Answer:
because in the different countries it is distributed unevenly.
Explanation:
hope this helps
Chemical that can be mixed with another chemical to reduce the dangerous of a specific chemical
Answer:
Chemical that can be mixed with another chemical to reduce the dangerous of a specific chemichal
A train travels with a constant speed of 72 miles per hour. How long will it take to travel a distance of 126 miles?
Answer:
it takes the train 1 hour and 75 minutes
Explanation:
you multiply the constant speed starting from 1 (which represents 1 hour) then you add as many decimal places as you need. Bit of a confusing explanation
What happens when a dendritic cell detects a pathogen?
the dendritic cell will cause agglutination of the pathogen cells
the dendritic cell consumes the pathogen by phagocytosis...
the dendritic cell secretes antibodies
the dendritic cell will produce immunoglobin
Answer:
the dendritic cell consumes the pathogen by phagocytosis
how grignard reagent is dependent upon the nature of R?
Explanation:
Haloalkanes and other compounds with the halogen atom bonded to either sp3-hybridized or sp2-hybridized carbon atoms (aryl and vinyl halides) react with magnesium metal to yield organomagnesium halides called Grignard reagents. Grignard reagents are usually prepared in diethyl ether (CH3CH2O─CH2CH3). An ether solvent is essential for the reaction. The French chemist Victor Grignard discovered this reaction in 1900, and it has been studied and used extensively ever since.
Grignard reagents form easily from 1°, 2°, and 3° alkyl halides, although their reactivities differ. Aryl and vinyl halides react somewhat more slowly, and the cyclic ether tetrahydrofuran (THF) is required to prepare Grignard reagents of these compounds. The higher boiling point of the cyclic ether provides more vigorous reaction conditions, but the rate of the reaction also increases because THF solvates the Grignard reagent better than diethyl ether.
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Molecular model of a complex of methyl-magnesium chloride, a Grignard reagent, in which two molecules of tetrahydrofuran, THF, are bound to magnesium. The model is based on the crystal structure.
The order of reactivity of the halogens in haloalkanes is I > Br > CI > > F. Organofluorides are so unreactive that they are never used to prepare Grignard reagents. Organohalogen compounds containing bromine and chlorine are readily available, and are commonly used to prepare Grignard reagents. Grignard reagents are used synthetically to form new carbon–carbon bonds. A Grignard reagent has a very polar carbon–magnesium bond in which the carbon atom has a partial negative charge and the metal a partial positive charge.
The polarity of the carbon–magnesium bond is opposite that of the carbon–halogen bond of haloalkanes. Because the carbon atom in a Grignard reagent has a partial negative charge, it resembles a carbanion, and it reacts with electrophilic centers such as the carbonyl carbon atom of aldehydes, ketones, and esters. We will discuss this chemistry extensively in later chapters.
Grignard reagents react rapidly with acidic hydrogen atoms in molecules such as alcohols and water. When a Grignard reagent reacts with water, a proton replaces the halogen, and the product is an alkane. The Grignard reagent therefore provides a pathway for converting a haloalkane to an alkane in two steps.
formula of sodium chloride, sodium trioxocarbonate (IV), aluminum oxide, ammonium sulphide, zinc hydroxide, zinc tetraoxosulphate (IV), sodium tetraoxosulphate (VI), trioxonitrate (V) acid, water
Answer:
The correct answer is Na2CO3. 10H2O
While on the scene of a very large explosion, you realize that you and your colleagues require additional wire mesh screens to collect evidence. What are you most likely sifting through?
A. Liquid found at the crime scene
B. Debris found at the crime scene
C. Dirt from footprints found at the crime scene
D. Vapors from the explosion
The individual is most likely sifting through the debris which is found at the crime scene.
What is Debris?This is defined as the scattered remains of something which has been broken down as a result of incidents such as an explosion.
The wire mesh is used as it helps to remove long fibers present at the crime scene which is taken for investigation.
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me need help...................!!!!!!!!!!!
