The statement which is true during an exothermic reaction is that is Heat is released. (option B)
Endothermic reactionEndothermic reactions are chemical reactions in which the reactants absorb heat energy from the surroundings to form products substances
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Is nail polish a pure substance or a mixture?
Nail polish is a mixture made up of solvents, polymers, colorants, and additives. It can be physically separated into its different components.
Explanation:Nail polish is a mixture, not a pure substance. It is made up of different components, such as solvents, polymers, colorants, and additives. These components are not chemically bonded together and can be separated from each other.
For example, if you leave a bottle of nail polish open, the solvents will evaporate, leaving behind a dried-up mixture. Additionally, if you mix two different colors of nail polish together, you will create a new mixture with a blend of the two colors. Therefore, nail polish is considered a mixture because it contains multiple substances that can be physically separated.
Nail polish is not a pure substance, but rather a mixture of several substances. A pure substance has a constant composition with fixed ratios of elements, but nail polish consists of a blend of different chemicals including solvents, film formers, resins, and plasticizers. Each of these components contributes to the characteristics of the final product, such as its ability to adhere to the nail, its durability, and its shine.
For instance, the film formers and resins create the hard coating on your nails that lasts for days, while the plasticizers provide flexibility so the polish doesn't chip or crack. Solvents are used to keep the other components in a liquid state so they can be easily applied to the nails. Once the polish is applied, the solvents evaporate, leaving behind the hard, colored film on the nail. This makes nail polish a mixture and not a pure substance.
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Nail polish is a homogeneous mixture, not a pure substance. It comprises many components like nitrocellulose, solvents, coloring agents, and plasticizers, each maintaining its own chemical identity within the mixture.
Explanation:Nail polish is not a pure substance but a homogeneous mixture. A homogeneous mixture is a combination of substances with a uniform composition. In the case of nail polish, it is a mixture of several components including but not limited to nitrocellulose, solvents, coloring agents, and plasticizers. Each of these components maintains its own chemical identity within the mixture; they are not chemically bonded into a new, larger chemical compound, which distinguishes mixtures from pure substances that consist of only one type of matter.
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which kind of energy dose a stretched rubber band have
can someone plz help with This question thxs
An unknown solution has a pH of 2. How would you classify this solution?
A. Acidic
B. basic
C. Neutral
D. There is not enough information to answer this question.
Answer:
The answer is my opinion is A. Acidic.
Explanation:
It is lower than 7 (which is neutral) and lower than 8-14 (basic)
Which of these best describes the particle motion taking place as CO2 gas is exposed to freezing temperatures?
The options in the question are as follows
a. The motion of particles becomes random.
b. The motion of the particles is unchanged.
c. The particles move with more force.
d. The particles decrease in speed.
Answer:
The particles decrease in speed.
Explanation:
In a gas at room temperature, the particles of the gas move at a very high speed and in a random manner. A gas has no definite volume and it is also assumed that there is minimal interaction between gas particles. Recall that temperature is a measure of the average kinetic energy of the particles of a system. As the temperature is decreased and heat is withdrawn as the CO2 approaches freezing temperature, the speed and kinetic energy of the particles decreases and significant interaction between particles is observed. Hence the CO2 particles slow down.
is it convection conduction or radiation "air travels this way" please answer
what element has two electrons in its 4d sub level?
Answer is: zirconium (Zr).
Atomic number of zirconium (Zr) is 40, which means it has 40 protons and 40 electrons.
Electron configuration of zirconium atom:
₄₀Zr 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁶4d²5s².
Zirconium has four valence electrons, it is in group 4 and period 5.
Zirconium is a lustrous, grey-white, strong transition metal.
Examine the false statement.
The alkali earth metals have five valence electrons.
Select the rewording of the statement that is true.
The alkali earth metals have one valence electron.
The alkali earth metals have two valence electrons.
The halogens have five valence electrons.
The alkali metals have five valence electrons.
Answer:
The alkali earth metals have one valence electron.
Explanation:
Alkali earth metals are elements that constitute Group I in the periodic table. These include: lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs) and francium (Fr).
The alkali earth metals are characterised by a outer or valence electron configuration of ns¹.
Li = 2s¹, Na = 3s¹, K = 4s¹, Rb = 5s¹, Cs = 6s¹
Therefore, in their outermost or valence shell these elements have only one electron.
