Answer:
The energy change in a chemical reaction is due to the difference in the amounts of stored chemical energy between the products and the reactants. This stored chemical energy, or heat content, of the system is known as its enthalpy.
Explanation:
Due to the absorption of energy when chemical bonds are broken, and the release of energy when chemical bonds are formed, chemical reactions almost always involve a change in energy between products and reactants. By the Law of Conservation of Energy, however, we know that the total energy of a system must remain unchanged, and that oftentimes a chemical reaction will absorb or release energy in the form of heat, light, or both.
How many moles of KOH are there in 27.5 mL of 0.250 M KOH?
Question 2 options:
4.31 × 10−3 mol KOH
6.88 × 10−3 mol KOH
7.24 × 10−3 mol KOH
8.13 × 10−3 mol KOH
9.21 × 10−3 mol KOH
Answer:
6.88 × 10^-3mol
Explanation:
Molarity = number of moles (n) ÷ volume (V)
According to this question, there in 27.5 mL of 0.250 M KOH, the number of moles of KOH can, therefore, be calculated as follows:
number of moles = molarity × volume
Volume of KOH = 27.5mL = 27.5/1000
= 0.0275L
n = 0.0275 × 0.250
n = 0.006875 mol
n = 6.88 × 10^-3mol
what is the difference between double salt and complex salt
Answer:
The main different of double salt and complex salt is that a double salt is a combination of two salt compounds whereas a complex salt is a molecular structure that is composed of one or more complex ions.
I need help with question 5
Answer:
B a spring being stretched
The carbon atom forms a part of all the major molecules found in living things. Which of the following doesnot contain carbon?
Hydrochloric acid or Hcl
Combustion reactions typically involve all of the following except
a. The consumption of oxygen gas
b. The production of a Hydrocarbon
c. The production of water
d. The release of carbon dioxide
Answer:
b. The production of a HydrocarbonExplanation:
In Combustion reaction usually occurs when a hydrocarbon reacts with oxygen to produce carbon dioxide and water.
A pupil has drawn the electronic structure of fluorine and the diagram is shown below. However,
mistakes have been made. State three mistakes that have been made.
Fl atomic number: 9
Fl atomic mass: 10
(ps i have two of these but can’t figure out the last)
Answer:
The number of electrons in the orbit is wrong they have to be 9 and not 10since flourine is in group 7 the number of electrons in the outer most shell has to be 7 and not 2the first shell has 8 instead of 2 electronsI hope this helps
The Clean Air Act legislation of 1970, 1977, and 1990 was designed to improve air quality in the United States by monitoring and reducing the emissions of air pollutants judged to pose threats to human health, such as carbon monoxide, nitrogen dioxide, sulfur dioxide, ozone, particulate matter, and lead. The main source of lead emissions in 1970 was the exhaust of vehicles burning gasoline to which tetra-ethyl lead had been added to improve combustion. By 1985, leaded gasoline was phased out of use, although airplanes and racecars were exempted. The 1990 amendments addressed the growing problem of urban smog by
Answer:
The 1990 amendments addressed the growing problem of urban smog by acid rain.
Explanation:
As shown in the above question, the Clean Air Act was created with the goal of making the US air healthier, while also aiming to reduce the impacts of pollution on the American population. This law had as its main objective to reduce the emission of gases capable of polluting the atmosphere, especially those resulting from the burning of gasoline in cars. In 1990, a new amendment was added to this law. This amendment aimed to reduce emissions of sulfur dioxide and nitrogen oxides, as they were the main cause of acid pollution, which was responsible for acid rain that is extremely dangerous and negative for society.
PLEASE HELPP!!!
PLEASE HELP!!!
Write the sentences in your copybook and draw a line through one of the words in
bold to complete each of these sentences about alkali metals correctly.
Alkali metals generally become more / less dense going down the group.
The melting and boiling points of alkali metals increase / decrease down the group.
The softness of alkali metals increases / decreases going down the group.
The speed with which alkali metals react with oxygen increases / decreases going
down the group.
Answer:
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How many moles are in 32g of O2?
Answer:
1 mol of O2
Explanation:
n = m/ M
n = 32/ ( 2× 15.999)
n= 1 mol of O2
Which statement includes all the steps in the change that is associated with the enthalpy of solution? solute separation and mixing reaction of reactants to form products. solute and solvent mixing and then separating solute separation, solvent separation, and then mixing
Answer: solute separation, solvent separation, and then mixing
Explanation:
The enthalpy change of solution simply means the amount of heat which can be released or absorbed when dissolving. The enthalpy of solution is usually expressed at constant temperature in kJ/mol.
The enthalpy of solution requires three main stages:
1. Solute separation: This is when the solute is broken down. In this case, all the intramolecular forces which holds the solute together is broken.
