write the importance of exothermic reactions
Answer: An exothermic reaction is a "reaction for which the overall standard enthalpy change ΔH⚬ is negative." Exothermic reactions usually release heat and entail the replacement of weak bonds with stronger ones.
Exothermic reactions are important to forensic sciences and particularly to fire and explosion investigation. When a chemical reaction requires heat (rather than producing it) and results in cooling down the surroundings, it is conversely called endothermic.
Example-
Respiration is a series of exothermic reactions that occur in the mitochondria of living cells in order to release energy from food molecules. This energy can then be used to produce heat, for movement, growth, reproduction and active uptake.
Hope it helps
A 1.30 L buffer solution consists of 0.107 M butanoic acid and 0.345 M sodium butanoate. Calculate the pH of the solution following the addition of 0.075 moles of NaOH . Assume that any contribution of the NaOH to the volume of the solution is negligible. The Ka of butanoic acid is 1.52×10−5 .
Answer:
The pH of the solution following the addition of 0.075 moles of NaOH is 5.7.
Explanation:
The equation of the buffer solution is the following:
C₄H₇O₂H(aq) + H₂O(l) ⇄ C₄H₇O₂⁻(aq) + H₃O⁺(aq) (1)
The pH of the buffer solution can be found using the Henderson-Hasselbalch equation:
[tex] pH = pKa + log(\frac{[NaC_{4}H_{7}O_{2}]}{[C_{4}H_{8}O_{2}]}) [/tex] (2)
The NaOH added will react with butanoic acid tot produce sodium butanoate:
C₄H₇O₂H(aq) + OH⁻(aq) ⇄ C₄H₇O₂⁻(aq) + H₂O(l) (3)
[tex] n_{C_{4}H_{7}O_{2}H}_{i} = C*V = 0.107 M*1.30 L = 0.139 moles [/tex]
[tex] n_{C_{4}H_{7}O_{2}^{-}} = 0.345 M*1.30 L = 0.449 moles [/tex]
[tex] n_{NaOH} = 0.075 moles [/tex]
[tex] n_{C_{4}H_{7}O_{2}H} = 0.139 moles - 0.075 moles = 0.064 moles [/tex]
[tex] n_{C_{4}H_{7}O_{2}^{-}} = 0.449 moles + 0.075 moles = 0.524 moles [/tex]
[tex]C_{C_{4}H_{7}O_{2}H} = \frac{0.064 moles}{1.30 L} = 0.049 M[/tex]
[tex] C_{C_{4}H_{7}O_{2}^{-}} = \frac{0.524 moles}{1.30 L} = 0.403 M [/tex]
Now, from equation (1) we have:
C₄H₇O₂H(aq) + H₂O(l) ⇄ C₄H₇O₂⁻(aq) + H₃O⁺(aq)
0.049 - x 0.403 + x x
[tex] Ka = \frac{[C_{4}H_{7}O_{2}^{-}][H_{3}O^{+}]}{C_{4}H_{7}O_{2}H} [/tex]
[tex]1.52 \cdot 10^{-5} = \frac{(0.403 + x)x}{0.049 - x}[/tex]
[tex]1.52 \cdot 10^{-5}*(0.049 - x) - (0.403 + x)x = 0[/tex]
By solving the above equation for x we have:
x = 1.85x10⁻⁶ = [H₃O⁺]
So, the concentration of butanoic acid and sodium butanoate is:
[tex][C_{4}H_{7}O_{2}^{-}] = 0.345 + 1.85 \cdot 10^{-6} = 0.345 M[/tex]
[tex][C_{4}H_{7}O_{2}H] = 0.049 - 1.85 \cdot 10^{-6} = 0.049 M[/tex]
Finally, from equation (2) we have:
[tex] pH = pKa + log(\frac{[NaC_{4}H_{7}O_{2}]}{[C_{4}H_{8}O_{2}]}) [/tex]
[tex]pH = -log(1.52 \cdot 10^{-5}) + log(\frac{0.345}{0.049}) = 5.7[/tex]
Therefore, the pH of the solution following the addition of 0.075 moles of NaOH is 5.7.