Answer:
Explanation:
As the distance to the outermost electron of the Group 1 element increases, the amount of energy required to remove an electron decreases.
That's D
A: and C: are both incorrect for the same reason. Group 1 elements don't add electrons -- they try and give those electrons away.
B: all of the group one have only 1 valence electron,
A 240.0 gram piece of copper is dropped into 400.0 grams of water at 24.0 °C. If the final temperature of water is 42.0 °C, what was the initial temperature of the copper piece? (5 points)
Specific heat of copper = 0.39 J/g °C
Group of answer choices
322 °C
345 °C
356 °C
364 °C
The initial temperature of the copper piece if a 240.0 gram piece of copper is dropped into 400.0 grams of water at 24.0 °C is 345.5°C
How to calculate temperature?The initial temperature of the copper metal can be calculated using the following formula on calorimetry:
Q = mc∆T
mc∆T (water) = - mc∆T (metal)
Where;
m = massc = specific heat capacity∆T = change in temperatureAccording to this question, a 240.0 gram piece of copper is dropped into 400.0 grams of water at 24.0 °C. If the final temperature of water is 42.0 °C, the initial temperature of the copper is as follows:
400 × 4.18 × (42°C - 24°C) = 240 × 0.39 × (T - 24°C)
30,096 = 93.6T - 2246.4
93.6T = 32342.4
T = 345.5°C
Therefore, the initial temperature of the copper piece if a 240.0 gram piece of copper is dropped into 400.0 grams of water at 24.0 °C is 345.5°C.
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Answer:
the correct answer is 364
q = m * c * ΔT
where q is the heat absorbed or released, m is the mass of the substance, c is the specific heat capacity of the substance, and ΔT is the change in temperature.
We can assume that the heat lost by the copper is gained by the water, so:
q(copper) = -q(water)
where the negative sign indicates that the copper loses heat while the water gains heat.
The specific heat capacity of copper is 0.39 J/g °C, so:
q(copper) = 240.0 g * 0.39 J/g °C * (T(copper) - 24.0 °C)
The specific heat capacity of water is 4.18 J/g °C, so:
q(water) = 400.0 g * 4.18 J/g °C * (42.0 °C - T(copper))
Setting q(copper) equal to -q(water), we get:
240.0 g * 0.39 J/g °C * (T(copper) - 24.0 °C) = -400.0 g * 4.18 J/g °C * (T(copper) - 42.0 °C)
Simplifying and solving for T(copper), we get:
T(copper) = [(400.0 g * 4.18 J/g °C * 42.0 °C) + (240.0 g * 0.39 J/g °C * 24.0 °C)] / (240.0 g * 0.39 J/g °C + 400.0 g * 4.18 J/g °C)
T(copper) = 364.1 °C
Therefore, the initial temperature of the copper piece was 364.1 °C.
Hence, the answer is "364 °C".
If 25.0 g NO are produced, how many grams of nitrogen gas are used?
A: 5.84 g
B: 11.7 g
C: 23.3 g
D: 33.6 g
Using the stoichiometry of the reaction and the information provided in the question, the mass of N2 used is 11.62 g.
Chemical reactionThe term chemical reaction refers to the combiantion of two or substances to yiled one or more products. The reaction equation in this case is N2 + O2 --->2NO.
Now;
Number of moles of NO = 25g/30 g/mol = 0.83 moles
1 mole of N2 yields 2 moles of NO
x moles of N2 yileds 0.83 moles of NO
x = 0.415 moles
Mass of N2 = 0.415 moles * 28 g/mol = 11.62 g
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Please help with this answer!
[tex]\qquad\qquad\huge\underline{{\sf Answer}}♨[/tex]
The Correct choice is : D
if temperature is held constant, then they have same average kinetic Energy because there's no change in energy caused by transfer of heat or something.
According to the forces of attraction, if temperature is constant the particles have the same average kinetic energy.