2. Solvent separation: This is when the solvent is broken down all the intramolecular forces which holds the solvent together is broken.
3. Mixing- In this case, the solute and the solvent is mixed for a solution.
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Answer:
64g of [tex]\bold{CH_{3}OH}\dashrightarrow[/tex]44.8L
vapour density of [tex]CH_{3}3OH=\frac{mass}{volume}[/tex] of [tex]\bold{CH_{3}OH}[/tex]
=64/44.8=10/7=1.43 g/l
Vapour density of [tex]\bold{CH_{3}OH}[/tex]=1.43g/l
64g of [tex]\bold{CH_{3}OH => 44.8L }[/tex]
vapour density of [tex]\small{\sf{CH_{3}3OH=\frac{mass}{volume} of } \bold{CH_{3}OH}}[/tex]
=64/44.8=10/7=1.43 g/l
Vapour density of [tex]\bold{CH_{3}OH = 1.43 g/L}[/tex]
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Explanation:
a) HNO2(aq) = HNO3(aq) + H2O(l) +NO(g)
b) SoCl2 (l) + H2O (l) = So2(g) + 2HCl(aq)
c) CH4 (g) + 2O2(g) = Co2 (g) + 2H2O(g)
d) 3CuO(s) + 2NH3 (g) = 3Cu(s) + 3H2O (l) + N2(g)
what is a measureing tape used for
Answer:
It is used to measure size or distance.
Answer:
it is used to measure long heights and distances and lengths,it is yellow and goes round
Explanation:
How many atoms of hydrogen are there in 36 g of NH4?
Answer:
hope it helps you
Explanation:
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what is the charge on ion X Li2X
In the compound Li2X, there are two lithium ions and one X^2- ion.
Ionic compounds are composed of an ion pair of opposite charge. Usually, the positive ion is a metal cation while the negative ion is a non metal anion. The two ions are held together by strong electrostatic interaction.
In the compound Li2X, there are two lithium ions and one X^2- ions. X^2 -is the non metal anion present.
Learn more: https://brainly.com/question/2673886
Plants in forests take up carbon dioxide from the atmosphere during photosynthesis. They transform the carbon dioxide into plant material. When plants die, their organic matter is often worked into the soil by decomposers. Some of this organic matter remains within the soil and forest floor, and some of it is taken up by other living things.
Based on this information, what role do forests play in the carbon cycle?
A.
Forests are carbon sinks because they store carbon.
B.
Forests are carbon sinks because they do not absorb carbon dioxide when plants die.
C.
Forests are carbon sources because they emit carbon.
D.
Forests are carbon sources because they can be burned to emit carbon dioxide.
Answer: B. forests are carbon sinks because they store carbon
Explanation:forests take up carbon from the atmosphere through photosynthesis and from organic matter through decomposition. so, forests are carbon sinks because they store carbon
How does the position of an object relate to the energy stored in a object?
Answer:
An object can store energy as the result of its position. For example, the heavy ball of a demolition machine is storing energy when it is held at an elevated position. This stored energy of position is referred to as potential energy. Similarly, a drawn bow is able to store energy as the result of its position
Answer:
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What must scientists look for in their experiment or their data to make sure it is accurate?
Answer:
Scientists must look in their experiment/data to check for accuracy because they don't want to make any mistakes, and most importantly have to make sure they have the right information to proceed.
Explanation:
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Plz Help I have One more time To retake and I can't fail it..
Answer:
D
Explanation:
A synthesis reaction is a reaction in which two or more reactants combine to form a given product.
If we look closely at option D, you will notice that sulphur and oxygen combined together to form sulphur dioxide. That is a typical example of chemical synthesis.
Hence;
S + O2 ----->SO2 is a synthesis reaction.
Need help fast!!
What is the pH of a solution with a 1.50 x 10-9 M hydroxide ion concentration? (4
points)
1) 0.176
2) 5.18
3) 8.82
4) 9.20
Answer:
The answer is "5.18 ".
Explanation:
It's a question of chemistry. Therefore, the following solution is provided:
We will first determine the solution's pOH. The following can possible:
The concentration of Hydroxide ion [tex][OH^{-}] = 1.5\times 10^{-9}\ M[/tex]
[tex]pOH =?\\\\pOH = -\log [OH^{-}]\\\\pOH = -\log 1.5\times 10^{-9}\\\\pOH = 8.82\\\\[/tex]
Furthermore, the pH of the solution shall be established. It was provided as follows:
[tex]pOH = 8.82\\\\pH =?\\\\pH + pOH = 14\\\\pH + 8.82 = 14\\\\[/tex]
When collecting all the like terms:
[tex]pH = 14 -8.82\\\\pH = 5.18[/tex]
Therefore, the solution of pH is 5.18.
If 3.5 kJ of energy are added to a 28.2 g sample of iron at 20 degrees C, what is the final temperature of the iron in kelvins?