I hope it helps you!
Which of the following is an example of matter? Question 5 options: A) The air around you B) Your thoughts C) Radio waves D) Heat from a fire
Answer:
the air around you
Explanation:matter is physical like the particles in the air or the oxygen in the air. so rocks, earth the sun, anything you can touch is matter. even gasses.
Identify an element as a metal or a non-metal according to its position in the Periodic
Table
Answer:
Metals on the left of the Periodic Table.
Non-Metals on the top-right, plus Hydrogen.
What kind of reaction is 21,02 → 2H,0 + 0,2
A. Single replacement
B. Double-replacement
C. Decomposition
D. Synthesis
Answer:
I think B
Explanation:
Double - replacement
What are abiotic factors of the ecosystem
Answer:
Abiotic factors are the non-living components of the ecosystem, including its chemical and physical factors.
Hope this helps.
Answer:
Abiotic factors of ecoystem are non-living creatures present on ecosystem.
How many moles of potassium in 73.56g of potassium chlorate (V) (KClO 3 )?
Answer:
Approximately [tex]0.6003\; \rm mol[/tex] formula units.
Explanation:
Formula Mass of KClO₃Look up the relative atomic mass data for [tex]\rm K[/tex], [tex]\rm Cl[/tex], and [tex]\rm O[/tex] on a modern periodic table:
[tex]\rm K[/tex]: [tex]39.908[/tex].[tex]\rm Cl[/tex]: [tex]35.45[/tex].[tex]\rm O[/tex]: [tex]15.999[/tex].The relative atomic mass of an element is numerically equal to the mass (in grams) of one mole of its atoms. For example, the relative atomic mass of [tex]\rm K[/tex] is [tex]39.908[/tex]. Therefore, the mass of one mole of [tex]\rm K\![/tex] atoms should be [tex]39.908\; \rm g[/tex].
Each [tex]\rm KClO_3[/tex] "formula" unit includes one [tex]\rm K[/tex] atom, one [tex]\rm Cl[/tex] atom, and three [tex]\rm O[/tex] atoms. Therefore, one mole of [tex]\rm KClO_3\![/tex] formula units would include:
one mole of [tex]\rm K[/tex] atoms, one mole of [tex]\rm Cl[/tex] atoms, and three moles of [tex]\rm O[/tex] atoms.From the relative atomic mass of these three elements:
The mass of one mole of [tex]\rm K[/tex] atoms would be [tex]39.908\; \rm g[/tex].The mass of one mole of [tex]\rm Cl[/tex] atoms would be [tex]35.45\; \rm g[/tex].The mass of three moles of [tex]\rm O[/tex] atoms would be [tex]3 \times 15.999\; \rm g = 47.997\; \rm g[/tex].Combining these three parts should give the mass of one mole of [tex]\rm KClO_3[/tex] formula units:
[tex]\begin{aligned}& M(\mathrm{KClO_3}) \\ &= 39.908 + 35.45 + 3 \times 15.999 \\ &= 122.545\; \rm g \cdot mol^{-1}\end{aligned}[/tex].
Number of moles of KClO₃ formula units in the sampleThe formula mass of [tex]\rm KClO_3[/tex] is [tex]M(\mathrm{KClO_3}) = 122.545\; \rm g \cdot mol^{-1}[/tex], meaning that the mass of one mole of [tex]\rm KClO_3\![/tex] formula units would be [tex]122.545\; \rm g\![/tex].
The mass of this [tex]\rm KClO_3\!\![/tex] sample is [tex]m(\mathrm{KClO_3}) = 73.56\; \rm g[/tex]. The number of moles of formula [tex]\rm KClO_3\![/tex] units in this sample would be:
[tex]\begin{aligned}n(\mathrm{KClO_3}) &= \frac{m(\mathrm{KClO_3})}{M(\mathrm{KClO_3})} \\ &= \frac{73.56\; \rm g}{122.545\; \rm g \cdot mol^{-1}} \approx 0.6003\; \rm mol\end{aligned}[/tex].
To know the exact number of mole of potassium (K) in 73.56 g of potassium chlorate (v), KClO₃ do the following:
Step 1:Determination of the number of mole in 73.56 g of potassium chlorate (v), KClO₃
Mass of KClO₃ = 73.56 g
Molar mass of KClO₃ = 39 + 35.5 + (16×3)
= 39 + 35.5 + 48
= 122.5 g/mol
Mole of KClO₃ =?[tex]Mole =\frac{mass}{molar mass}\\\\Mol KClO_{3} = \frac{73.56}{122.5}[/tex]
Mole of KClO₃ = 0.6 moleStep 2:Determination of the number of mole of potassium, K in 0.6 mole (i.e 73.56 g) of KClO₃
Considering the molecular formula of potassium chlorate (v), KClO₃, we can see that:
1 mole of KClO₃ contains 1 mole of K.
Therefore, 0.6 mole of KClO₃ will also contain 0.6 mole of K.
Therefore, we can conclude that 73.56 g of KClO₃ contains 0.6 mole of potassium, K.
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percentage of carbon in urea
The percentage of carbon in urea is [CO(NH 2) 2] is 20%
The boiling point of water is 100ºC. The boiling point of acetone is 56ºC. Which statement about distilling a mixture of acetone and water is correct?
Acetone remains in the original container.
Water will vaporize from the mixture before acetone.
Acetone is captured and cooled.
Water is collected as it leaves the mixture.
Answer:
Acetone is captured and cooled.
Explanation:
The boiling point of acetone is lower than that of water, so it will vaporise before water. Then acetone will be captured and cooled to separate it from its mixture with water.
The statement which is correct about distilling a mixture of acetone and water is as follows:
Acetone is captured and cooled.Thus, the correct option is C.
What is Distillation?Distillation may be defined as a procedure that generally involves the conversion of a liquid into a vapor that is eventually condensed back to liquid form. With the help of this process, the separation of components or substances from a liquid mixture by using selective boiling and condensation occurs.
Acetone has the lowest boiling point as compared to water. So, it boils faster than that water and vaporizes before water. After the termination of this process, the acetone will be predominantly captured and cooled to separate it from its mixture with water.
Therefore, the correct option for this question is C.
To learn more about the Boiling point of acetone, refer to the link:
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How does the chemistry of the ocean change in response to high levels of CO2 in the atmosphere?
prepare a dialogue between two friends about development of society .
Answer:
Pls pls pls mark brainliest
what is organic chemistry
Answer:
Organic chemistry
Explanation:
Organic chemistry is part of the chemistry that studies carbon compounds, which also use organic compounds, which have characteristics.
Doing my summer school work right now. Please help me pass I don’t want to take chemistry for the third time.
Answer:
13.B 0.15 M KBr
14.C 1 M C²h⁵OH
15.D 0.1 M C⁶H¹²o⁶
16.A 2 K² SO⁴
17.A 2 M K² SO⁴
18.D 0.028 M KBr
19.A 1 M Nal
20.B 0.1 M AICI³
the first attempt to classify the elements was made by newlands true or false
Answer:
True. An English scientist by the name of John Newlands tried to classify the elements in a unique manner. He first started by arranging all the elements in a ascending order according to their atomic weights.
In the molecule 4H2O2 the number of hydrogen atoms is what
Answer:
Scientists
Explanation:
Scientists because they are the one who makes hypothesis.
for every __sodium ions transported ___postassium ions are transported
Answer:
In fact, in many neurons three sodium ions are transported for every potassium ion; sometimes the ratio is three sodium ions for every two potassium ions, and in a few neurons it is two sodium ions for one potassium ion.
Which of the following elements has a complete outer shell of electrons? A. Iron (Fe) B. Hydrogen (H) C. Neon (Ne) D. Nitrogen (N)
Answer:
The answer is Neon
Answer:
neon
Explanation:
neon has a complete outer 2n shell
HELP PLEASE NAME THESE COMPOUNDS topic of amines and amides please explain you steps so i can do the rest of the problems myself
The attachment shows the diagram of two molecules respectively;
The first molecule in the attachment is known as triethylamine,The functional group is amine Which is - CONH2
And there is a methyl group as an attachment, attached at the third(3) carbon atom,making the compound triethyamine.
The second molecule in the attachment is an example of a secondary amide.
The longest carbon chain is five which pentanamide.
The functional group is amide.
The compoud is named by replacing the suffix - ane in pentane (alkane) to the suffix - amide.
Making the compound pentanamide.
Which feature forms at Earth's surface from the cooling of lava?
O extrusion
fault
O intrusion
unconformity
Extrusion is the feature form at Earth's surface from the cooling of lava.
What are extrusive igneous rocks?They are the ones that originate from a sudden cooling of the incandescent magma when it comes to the surface, which means that there is no time for crystals to form, either partially or totally.
Characteristics of extrusive igneous rocksThese are rocks formed mainly by silicate minerals.Pyroclastics are the product of explosive volcanic eruptions and contain rock fragments of different origins, they can be of many shapes and sizes.Therefore, we can conclude that typical volcanic rocks are formed by the rapid cooling of lava and pyroclastic fragments.
Learn more about extrusive igneous rocks here: https://brainly.com/question/1340933
Answer:
A.
Explanation:
step by step of how to convert fahrenheit and celsius to kelvins -5F to kelvins please and thank you
can someone send me something to get chemistry going ;);)
Answer:
Check out libretexts chemistry
Explanation:
It's basically an online free textbook for lots of subjects
highly recommended
Ok , whenever you wanna study chemistry , listen to music that you love. So each time you have to study chem , you will be excited bc u also wanna hear that music u love. Similarly , for every boring work you do , reward yourself for it. It helps , Im sure.
Thank you XD
You work in the special effects department of a movie studio. You are currently working on a superhero movie where the hero is very strong and
can punch through metal. For the next scene you need to replace a 6 inch by 6 inch square of a metal wall with a different material that will
crumble when the actor hits it. What could you use?
Answer:
either potassium or carbon, most likely carbon
Explanation:
the other two options are denser and more durable, making it harder for the actor to punch through
Polyurethane material is dense and durable, making it difficult for actors to claim themselves.
Why are props used in movies?Props are very important in storytelling. They complement and motivate the character, help the actor feel better than the "role", set the scene, set a specific time, place, and cultural setting, and sometimes the main part of the movie. It can even be the focus.
What material is used as a prop?Polyurethane Plastic: Rigid and Semi-Rigid. Create rigid and semi-rigid props using Polytek® polyurethane casting resin.Polyurethane foam. Polyurethane foam is often used to make lightweight props and ornaments.Polyurethane rubber.Learn more about movies here: https://brainly.com/question/15738857
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Charles is given two electrical conductors – aluminium and graphite. Help him to select one for making an electric wire. Justify your reason.
Answer:
I think the answer is aluminium because both graphite and Al are good conductors of electricity but Al is more ductile than graphite. also pls mark as Brainilest.
Explanation:
Draw the geometric, linkage, and ionization isomers for [CoCl5CN][CN].
Answer:
See explanation
Explanation:
The formation of isomers is common to octahedral complexes. Isomers are different compounds with the same molecular formula but different structural formulas. Isomers have different atom to atom connections. Werner's complexes can display; polymerization, ionization, linkage, geometric and optical isomerism among others.
Isomers of coordination compounds are not easily recognizable and not easily separable in the laboratory.