What are forces of attraction?Forces of attraction is defined as a force by means of which atoms in a molecule combine. it is basically an attractive force in nature. It can act between an ion and an atom as well.It varies for different states of matter that is solids, liquids and gases.
The forces of attraction are maximum in solids as the molecules present in solid are tightly held while it is minimum in case of gases as the molecules are far apart . The forces of attraction in liquids is intermediate of solids and gases.
The physical properties such as the melting point, boiling point, density are all dependent on forces of attraction which exists in the substances.
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the reaction between calcium carbonate and hydrochloric acid which two of the products contain oxygen
Calcium carbonate (CaCO3) is a metal carbonate compound and reacts with hydrochloric acid (HCl) to produce carbon dioxide (CO2), calcium chloride (CaCl2) and water. You can see, carbon dioxide gas is released through the solution.
calcium carbonate and hydrochloric acid reaction
CaCO3 + HCl → CaCl2 + CO2 + H2O
How do I know the numerical subscript of an element? for example CuCl 2
Cu is copper (II), how do we know its roman number is 3
Answer:
"The Roman numeral denotes the charge and the oxidation state of the transition metal ion. For example, iron can form two common ions, Fe2+ and Fe3+. To distinguish the difference, Fe2+ would be named iron (II) and Fe3+ would be named iron (III)."
Explanation:
In chemistry, Roman numerals are used for a specific group of elements called transition metals. The Roman numerals indicate the charges that these metals carry in a compound.
The microscopes used today are just like the ones used by Leeuwenhoek and Hooke. True or false
Answer:
False
Explanation:
While we do know that A. Leeuwenhoek used a simple microscope that consisted of only 1 lens, Hooke used a compound microscope. Although, after trying a compound microscope, Hooke found out that it strained his eyes and continued to use a simple microscope for his Micrographia.
Thus, we can say that the (compound) microscopes used today are different than the (simple) microscope used by Hooke and Leeuwenhoek.
Ivana is studying insect life cycles. She placed a male and a female gnat inside a terrarium. The female gnat laid eggs. Ivana observed and recorded all of the stages she saw the eggs go through. Her results are shown in the table below.
Answer:
B. A gnat completes its life cycle in about 1 month.
Explanation:
Stage Time in Stage
egg 24 hours
larva 7 days
pupa 6 days
adult 2 weeks
Which of the following is a valid conclusion that Ivana can draw from her data?
A. Agnat generally does not live for more than 1 week.
B. Agnat completes its life cycle in about 1 month.
C. Agnat life cycle has more than five stages.
D. Agnat is a crustacean, not an insect.
Pregnant women are often cautioned against cleaning cat litter boxes. This is because Toxoplasma, an intestinal parasite of cats, can be transmitted from infected feces to the expectant mother and ultimately to the fetus. For these reasons, Toxoplasma is considered
....
a noninfectious disease.
a communicable disease.
an addictive disease.
a nosocomial disease.
a zoonotic disease.
a necrotizing disease..
Answer:
A communicable disease
Explanation:
Diseases that can be transferred are known as communicable diseases.
Explain the following a. the mole of a substance. b.a standard solution
a. the mole of substance
b.a standard solution
in analytical chemistry standard solution is a solution containing a precisely known concentration of an element or a substance.
A known mass of solute is dissolved to make a specific volume. it is prepared using a standard solution,such as a primary standard.
hope this helps you
When one mole of hydrogen, H2, is formed, 131 kJ of energy is absorbed.
Calculate the amount of energy absorbed when 240 dm3 of hydrogen, measured at room temperature and pressure, is formed
the amount of energy absorbed when 240 dm3 of hydrogen, measured at room temperature and pressure, is formed.
solution:According to Avogadro's law 1 mole of any gas occupies 22.4 L (dm3) at room temperature and pressure.
So the amount of energy absorbed:
(kJ)E=131∗240/22.4
=1403.6(kJ)
1403.6 kJ is absorbed when 240 dm3 of hydrogen, measured at room temperature and pressure is formed.
what is the advantege of relase energy in a chemica reaction
Answer:
A chemical reaction can release chemical energy stored in batteries, natural gas, and even coal. The main advantage of chemical energy is that it is abundant in nature. Chemical energy can be produced by many organic materials.