295.8k
that is the procedure above
2.0 kilograms of lithium hydroxide can “scrub”, or remove, how many liters of carbon dioxide at standard conditions?
Answer:
0.94 L
Explanation:
The equation of the reaction is;
2LiOH + CO2 -----> Li2CO3 + H2O
Number of moles LiOH = 2.0/23.95 g/mol = 0.084 moles
2 moles of LiOH scrubs 22.4 L of CO2
0.084 moles of LiOH scrubs 0.084 moles × 22.4/2
= 0.94 L
What has an atomic number of 1
Answer:
Hydrogen
Explanation:
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Explanation:
a) The presence of sulfate ions in a solution can be confirmed by the reaction of barium chloride in an acidic medium.
The balanced chemical equation of the reaction is shown below:
[tex]BaCl_2(aq)+CuSO_4(aq)->CuCl_2(aq)+BaSO_4(s)[/tex]
Hence, the white precipitate is barium sulfate and its formation with the ionic equation is shown below:
[tex]Ba^2^+(aq)+SO_4^2^-(aq)->BaSO_4(aq)[/tex]
b) The presence of copper (II) ions can be confirmed by the following test:
Add potassium iodide solution to copper (II) solution.
Then a white ppt of cuprous iodide along with the liberation of iodine is observed and the entire solution attains brown color.
The chemical equation of the reaction is shown below:
[tex]2CuSO_4(aq)+4KI(aq)->Cu_2I_2(s)+I_2(s)+2K_2SO_4(aq)\\[/tex]
c)(i)Due to this reaction, the blue color of the solution becomes white.
Reddish-brown copper is deposited at the bottom of the container.
(ii)In this reaction, zinc is oxidized.
d) (i) Copper is produced at the cathode.
(ii)[tex]Cu^2^+(aq)+2e^-->Cu(s)[/tex]
(iii) The reaction that takes place at the cathode is reduction.
Reduction is gaining of electrons.
The volume of a gas at 6.0 atm is 2.5 L. What is the volume of the gas at 75 atm at
the same temperature? (5 points)
1) 1.0 L
0 2 2) 1.5 L
3) 2.0 L
O 4) 3.0L
The volume of a gas at 6.0 atm is 2.5 L. What is the volume of the gas at 7.5 atm at
the same temperature? (5 points)
1) 1.0 L
2) 1.5 L
3) 2.0 L
4) 3.0L
Answer:
2.0 L
Option C) 2.0L is the correct answer.
Hence, at the same temperature, as the pressure is increased to the given value, the volume of the gas decreases to 2.0L.
Boyle's law
Boyle's law states that "the volume V of a given quantity of gas is inversely proportional to its pressure P as long as temperature remains constant.
Boyle's law is expressed as;
P₁V₁ = P₂V₂
Given the data in the question;
Initial Volume V₁ = 2.5LInitial pressure P₁ = 6.0atmFinal pressure P₂ = 7.5atmFinal volume V₂ = ?To determine the final volume of the gas, we substitute our given values into the expression above.
P₁V₁ = P₂V₂
V₂ = P₁V₁ / P₂
V₂ = ( 6.0atm × 2.5L ) / 7.5atm
V₂ = 15Latm / 7.5atm
V₂ = 2.0L
Option C) 2.0L is the correct answer.
Hence, at the same temperature, as the pressure is increased to the given value, the volume of the gas decreases to 2.0L.
Learn more about Boyle's law here: brainly.com/question/1437490
Which molecule will have the strongest LDF
Answer: Try to get answer in Explanation
Explanation: Kr has a greater number of polarizable electrons (36 electrons), so Kr would have a greater degree of LDFs and therefore a greater melting point than N 2 (which has 7 × 2 = 14 polarizable electrons).
What is nascent hydrogen?
Answer:
[H]
Explanation:
This is nascent hydrogen it's a reactive form of hydrogen...
It reduces elements and compounds.
b) The size of a star is a balance between
2 things. Explain this statement.
Answer:
Luminosity is the amount of light that a star radiates. The size of the star and its surface temperature determine its luminosity. Apparent magnitude of a star is its perceived brightness, factoring in size and distance, while absolute magnitude is its true brightness irrespective of its distance from earth
Explanation:
When it’s summer in the northern hemisphere what Season is it in the Southern Hemisphere
Answer:
Winter
Explanation:
I dont know but whatev
Answer:
Winter
Explanation:
The seasonal cycle in the polar and temperate zones of one hemisphere is opposite to that of the other. Therefore, When it is summer in the Northern Hemisphere, it is winter in the Southern, and vice versa.
hope it helps :)
How much of a sample remains after five half-lives have occurred?
1/5 of the original sample
1/25 of the original sample
1/32 of the original gample
1/64 of the original sample
Answer:
1/32
Explanation:
