Calculate the molarity of each aqueous solution: (a) 25.5 ml of 6.25 m hcl diluted to 0.500 l with water (b) 8.25 ml of 2.00×10–2 m ki diluted to 12.0 ml with water
Final answer:
To calculate the molarity of diluted aqueous solutions of HCl and KI, we apply the dilution formula M1V1 = M2V2, producing final molarities of 0.319 M for HCl and 1.37×10⁻² M for KI.
Explanation:
The question involves calculating the molarity of two different aqueous solutions after dilution. For both parts (a) and (b), we will apply the concept that molarity (M) is the number of moles of solute per liter of solution, and that the number of moles of solute remains constant during the dilution process, allowing us to use the equation M1V1 = M2V2, where M1 and V1 are the initial molarity and volume, respectively, and M2 and V2 are the final molarity and volume, respectively.
For the solution of HCl: Given an initial volume of 25.5 mL (or 0.0255 L) and molarity of 6.25 M, diluted to a final volume of 0.500 L, the final molarity (M2) can be calculated as follows:M2 = (M1 × V1) / V2 = (6.25 M × 0.0255 L) / 0.500 L = 0.319 M.
For the solution of KI: With an initial volume of 8.25 mL (or 0.00825 L) and molarity of 2.00×10⁻² M, diluted to a final volume of 12.0 mL (or 0.012 L), the final molarity is calculated similarly: M2 = (M1 × V1) / V2 = (2.00×10⁻² M × 0.00825 L) / 0.012 L = 1.37×10⁻² M.
A generic gas, x, is placed in a sealed glass jar and decomposes to form gaseous y and solid z. 2x(g)â½ââây(g)+z(s) how are these equilibrium quantities affected by the initial amount of x(g) placed in the container? assume constant temperature.
EASY
Elements in the same period have _____.
similar properties
the same number of protons
the same number of electron shells
the same number of electrons
Answer:
THE SAME NUMBER OF PROTONS
Explanation:
Elements in the same period or row will have the same number of electron shells. So the correct option is C.
What are electron shells?
The electron shell of an atom is the region that surrounds the atomic nucleus which contain a particular number of electrons. Each of the electron orbit allowed has been given a quantum number of n.
It can run from 1, which is for the orbit that is closest to the nucleus to infinity, which is for the orbits totally far from the nucleus. All of the orbitals that have the same value of n constitute an electronic shell.
Inside each of the atomic shells, there are also subshells. These correspond to the different rates of rotation and orientation of the orbitals and also to the directions of the spin of the electrons.
Generally, if the shell is far away from the nucleus or the value of n is higher, the number of subshells will also be higher.
Therefore the correct option is C.
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What is a common way to correct nearsightedness
Nearsightedness or myopia is a condition where the person can see the near objects clearly but distant objects appears blurred. This eye condition is corrected with contact lenses or prescription eyeglasses. Another approach is LASIK or corrective eye surgery. In LASIK laser is used to correct the vision.
Very unsure on my answers for these 2 questions. I really have no idea what I'm doing. Could someone please explain? Will give medal and maybe become a fan if someone would just help me understand! Please?
1. Which of the following energy yields is likely to have come from a fission or fusion reaction?
1.0 × 10^2 kJ/mol
2.5 × 10^2 kJ/mol
1.2 × 10^3 kJ/mol
*This one??? 1.4 × 10^11 kJ/mol
2. In a nuclear reaction, a change in mass of 1.0 × 104 g occurs. What is the corresponding change in energy? Use the formula E = mc2.
9.0 × 10^3 kJ
*My best guess... 9.0 × 10^6 kJ
9.0 × 10^9 kJ
9.0 × 10^12 k
The combustion of ammonia in the presence of excess oxygen yields no2 and h2o: 4 nh3 (g) + 7 o2 (g) → 4 no2 (g) + 6 h2o (g) the combustion of 43.9 g of ammonia produces ________ g of no2.
The combustion of 43.9 g of ammonia produces 118.6 g of NO2.
Explanation:To determine the mass of NO2 produced from the combustion of 43.9 g of ammonia, we first need to calculate the moles of ammonia used. The molar mass of ammonia (NH3) is 17.03 g/mol. We can use the molar ratio from the balanced equation to find the moles of NO2 produced.
4NH3 (g) + 7O2 (g) → 4NO2 (g) + 6H2O (g)
From the balanced equation, the molar ratio between NH3 and NO2 is 4:4. Therefore, the moles of NO2 produced is also equal to the moles of NH3 used. Finally, we can calculate the mass of NO2 produced by multiplying the moles of NH3 used by the molar mass of NO2 (46.01 g/mol).
Mass of NO2 produced = Moles of NH3 used × Molar mass of NO2
Now let's plug in the numbers:
Mass of NO2 produced = 43.9 g × (46.01 g/mol / 17.03 g/mol) = 118.6 g
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The average strength of a hydrogen bond is approximately what percent of the average strength of a covalent bond?
a. 50 %
b. 10 %
c. 5 %
d. 100 %
Hydrogen bonds are
approximately 5% of the bond strength of covalent bonds, for example (C-C or C-H
bonds).
Hydrogen bonds strength in water is approximately 20
kJ/mol, strenght of carbon-carbon bond is approximately 350 kJ/mol
and strengh of carbon-hydrogen bond is approximately 340 kJ/mol.
20 kJ/350 kJ = 0,057 = 5,7 %.
Final answer:
The strength of a hydrogen bond is approximately 5% that of a covalent bond. The correct answer is c. 5%.
Explanation:
The average strength of a hydrogen bond is approximately 5% of the average strength of a covalent bond. Therefore, the correct answer to the question is c. 5%. Hydrogen bonds are a type of intermolecular attractive force where a hydrogen atom covalently bonded to an electronegative atom is attracted to a lone pair of electrons on a neighboring molecule. While hydrogen bonds are much stronger than other dipole-dipole interactions, they are still significantly weaker than covalent bonds, but integral for holding together structures like DNA and proteins in biology.
Claire created a model to study the day and night cycle of Earth as shown here. What causes different points on the globe to receive light at different times, explaining the day and night cycle of Earth?
the rotation of the lamp
the revolution of the lamp
the rotation of the globe
the revolution of the globe
Answer:
the rotation of the globe
Explanation:
As mentioned the model is representing the day and night cycle of earth thus the lamp must be the sun and the globe is earth.
The earth completes one year in taking one complete revolution around the sun (globe revolve around lamp).Thus due to revolution of earth the year gets completed.
The day and night of earth is due to rotation of earth on its own axis. The earth took 24 hours to complete one rotation on its axis.
Thus the rotation of globe causes it to receive light at different times.
A substance is 89.2% carbon by mass. how much of the substance would be needed to recover 34.6 mol of pure carbon?
Answer:
The amount of substance we need to recover 34.6 mol of carbon is 465.47g
Explanation:
we want to know what mass of substance we need to recover 34.6 mol of carbon
This substance is composed of 89.2% carbon
Wmust recover 34.6 mol of carbon and we know that the molecular mass of carbon is 12g / mol this means that one mole of carbon has a mass of 12 g
We use a simple rule of three to know how many grams of carbon are in 34.6 mol
[tex]1 mol C\longrightarrow 12g\\34.6 mol C\longrightarrow x\\x=\frac{(34.6)(12)}{1}= 415.2 g[/tex]
415.2 g are 34.6 mol of carbon
As the amount of carbon we want to recover is 415.2g (34.6mol) and this amount corresponds to 89.2% of the total
To calculate the total mass we need we use a simple rule of three
[tex]89.2\%\longrightarrow 415.2 g\\100\%\longrightarrow x\\x=\frac{(100)(415.2)}{89.2}\\ x= 465.4g[/tex]
The amount of substance we need to recover 34.6 mol of carbon is 465.47g
Which statement about the orinoco river is true.
A. IT FLOWS THROUGH ECUADOR
B. IT IS SECOND LONGEST RIVER IN SOUTH AMERICA
C. IT FLOWS THROUGH VENEZUELA
D. IT EMPTIES INTO THE PACIFIC OCEAN
Katie rolls a toy car off the end of a table
? A B C D
its c just took test
How many moles of co2 are produced when 5.40 mol of ethane are burned in an excess of oxygen?
When 5.40 moles of ethane are burned in excess oxygen, 10.80 moles of carbon dioxide are produced.
The balanced chemical equation for the combustion of ethane (C₂H₆) in oxygen (O₂) is:
C₂H₆ + 7/2 O₂ -> 2 CO₂ + 3 H₂O
From the balanced equation, we can see that 1 mole of ethane (C₂H₆) produces 2 moles of carbon dioxide (CO₂) during combustion. This means that the mole ratio of ethane to carbon dioxide is 1:2.