Hope this helps!!!!!!
Mark Brainleast!!!!!!!!!!!!
If I have 21 moles of gas held at a pressure of 78 atm and a temperature of 901 K, what is the volume of the gas?
n this questions certain
a
r
e
g
i
v
e
n
,
of moles ,n = 21 mol, Pressure P = 78 atm, Temperature T = 900 K, Volume V = ?
We have to calculate the volume of the given moles of gas at specific temperature and pressure.
Using Ideal Gas equation;
PV = nRT
V = nRT /P ( R = gas constant = 0.08206 L atm
m
o
l
−
1
K
−
1
)
V= 21 mol x 0.08206 L atm
m
o
l
−
1
K
−
1
x 900K / 78 atm
V= 73.854 L atm / 78 atm = 0.946 L
help help help help help
Answer:
It's C.
Explanation:
According to the site, "http://needtoknow.nas.edu/energy/energy-sources/renewable-sources/wind/" ... "Wind energy is an indirect form of solar energy created by a combination of factors, including the uneven heating of Earth’s atmosphere by solar radiation, variations in topography, and the rotation of Earth. People have been putting wind energy to use throughout history to propel sail boats, mill flour from grain, and pump water."
Which best describes the forces in the nucleus of a stable atom?
O A. The weak nuclear force is greater than the electrostatic force.
O B. The electrostatic force is greater than the strong nuclear force.
O c. The weak nuclear force balances out the strong nuclear force.
O D. The strong nuclèar force balances out the electrostatic force.
Best describes the forces in the nucleus of a stable atom is the strong nuclear force balances out the electrostatic force.
The center region of an atom, which is composed of two different types of particles, is known as the atomic nucleus. Protons with positive charges and neutrons with no charges are present. Because of the strong electrostatic attraction between positively charged protons, atomic nuclei should be unstable, however they occasionally remain stable for more than a billion years.
The stability of nuclei suggests that protons and neutrons are attracted to one another by an attractive force. The strong nuclear force, also known as the residual strong force, is responsible for every individual atomic nucleus' stability. Neutrons and protons are held together by this basic force of nature. It is used to explain the atom's and its nucleus' stability, which is otherwise puzzling. It can be used to explain the origin of all atoms and, consequently, the origin of all known simple and complex molecules.
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Identify any three ways of conserving and managing forest in nepal.
Answer:
We should manage and conserve forest resources in Nepal.
Explanation:
Nepal is the second richest country in natural resources. We should all work together and conserve our natural resources. We can conserve and manage forests in Nepal by the following ways:
1. Proper rules and laws should be made as well as executed by our government.
2. Illegal activities regarding harm of forests and its resources should be totally band.
3. Awareness programmes should be conducted worldwide to aware our citizens regarding conservation of forests.
with a given number of moles of solvent,the solution will always have the same concentration. T or F please explain why.
Answer:
Its False
Explanation:
Its False because the concentartion would have to be the solute the thing being added. BUT if you add the equal amount of solvent and add more solute than the one you added more solute is the more concentarted.
AN EXAMPLE:
An example we have Cup A and Cup B we add the same amount of water to both cups but i add more solute to cup A (Examples of solute Salt,powder) and i add less solute to b I balance them in a balance. and cup A is the most concentrated because It has more solute.
ANOTHER EXAMPLE:
Lets do the same thing i add the same amount of water to cup A and B I want to add the same solute but i cant since Cup A saturates At 8 Spoons And B at 6 So cup A is most concentared
Conclusion:
So it all depends on the solute how much you add or at how many spoons you saturate.
Thats all I hope it helped!!
The concentration of the solution depends upon the number of moles of solute with changing, the concentration will change. Therefore, the given statement is false.
What is the molar concentration?The concentration of the given solution can be determined in the terms of molarity, Normality, and molality. We can easily calculate the molar concentration of a substance in a solution.