The geometric, linkage and ionization isomers of the complex given in the question are shown below.
A pharmaceutical company is making a large volume of nitrous oxide (NO). They predict they will be able to make a maximum amount of 4860 grams with the materials they have in stock. From the previous 10 volumes they have made, they know that the percent yield of this reaction is fairly low at 47%. How much will the actual yield be? A. 228 grams B. 2284 grams C. 10340 grams D. 486 grams
Answer:
The answer is "Option B"
Explanation:
From the query, the following knowledge is derived:
Yield in percentage = 47%
Performance of theory = 4860 g
Actual yield Rate =?
The percentage return is defined simply by the ratio between both the real return as well as the conceptual return multiplied by the 100. It's also represented as numerically:
[tex]Rate = \frac{Existing \ Rate} {Theoretical \ Rate} \times 100[/tex]
Now We can obtain the percent yield as followed using the above formula:
[tex]\text{Yield in percentage}= \frac{Actual \ yield \ Rate} {Theorical \ Rate} \times 100[/tex]
[tex]47\% = \frac{Actual \ yield \ Rate}{4860}[/tex]
The value of the Actual yield Rate =[tex]47\% \times 4860[/tex]
[tex]= \frac{47}{100} \times 4860 \\\\ = 2284.2 g[/tex]
The Actual yield Rate= 2284.2 g.
Need help :)….please
Answer:
i think B is correct
Explanation:
Which one of these is most likely to gain electrons and which one is most likely to lose electrons? (And please explain why)
1. Ra (Radium)
2. In (Indium)
3. P (Phosphorus)
4. Te (Tellurium)
5. Br (Bromine)
6. Rb (Rubidium)
Answer:
(I). The most likely to lose electron is Rubidium
(II). The most likely to lose electron is Bromine
Explanation:
Given that,
Radium, Indium, Phosphorus, Tellurium, Bromine and Rubidium
We know that,
Metal :
They atom which to lose electron these is called metal.
When the atom loses the electron then the positive charge come on the atom.
The most likely to lose electron is Rubidium
Non metal :
They atome which is gains electron. It is called non metal.
So, we can say that, the non metal gains electron.
When the atom gains the electron then the negative charge come on the atom.
The most likely to gain electron is Bromine
Hence, This is required answer.
Select the items that describe a chemical property below. Choose THREE correct answers.
1:Heated iron can be hammered into a sword.
2:A handwarmer gets warm when it is opened and exposed to air.
3:Propane ignites to heat a grill.
4:Cotton is dyed red to make a dress.
5:A cylinder in an engine uses gasoline to move pistons.
6:Maple syrup is thicker than water.
Answer:
2:A handwarmer gets warm when it is opened and exposed to air.
3:Propane ignites to heat a grill.
4:Cotton is dyed red to make a dress.
Explanation:
The definition of a chemical property is when a property of characteristic of a substance that is observed during a reaction in which a chemical has been changed
Which of the following statements about a chemical reaction is false? Group of answer choices The phases in a chemical reaction tell us the state of the reactants and the products. An individual coefficient, with no reactant or product, in a balanced equation is meaningless. The subscripts in a balanced equation tell us the number of atoms in a molecule.
Answer:
Option B
Explanation:
Let us go through each of the options individually.
option A.
he phases in a chemical reaction tell us the state of the reactants and the products.
This is true because phases representations such as s, l , g and q tells us the state of the reactants if they are in the solid or liquid or gaseous or aqueous state of matter respectively. So this is not our answer.
option B
An individual coefficient, with no reactant or product, in a balanced equation is meaningless.
This option is correct, because in every reaction, there must be the reactant and product present.
option C
The subscripts in a balanced equation tell us the number of atoms in a molecule.
This is correct. Consider the equation below;
2H₂ + O₂ --> 2H₂O
In the reactant phase, the subscripts tells us that we have just two atoms of oxygen present.
What is the PRECAUTION for an Irritant?