Hence the given statement: that the alkali earth metals have 5 valence electrons is false. Instead it should be reworded as:
The alkali earth metals have one valence electron.
The alkali earth metals, located in the second group of the periodic table, have two valence electrons, not five. So, the true rewording of the given statement should be 'The alkali earth metals have two valence electrons'.
Explanation:The statement that 'The alkali earth metals have five valence electrons' is incorrect. The alkali earth metals, which occupy the second group of the periodic table, actually have two valence electrons. Therefore, the correct rewording of the statement would be 'The alkali earth metals have two valence electrons'.
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An apple has a mass of 297 grams. How many kilograms is this? (Note: You can use the information in the table below to make a conversion factor.)
Answer: 0.297 grams.
Explanation: the conversion factor between kilograms and grams is:
1 kg=1000 g
applying this factor to the given mass of an apple, we have:
[tex]297 grams *\frac{1 kg}{1000 grams}[/tex]
as we can see, we just have to divide by 100 so:
297 grams= 0.297 kg.
The apple has a mass of 0.297 kilograms
HOW TO CONVERT GRAMS TO KILOGRAMS:
Grams and kilograms are both units of measuring mass, however, they are not the same. The conversion factor of grams and kilograms is as follows:1 kilogram = 1000 grams
According to this question, an apple has a mass of 297 grams. This means that:If 1 kilogram = 1000 grams
297 grams = 297 ÷ 1000
= 0.297 kilograms
Therefore, the apple has a mass of 0.297 kg.
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Which type of reaction has the general formula of AB + CD → AD + CB?
Technological design is a main focus in the field of _________.
A. biology B. chemistry C. mathematics D. engineering
Which of the answer choices correctly describes nonmetals?
conduct electricity poorly
used in electronics frequently
conduct heat easily
pulled into wires easily
Caleb wants to find out which type of floor material is best for bouncing tennis balls the highest. Which statement best describes the process he should use?
He should use technological design because he will need to make materials.
He should use scientific investigation because he will need to do an experiment.
He should use technological design because he will need to conduct background research.
He should use scientific investigation because he will need to design a prototype.
Answer:
B. He should use scientific investigation because he will need to do an experiment.
Why was it important to have endothermic and exothermic processes in the building materials of your train?
a.Which engines released thermal energy in an exothermic reaction?
b.Which engines absorbed thermal energy in an endothermic reaction?
Find and report the reduction potentials of lithium, sodium, and potassium.
The electrode potential values of [tex]{\text{L}}{{\text{i}}^ + }[/tex] ,[tex]{\text{N}}{{\text{a}}^ + }[/tex] and [tex]{{\text{K}}^ + }[/tex] are [tex]\boxed{ - 3.045{\text{ V}}}[/tex] , [tex]\boxed{ - {\text{2}}{\text{.714 V}}}[/tex] and [tex]\boxed{ - {\text{2}}{\text{.925 V}}}[/tex]respectively.
Further explanation:
Electrochemical cells are the devices that are used to generate an electric current from the energy released by the spontaneous redox reaction. Redox reactions involve the transfer of electrons between the chemical species by oxidation and reduction process. The oxidation process represents the loss of electrons and reduction process represents the gain of electrons.
In order to determine the standard reduction potential, the electrode is coupled with standard hydrogen electrode as illustrated in the attached image. The SHE acts as anode and the metal electrode acts as the cathode. The value of reduction potential for hydrogen has been assigned as 0.00 V.
The formula to calculate cell potential [tex]\left( {{E_{{\text{cell}}}}} \right)[/tex] of the reaction when the reduction occurs as cathode and oxidation occur at anode is as follows:
[tex]{E_{{\text{cell}}}} = {E_{{\text{cathode}}}} - {E_{{\text{anode}}}}[/tex]
The expression of Nernst equation that relates the reduction potential of a half or full electrochemical cell reaction to the standard electrode potential is given as,
[tex]{E_{{\text{cell}}}} = E_{{\text{cell}}}^\circ - \dfrac{{2.303RT}}{{nF}}\log \dfrac{{\left[ P \right]}}{{\left[ R \right]}}[/tex] ……. (1)
Here,
[tex]{E_{{\text{cell}}}}[/tex] is cell potential.
[tex]E_{{\text{cell}}}^\circ[/tex] is standard cell potential.
[tex]R[/tex] is gas constant and is equal to [tex]8.314{\text{ J/K}} \cdot {\text{mol}}[/tex].
[tex]T[/tex] is temperature.
[tex]n[/tex] denotes the number of moles of electrons transferred in the reaction.
[tex]F[/tex] is Faraday constant and is equal to [tex]95484.56{\text{ C/mol}}[/tex] .
[tex]\left[ P \right][/tex] is the concentration of product.
[tex]\left[ R \right][/tex] is the concentration of reactant.
At standard temperature [tex]25\;^\circ {\text{C}}\left( {298{\text{ K}}} \right)[/tex] the value of [tex]\dfrac{{2.303RT}}{F}[/tex] is equal to [tex]0.0592{\text{ V}}[/tex]. Thus the equation(1) is written as,
[tex]{E_{{\text{cell}}}} = E_{{\text{cell}}}^\circ - \dfrac{{0.0591}}{n}\log \dfrac{{\left[ P \right]}}{{\left[ R \right]}}[/tex] …… (2)
Knowing the concentration of the electrolyte solutions taken in the cathodic compartment and substituting the values in the Nernst equation gives the reduction potential for the half cell.
The electrode potential values of [tex]{\mathbf{L}}{{\mathbf{i}}^{\mathbf{ + }}}[/tex] ,[tex]{\mathbf{N}}{{\mathbf{a}}^{\mathbf{ + }}}[/tex] and [tex]{{\mathbf{K}}^{\mathbf{ + }}}[/tex] are [tex]{\mathbf{ - 3}}{\mathbf{.045 V}}[/tex], [tex]{\mathbf{ - 2}}{\mathbf{.714 V}}[/tex] and [tex]{\mathbf{ - 2}}{\mathbf{.925 V}}[/tex] respectively as determined with respect to standard hydrogen electrode at [tex]{\mathbf{298 K}}[/tex].
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Answer details:
Grade: Senior School
Subject: Chemistry
Chapter: Electrochemistry
Keywords: Electrochemical cells, Redox reactions, Oxidation, reduction, cell potential, half-cell, Nernst equation and Faraday constant.
The reduction potential describes the ease with which electrons are accepted by chemical species.
The term reduction potential is a measure of the ease with which a chemical specie accepts electrons and becomes "reduced". The more negative the reduction potential of a chemical specie, the more difficult it is for that chemical specie to accept electrons and become reduced.
The reduction potentials of lithium, sodium, and potassium are as follows;
Lithium = -3.04 VSodium = -2.71 VPotassium = -2.93 VLearn more: https://brainly.com/question/11969651
Potassium and sodium chloride are similar in charge and they both have the same anion. When comparing sodium chloride (36 g / 100 mL at 0 oC) and potassium chloride, which has a higher solubility at 0 oC?
How many atoms of phosphorus are in 5.40 mol of copper(II) phosphate?
Answer:
There are
4.09
×
10
24
atoms of phosphorus in
3.40 mol
copper(II) phosphate.
Explanation:
The formula unit for copper(II) phosphate is
Cu
3
(PO
4
)
2
. If the formula unit represents 1 mole of copper(II) phosphate , then there are 2 moles of phosphorus per 1 mole copper(II) phosphate formula units.
One mole of atoms =
6.022
×
10
23
atoms
.
During the process of answering this question, we will go from:
mol Cu
3
(PO
4
)
2
→
mol P
→
atoms P
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Mol Cu
3
(PO
4
)
2
to
Mol P
Multiply mol
Cu
3
(PO
4
)
2
by mol ratio between
P
and
Cu
3
(PO
4
)
2
, 2:1.
3.40
mol Cu
3
(PO
4
)
2
×
2
mol P
1
mol Cu
3
(PO
4
)
2
=
6.80 mol P
Mol P
→
Atoms P
Multiply mol
P
by
6.022
×
10
23
atoms/mol
.
6.8
mol P
×
6.022
×
10
23
atoms P
1
mol P
=
4.09
×
10
24
atoms P
rounded to three sig figs
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
You can put all the steps into one equation.
3.40
mol Cu
3
(PO
4
)
2
×
2
mol P
1
mol Cu
3
(PO
4
)
2
×
6.022
×
10
23
atoms P
1
mol P
=
4.09
×
10
24
atoms P
In 5.40 moles of copper(II) phosphate, there are 6.50 x 1024 atoms of phosphorus.
Explanation:The number of atoms in a certain amount of a substance can be determined using Avogadro's number, which is 6.022 x 1023 atoms/mole. First, we need to determine the mole ratio between phosphorus and copper(II) phosphate. The formula for copper(II) phosphate is Cu3(PO4)2, meaning each molecule contains two phosphorus atoms. Therefore, in 5.40 moles of copper(II) phosphate, there are 2 times 5.40, or 10.80 moles of phosphorus. To find the number of atoms, we multiply the number of moles by Avogadro's number: 10.80 moles x 6.022 x 1023 atoms/mole = 6.50 x 1024 phosphorus atoms.
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is NaCH an element ? why or why not?
A neutral atom of beryllium (Be) has an average mass of 9 amu and 4 electrons. How many neutrons does it have?
13
9
5
4
To find the number of electrons, just subtract the amu and the atomic number (aka number of protons or electrons)...
so it is...
9-4=5 neutrons
Brainliest plz! :)
The number of neutrons in a neutral atom of beryllium is equal to 5. Therefore, option (B) is correct.
What is a neutral atom?A neutral atom can be defined as an atom in which the number of the negative charge is equal to the number of the positive charge. Therefore, the overall electric charge on the neutral atom is zero.
We can say that for a neutral atom, the number of protons in an atom is equal to the number of electrons in that atom. All elements arranged in the modern periodic table are in a neutral state.
The atomic mass or average mass of the atom is the sum of the number of protons and neutrons in the nucleus of that atom.
Given, the average mass of beryllium (Be) atom = 9 amu
Therefore, protons + neutrons = 9 in the one Be atom
The number of electrons in Be atom = 4
The number of neutrons in netural beryllium atom = 9 - 4 = 5
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humans protect themselves from natural disasters by all of the following expect ?
a. dams
b. sunscreen
c. building homes and shelters
d. levees
After a hormone enters the bloodstream, it is transported throughout the body, but the hormone only affects certain cells. The reason only certain cells are affected is that the membranes of these cells have specific
Final answer:
Only certain cells are affected by hormones because these cells have specific receptor proteins that allow the hormone to bind and initiate a response. These receptors determine the cell's sensitivity to the hormone and can vary through up-regulation or down-regulation, adapting to hormone levels.
Explanation:
The reason only certain cells are affected by hormones is because only some cells have receptor proteins that can bind to a given hormone. These receptors are specific to a particular hormone and allow it to have an effect when it binds to them.
The hormone will travel throughout the bloodstream until it finds a cell with the correct receptor and binds to it, which initiates various responses depending on the type of hormone, such as a steroid hormone or a non-steroid hormone.
Hormones, acting as messengers, are crucial in regulating physiological processes. They play a significant role in human reproduction, development, metabolism, and maintaining homeostasis, among other functions.
The presence and quantity of hormone receptors determine which cells will respond to a given hormone, thus determining the sensitivity of the cell to the hormone. Cell sensitivity to hormones can change through processes like up-regulation and down-regulation, which adapt the number of receptors available in response to hormonal levels.
Hydrogen peroxide is sold as a 3.0% (by mass) solution. The rest of the solution is water . How many grams of hydrogen peroxide are in 250 grams of this solution?
The question deals with percent by mass calculations. For a 3.0% by mass solution of hydrogen peroxide, there are 3 grams of hydrogen peroxide in every 100 grams of the solution. Therefore, a 250-gram solution would contain 7.5 grams of hydrogen peroxide.
Explanation:The solution of hydrogen peroxide is 3.0% by mass. This means that there are 3 grams of hydrogen peroxide in every 100 grams of solution. Therefore, in 250 grams of solution, the amount of hydrogen peroxide can be calculated by setting up a proportional equation:
(3 grams H2O2 / 100 grams solution) = X grams H2O2 / 250 grams solution
To solve for X, which represents the amount of hydrogen peroxide, cross multiply and divide:
(3 g H2O2 x 250 g solution) / 100 g solution = 7.5 g H2O2
So, there are 7.5 grams of hydrogen peroxide in a 250-gram solution.
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Describe the preparation of 2.00 L of 0.100 M glycine buffer, pH 9.0, from glycine and 1.00 M NaOH.
Which of the following is a reasonable ground-state electron configuration?
a. 1s2 1p6 2s2 2p6 3s2
b. 1s2 2s2 2p6 3s2 3p6 4s2 4d8
c. 1s2 2s2 2p6 3p6
d. 1s1 2s2 2p6 3s1
Answer:
b) 1s2 2s2 2p6 3s2 3p6 4s2 4d8
Explanation:
Electron configuration of an atom is given based on the Aufbau principle which states that electrons are arranged in orbitals such that the lower energy orbitals are filled first. The increasing energy order of orbitals is:
1s < 2s < 2p < 3s < 3p < 4s < 3d < 4p....
s, p ,d orbitals can accommodate a maximum of 2,6 and 8 electrons respectively.
Based on the above ordering, the most reasonable ground state configuration would be:
1s2 2s2 2p6 3s2 3p6 4s2 4d8
Is rust a pure substance or a mixture? <3
Rust is considered a mixture, not a pure substance, because its composition can vary. It is formed when iron reacts with oxygen and water.
Explanation:Rust is not a pure substance, it is a mixture. In scientific terms, rust is formally known as iron (III) oxide and is formed when iron reacts with oxygen and water. In this case, it behaves as a mixture because its composition can vary depending on the presence and relative abundance of other elements and compounds, such as water and other oxides.
Rust is a mixture rather than a pure substance. It is formed when iron reacts with oxygen in the presence of water or moisture, resulting in the formation of iron oxide, which is the reddish-brown substance we commonly refer to as rust. This mixture consists of iron oxide as well as other impurities, such as traces of water and other metals present in the environment.
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How many grams of oxygen are formed when 8.20 moles of KOH are formed? 4 KO(s) + 2 H2O(l) → 4 KOH(s) + O2(g)
Answer : The mass of oxygen formed are 65.6 grams.
Explanation :
First we have to calculate the moles of [tex]O_2[/tex]
The given balance chemical reaction is:
[tex]4KO(s)+2H_2O(l)rightarrow 4KOH(s)+O_2(g)[/tex]
From the balanced chemical reaction we conclude that,
As, when 4 moles of KOH formed then 1 mole of [tex]O_2[/tex] will be formed
So, when 8.20 moles of KOH formed then [tex]\frac{8.20}{4}=2.05[/tex] mole of [tex]O_2[/tex] will be formed
Now we have to calculate the mass of [tex]O_2[/tex]
[tex]\text{ Mass of }O_2=\text{ Moles of }O_2\times \text{ Molar mass of }O_2[/tex]
Molar mass of [tex]O_2[/tex] = 32 g/mole
[tex]\text{ Mass of }O_2=(2.05moles)\times (32g/mole)=65.6g[/tex]
Therefore, the mass of oxygen formed are 65.6 grams.
what do animal cells need in order to maintain homeostasis A. light energy B. carbon dioxide C. chemical energy D.carbon monoxide
How do the cells of a multicellular organism differ from those of a unicellular organism
Answer:
The cells of unicellular organism is not equipped for different function which means that it do not have different types of cells differentiated into different types performing different functions.
They are made of single cells that perform all the essential functions necessary for survival of organism.
Whereas, a multicellular organism have different types of cells that are employed for different functions.
Example:The hepatocytes are equipped for filtering blood and waste removal. The red blood cells are equipped to transport oxygen to various parts of the body.
How will the following system react when an increase in pressure occurs? Note: all species are gases. N2O4 <--> 2NO2 Question 9 options:
a. More N2O4 is produced.
b. There is no way to predict how the increase in pressure will affect this system without more information.
c.No change occurs.
d.More NO2 is produced.
a is incorrect just took the test
Scientists have established that some of the layers of Earth are solid, some are liquid, and some are semi-fluid. Explain how the scientists are able to determine the liquid and solid layers. Use at least two pieces of evidence to support your answer.
Answer: Several studies has been made in order to understand the layers of the earth. Some of the evidences that proved the existence of solid and liquid layers are as follows-
According to the concept of Isostacy, the earth's crust is a like a solid wooden block, that floats over a vast liquid which is compared here with the mantle. Due to the variation in the crustal density, the crust sinks or gets uplifted.From the geophysical point of view, the study of the seismic waves made clear that the earth is comprised of three distinct layers such as the crust, mantle and the core. Crust refers to to top layer, mantle is the middle part and core is the interior part of the earth which is divided into two types, inner core (solid in nature) and outer core (liquid in nature).Enter the net ionic equation, including phases, for the reaction of AgNO3(aq) with K2SO4(aq). Solubility Rules are found here.