In chemistry, concentration can be described as the abundance of a constituent divided by the total volume of a mixture. The concentration can be mass concentration, number concentration, molar concentration, and volume concentration.
The concentration of the solution determined as the number of moles of a solute per unit volume of a solution is known as molarity or molar concentration.
The Molar concentration of a solution is evaluated in the following way.
Molarity (M) of the solution = Moles of solute/Volume of the Solution
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4. How does the sun release its heat?
Answer:
radiation i think
Explanation:
thts why the solar panels can maķe electricity
Please help!!! This is due later today and I have no idea how to do this
Answer:
If you have a periodic table of the elements, you should be able to do this easily. The best periodic table, in my opinion, is the interactive periodic table at ptable(.com).
I will attach a formula sheet with everything you might need to know in chemistry.
Explanation:
You should be able to do this, but if you need more help let me know! :)
what are the products for the following equation?
LiBr + F ->
[tex]\qquad\qquad\huge\underline{{\sf Answer}}♨[/tex]
Here's the balanced chemical equation for above reaction ~
[tex]\qquad \sf \:LiBr + F \rightarrow Li F + Br[/tex]
Here, fluorine is more more more reactive than Bromine, therefore it replaces Bromine from its compound and forms Lithium floride.
Proteins are biological polymers made of ?
Answer:
amino acids
Explanation:
Proteins are polymers made from different monomers, called amino acids.
Hope this helps.
What is the pH of a solution that has a poH of 1.8?
Answer:
Ok so To calculate the pH of an aqueous solution you need to know the concentration of the hydronium ion in moles per liter (molarity). The pH is then calculated using the expression:
pH = - log [H3O+].
Example: Find the pH of a 0.0025 M HCl solution. The HCl is a strong acid and is 100% ionized in water. The hydronium ion concentration is 0.0025 M. Thus:
pH = - log (0.0025) = - ( - 2.60) = 2.60
Explanation:
The hydronium ion concentration can be found from the pH by the reverse of the mathematical operation employed to find the pH.
[H3O+] = 10-pH or [H3O+] = antilog (- pH)
Example: What is the hydronium ion concentration in a solution that has a pH of 8.34?
8.34 = - log [H3O+]
- 8.34 = log [H3O+]
[H3O+] = 10-8.34 = 4.57 x 10-9 M
On a calculator, calculate 10-8.34, or "inverse" log ( - 8.34).
QUESTION 4 An aqueous solution of 4 mol/L nitric acid is electrolyzed in an electrolytic cell using graphite electrodes.
a) Write the chemical symbols for all the ions present in the electrolytic cell. (1 mark]
b) Name the gas given off at the cathode. [1 mark]
c) Name the gas given off at the anode. [1 mark]
d) Write the half reaction equations at the;
i) Cathode : [1 mark)
ii) Anode : [1 mark]
e) The overall anode - cathode reaction equation taking place in the electrolytic cell. [1 mark]
The gas given off at the cathode is hydrogen while the gas given off at the anode is oxygen.
What is electrolysis?The term electrolysis has to do with the decomposition of a substance by the passage of direct current through it.
The ions present in the system are H^+, OH^- and NO3^- ions. The gas given off at the cathode is hydrogen while the gas given off at the anode is oxygen.
The half reaction equation of the reduction is;
2H^+(aq) + e ----->H2(g)
The oxidation half reaction equation is;
4OH^- (aq)------> 2H2O(l) + 4e
The overall equation is;
4H^+(aq) + 4OH^- (aq)------> 4H2(g) + 2H2O(l) + 4e
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Describe the three possible decisions you can receive from an
editor when you submit a scientific article for publication. Which
decision is the least likely to occur?
a
Your answer should consist of 3-4 complete sentences with
correct grammar/spelling/punctuation.
Answer 2. Accept with minor revisions: Also known as conditional acceptance, this decision means that the paper requires minor changes for it to be ...
wer:
Explanation:
