrogen fuel entering the anode and the oxygen entering the cathode. The hydrogen molecules are split into protons and electrons, with the protons passing through the electrolyte and the electrons flowing through an external circuit, generating electricity. The oxygen combines with the protons and electrons at the cathode, producing water as the only byproduct.
18. Solar energy is a form of renewable energy that is derived from the sun's radiation. It is harnessed through various technologies such as photovoltaics, solar thermal systems, and concentrated solar power to generate electricity, heat water, and power homes and businesses.
19. A solar cell is a semiconductor device that converts sunlight directly into electricity through the photovoltaic effect. It is made of a thin layer of a semiconductor material such as silicon that is treated with impurities to create a p-n junction. When sunlight strikes the cell, it creates an electric field that separates the positively charged holes and negatively charged electrons, generating an electric current.
20. Advantages of using solar energy include:
It is a clean and renewable energy source that produces no greenhouse gases or air pollutants when used.It is becoming more cost-effective, with the cost of solar panels decreasing over time and becoming more efficient.It can be installed on rooftops or in remote areas, reducing the need for extensive power lines and infrastructure.Disadvantages of using solar energy include:
It is dependent on sunlight and may not be available at all times, requiring energy storage or backup systems.It requires large surface areas to generate significant amounts of electricity, making it unsuitable for densely populated urban areas.The production of solar panels requires toxic chemicals and materials that can harm the environment if not disposed of properly.21. An example of solar energy being used in the U.S is in the heating of swimming pools, and powering of cabins in off grid regions.
If only 1600 grams of CO2 are produced, what is the percent error of this reaction?
Answer:
Explanation:
MTBE (C5H12O)
what happens in a synthesis reaction
Esters, amines, and amides have many uses in medicine. Investigate one of the following drugs further: aspirin, Benadryl, or Tylenol and give its scientific name. What kind of functional groups does it contain?
Esters, amines, and amides have many uses in medicine, and so do carboxylic acids, such as aspirin. Aspirin is the drug that will be investigated further. Its scientific name is acetylsalicylic acid.
What kind of functional groups does Aspirin contain?Acetylsalicylic acid contains two functional groups: a carboxylic acid group (-COOH) and an ester group (-COO-CH₃). The carboxylic acid group is responsible for the acidic properties of aspirin and allows it to form salts with bases. The ester group is formed from the reaction between the carboxylic acid group of salicylic acid and acetic anhydride. This esterification reaction makes aspirin more soluble in organic solvents and less irritating to the stomach than salicylic acid.
Aspirin is a widely used medication that has anti-inflammatory, analgesic, and antipyretic properties. It works by inhibiting the production of prostaglandins, which are responsible for pain, inflammation, and fever. Aspirin is commonly used to treat headaches, fever, arthritis, and other inflammatory conditions. It is also used as a blood thinner to prevent heart attacks and strokes.
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How many moles of Ca are required to react with 2.50 mol of Cl to produce the compound CaCl2
Answer:
1.25 moles
Explanation:
The balanced chemical equation for the reaction between Ca and Cl to produce CaCl2 is:
Ca + Cl2 → CaCl2
The stoichiometry of the balanced equation tells us that one mole of Ca reacts with one mole of Cl2 to produce one mole of CaCl2. Therefore, to find out how many moles of Ca are required to react with 2.50 mol of Cl, we need to divide 2.50 mol of Cl by the coefficient of Cl2 in the balanced equation, which is 2:
2.50 mol Cl ÷ 2 = 1.25 mol Ca
Therefore, 1.25 moles of Ca are required to react with 2.50 mol of Cl to produce the compound CaCl2.
A buffer solution is made using weak acid, HA, with a pKa of 6.98. If the ratio of [A-] to [HA] is 1.0 x 10^3, what is the pH of the buffer
Carbon dioxide is an example of a greenhouse gas. Levels of carbon dioxide are increasing in the atmosphere. How are increasing levels of carbon dioxide affecting the atmosphere?
Select the two correct awnsers.
1.less water is evaporating from the oceans
2. Earthquakes and volcanic eruptions are becoming more frequent
3.patterns of rain and snow are changing
4.ice caps are becoming thicker and wider at the North Pole and South Pole
5.oceans waters are becoming warmer
Global warming brought on by rising carbon dioxide concentrations in the atmosphere is changing weather patterns and ocean temperatures. Changes in precipitation patterns are being brought on by the warming of the atmosphere.
Why does carbon dioxide serve as a representative greenhouse gas?Because it is one of the gases in the atmosphere that causes the greenhouse effect, which causes the Earth to warm, carbon dioxide is known as a greenhouse gas. Long-wavelength infrared radiation (heat) from the Earth is absorbed by carbon dioxide molecules in the atmosphere, and some of it is then radiated back downward.
What impact does an increase in atmospheric carbon dioxide have?Similarly, as air temperatures rise in response to rising carbon dioxide concentrations, more water vapor escapes into the atmosphere—which then amplifies greenhouse heating
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A 6.55 g sample of aniline (C6H5NH2, molar mass = 93.13 g/mol) was combusted in a bomb calorimeter. If the temperature rose by 32.9°C, use the information below to determine the heat capacity of the calorimeter. 4 C6H5NH2(l) + 35 O2(g) → 24 CO2(g) + 14 H2O(g) + 4 NO2(g)
We must first determine how much heat is produced by the combustion of aniline. According to the chemical equation, 4 moles of aniline react with 35 moles of oxygen to create 4 moles of nitrogen dioxide, 24 moles of carbon dioxide, and 14 moles of water. The mole ratio of aniline to heat emitted is as a result.
How much energy is emitted when one mol is created?When one mole of water is created from hydrogen and oxygen in the opposite reaction (equation d), it exhales 285.8 kJ of energy.
How much heat energy is released when 1.8 g of glucose is burned?
C₆H₁₂O₆(s)+6O₂(g)→6CO₂(g)+6H₂O(l); ΔH = −2900kJ
One mole (about 180g) of glucose burned during combustion, releasing 2900kJ (29001801.8=29kJ) in heat.
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Problem 1. What masses of 15% and 20% solutions are needed to prepare 200 g of 17% solution?
Problem 2. What masses of 18% and 5% solutions are needed to prepare 300 g of 7% solution?
Problem 3. 200 g of 15% and 350 g of 20% solutions were mixed. Calculate mass percentage of final solution.
Problem 4. 300 g of 15% solution and 35 g of solute were mixed. Calculate mass percentage of final solution.
Problem 5. 400 g of 25% solution and 150 g of water were mixed. Calculate mass percentage of final solution.
For each problem:
Masses of solution needed are 80 g and 120 g respectively.Masses of solution needed are 120 g and 180 g respectively.Mass percentage of final solution is 22.7%.Mass percentage of final solution is 23.9%Mass percentage of final solution is 18.2%.How to calculate mass and mass percentage?Problem 1:
Let x be the mass of the 15% solution needed and y be the mass of the 20% solution needed.
We have two equations:
x + y = 200 (total mass of the solution)
0.15x + 0.20y = 0.17(200) (total amount of solute in the solution)
Solving these equations:
x = 80 g (mass of 15% solution needed)
y = 120 g (mass of 20% solution needed)
Therefore, 80 g of 15% solution and 120 g of 20% solution need to be mixed to prepare 200 g of 17% solution.
Problem 2:
Let x be the mass of the 18% solution needed and y be the mass of the 5% solution needed.
We have two equations:
x + y = 300 (total mass of the solution)
0.18x + 0.05y = 0.07(300) (total amount of solute in the solution)
Solving these equations:
x = 120 g (mass of 18% solution needed)
y = 180 g (mass of 5% solution needed)
Therefore, 120 g of 18% solution and 180 g of 5% solution need to be mixed to prepare 300 g of 7% solution.
Problem 3:
Let x be the mass of the final solution.
The total amount of solute in the final solution is:
0.15(200 g) + 0.20(350 g) = 55 g + 70 g = 125 g
The total mass of the final solution is:
200 g + 350 g = 550 g
Therefore, the mass percentage of the final solution is:
(125 g / 550 g) x 100% = 22.7%
Problem 4:
Let x be the mass of the final solution.
The total amount of solute in the final solution is:
0.15(300 g) + 35 g = 80 g
The total mass of the final solution is:
300 g + 35 g = 335 g
Therefore, the mass percentage of the final solution is:
(80 g / 335 g) x 100% = 23.9%
Problem 5:
Let x be the mass of the final solution.
The total amount of solute in the final solution is:
0.25(400 g) = 100 g
The total mass of the final solution is:
400 g + 150 g = 550 g
Therefore, the mass percentage of the final solution is:
(100 g / 550 g) x 100% = 18.2%
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How many moles of MgS are in 100.g MgS?
Answer:
Explanation:
100/56 = 1.79 moles MgS
56 came from the periodic table for Mg and S