Given that 5.40 moles of ethane are burned, we can use this mole ratio to calculate the moles of carbon dioxide produced:
5.40 moles of C₂H₆ x (2 moles of CO₂ / 1 mole of C₂H₆) = 10.80 moles of CO₂
So, when 5.40 moles of ethane are burned in excess oxygen, 10.80 moles of carbon dioxide are produced.
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Which of the following is the last step in performing a titration?
a.finding out which pH indicator works
b.determining the concentration of an unknown base
c.finding the number of moles of product produced in a reaction
d.determining the molecular masses of the products in the reaction
The chemical formula for cesium oxide is Cs2O. What is the charge of cesium? +1 +2 –1 –2
Answer:
The correct answer, the charge of Cesium is +1
Explanation:
Hi!
Let's solve this!
The compound is: Cs2O.
We know that the oxygen valence number is -2.
We also know that the compound has to be balanced, so to balance the charges we need +2. As there are two Cs, we perform the following operation:
2 * (+ 1) -2 = + 2-2 = 0
We conclude that the correct answer, the charge of Cesium is +1
Energy can be changed from one form to another. Changes in the form of energy are called energy conversions. In an automobile engine, fuel is burned to convert ________energy into heat energy. The ________energy is then changed into ________energy.
Answer: 1. Chemical energy
2. Mechanical energy
Explanation:
The law of conservation of energy states that energy changes from one form of energy to another but it is neither created nor destroyed.
The fuel consists of chemical energy which when burn results in the release of energy in the form of heat or thermal energy. The heat energy is converted into mechanical energy by the internal machinery of the automobile engine. This mechanical energy is used to run the automobile.
The electromagnetic that is emitted from radioactive elements is released in the form of _____
Gamma Rays
Beta Particles
Neutrons
Alpha Particles
An unknown compound contains only carbon, hydrogen, and oxygen (cxhyoz). combustion of 5.00 g of this compound produced 7.33 g of carbon dioxide and 3.00 g of water. how many moles of carbon, c, were in the original sample?
Answer : The number of moles of carbon in the original sample were 0.166 moles.
Explanation :
The chemical equation for the combustion of hydrocarbon having carbon, hydrogen and oxygen follows:
[tex]C_xH_yO_z+O_2\rightarrow CO_2+H_2O[/tex]
where, 'x', 'y' and 'z' are the subscripts of Carbon, hydrogen and oxygen respectively.
We are given:
Mass of [tex]CO_2=7.33g[/tex]
Mass of [tex]H_2O=3.00g[/tex]
We know that:
Molar mass of carbon dioxide = 44 g/mol
For calculating the mass of carbon:
In 44 g of carbon dioxide, 12 g of carbon is contained.
So, in 7.33 g of carbon dioxide, [tex]\frac{12}{44}\times 7.33=1.99g[/tex] of carbon will be contained.
Now we have to calculate the moles of carbon.
Moles of Carbon =[tex]\frac{\text{Given mass of Carbon}}{\text{Molar mass of Carbon}}=\frac{1.99g}{12g/mole}=0.166moles[/tex]
Therefore, the number of moles of carbon in the original sample were 0.166 moles.
Balance the equation of 2 c6h12o6 + 6 o2--> __ co2 + __ h2o
Consider the chemical equilibrium of the reaction. NH4OH(aq) mc014-1.jpg NH4+(aq) + OHmc014-2.jpg(aq) What will happen to the chemical equilibrium if NH4Cl is added to this solution? The chemical equilibrium will shift to the right. The chemical equilibrium will not shift. The chemical equilibrium will shift to the left. The chemical equilibrium will be lost.
Le chateliers principle is applicable only to reversible reaction not to the irreversible reaction . The equilibrium will shift to the left side of the reaction that is towards the reactant on increasing the amount of NH₄Cl .
What is Le chatelier's principle?According to le chatelier's principle if any change in temperature, pressure or concentration of reactant is brought in the reaction that is in equilibrium then the the equilibrium will shift so as to tend to counteract the effect of the change.
The balanced reaction is
[tex]\rm NH_4OH(aq) \rightleftharpoons NH_4^+(aq) + OH^-(aq)[/tex]
If we add [tex]\rm NH_4Cl[/tex] to the reaction the number of ions of [tex]NH_4^+[/tex] increases in the product side and hence the reaction will counteract to change and equilibrium shift towards left.
Therefore, the equilibrium will shift to the left side of the reaction that is towards the reactant on increasing the amount of NH₄Cl.
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Consider the reaction h2(g) + cl2(g) ⇀↽ 2 hcl(g), which is exothermic as written. what would be the effect on the equilibrium position of increasing the temperature?
Answer:
Backward direction
Explanation:
Exothermic reaction: It is that reaction in which heat is evolved during reaction.
We are given
[tex]H_2+Cl_2\rightleftharpoons 2HCl[/tex]
It is exothermic reaction.
We know that in exothermic reaction when we increase the temperature then the equilibrium shift in backward direction and when we decrease the temperature then the equilibrium shift in forward direction.
Therefore, when we increasing the temperature then the equilibrium shift in backward direction.
Which of the following is an example of symbiosis?
A. A mother bear taking care of her cubs
B. A married couple who split their rent
C. A tick feeding off of its host
D. One chimp cleaning and grooming the hair of another chimp
Answer:
c
Explanation:
im doing it now and the answer above me is wrong
How many moles of oxygen would be needed to react with 6 moles of ethane?
The mole of oxygen needed to react with 6 moles of ethane is 1.16 mol.
What are combustion reactions?Combustion reactions are those in which the substance react with oxygen and produce heat and light.
The reaction will be
[tex]\rm 2C_2H_6 + 7O_2 = 4CO_2 + 6H_2O[/tex]
Now,
[tex]1\; mole\;of \;ethane \times \dfrac{7\;mol\;ofO_2}{6\;mol\;of\;C_2H_6} = 1.16 mol[/tex]
Thus, the moles of oxygen is 1.16 mol.
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Final answer:
To react with 6 moles of ethane, 21 moles of oxygen would be needed.
Explanation:
To determine the number of moles of oxygen needed to react with 6 moles of ethane, we need to use the balanced chemical equation for the reaction. The balanced equation for the combustion of ethane is:
C2H6 + 3.5O2 → 2CO2 + 3H2O
From the balanced equation, we can see that 1 mole of ethane reacts with 3.5 moles of oxygen. Therefore, 6 moles of ethane would require:
(6 moles ethane) * (3.5 moles O2 / 1 mole ethane) = 21 moles of oxygen
The biosphere is made up of parts of which three layers? thermosphere, stratosphere, and lithosphere hydrosphere, thermosphere, and atmosphere lithosphere, stratosphere, and mesosphere hydrosphere, lithosphere, and atmosphere
Please help with chem question
What is the use of calcium chloride?
The combining of the nuclei of atoms is known as nuclear _____.
A.) fission
B.) fusion
C.) bombardment
D.) fallout
Which carbon compound is soft, slippery, a decent electricity conductor, and bonded in a way that forms planes?
coal
petroleum
graphite
Answer:
Graphite.
Explanation:
Hello,
Graphite, plumbago or black lead, is a mineral making up of carbon as its main atom. It has an aromatic-like structure that consists of rings of six carbon atoms assembled in widely spaced horizontal planes. It is extremely soft, and slippery, cleaves at low pressure. Moreover has a very low specific gravity making it a decent electricity conductor. In addition, it successfully withstands heat.
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Which statement describes the structure of an atom?
1)The nucleus contains positively charged electrons.
2)The nucleus contains negatively charged protons.
3)The nucleus has a positive charge and is surrounded by negatively charged electrons
4)The nucleus has a negative charge and is surrounded by positively charged electrons
4)
The correct answer is; "The nucleus has a positive charge and is surrounded by negatively charged electrons"
The atom is composed of three particles, electrons, protons and neutrons.
The electrons are negatively charged, protons are positively charged while neutrons have no charge.
The protons and neutrons are housed in the nucleus of the atom. Since the protons are positively charged, the nucleus is regarded as being positively charged.
The nucleus is surrounded by negatively charged electrons.
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A chemical bond is classified as a covalent bond if it involves the transfer of electrons.
a. True
b. False
Answer:
true
Explanation:
because i said so
If 33.6 grams of KCl are dissolved in 192 grams of water, what is the concentration of the solution in percent by mass? A. 21.2% KCl B. 5.71% KCl C. 14.9% KCl D.17.5% KCl