The reaction is endothermic because the temperature dropped from 28 degrees Celsius to 20 degrees Celsius.
Meaning of endothermic and exothermic reaction:An endothermic reaction is one in which heat is absorbed from the surrounding resulting in decrease in temperature while an exothermic reaction is one in which heat is evolved causing the temperature to rise.
In the particular context of this question, the reaction is endothermic because the temperature dropped from 28 degrees Celsius to 20 degrees Celsius. The heat in the surroundings decreased.
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how many pounds of gold are present in 1 cubic mile of seawater?
Answer:
38 pounds of gold in cubic mile of seawater.
1. In drawing Lewis structures, a single line (single bond) between two elements represents: ? a shared electron B. ? B 2 a shared pair of electrons c. ? an octet of electrons D. ? an unshared pair of electrons
Answer:
B a shared pair of electrons (2)
Explanation:
In Lewis structures, a single line represents a single pair of electrons. This means that the elements share 2 electrons or one pair of electrons
Hope this helps!
The shared electrons behave as if they belong to both atoms in the bond and bind the two atoms together to form a molecule. The shared electrons are typically depicted as a line (—) connecting the bonded atoms. (A line in a Lewis structure represents two electrons. Therefore, option A is correct.
What is lewis structure ?Lewis structures, also known as Lewis dot formulas, Lewis dot structures, electron dot structures, or Lewis electron dot structures, are diagrams that depict the bonding between atoms in a molecule as well as any lone pairs of electrons that may exist.
A Lewis structure is based on the octet rule, which states that atoms share electrons in order for each atom to have eight electrons in its outer shell. An oxygen atom, for example, has six electrons in its outer shell.
Gilbert N. Lewis, who introduced the Lewis structure in his 1916 article The Atom and the Molecule, was named after it. Lewis structures expand on the electron dot diagram concept by adding lines between atoms to represent shared pairs.
Thus, option A is correct.
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How is the polarity of a bond different from the polarity of a molecule?
Answer:
A polar bond is one where the charge distribution between the two atoms in the bond is unequal. A polar molecule is one where the charge distribution around the molecule is not symmetric. It results from having polar bonds and also a molecular structure where the bond polarities do not cancel.
Explanation:
Melting gold with other metals makes 10 karat gold. Which term best describes 10 karat gold
The 10 karat of gold formed by melting gold with other metals is described as homogeneous mixture.
A pure substance is a substance that is made up of only one kind of particle. This type of substance consist of only one element.
A heterogeneous substance is a type of substance that is made up two or more substances existing in different phases.
A homogeneous substance is a type of substance that is made up of two or more substances evenly mixed. This type of substance exist only in one phase.
Thus, the 10 karat of gold formed by melting gold with other metals is described as homogeneous mixture.
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Answer:
homogeneous mixture
Explanation:
What is the enthalpy of reaction for the decomposition of calcium carbonate? CaCO3(s) Right arrow. CaO(s) CO2(g) kJ.
The enthalpy of reaction for the decomposition of calcium carbonate is 177.4 KJ/mole .
We know that the enthalpy of reaction can be obtained from the enthalpy of formation of the reactants and that of the products using the formula;
ΔHrxn = ΔHf (products) - ΔHf (reactants)
The heat of formation of the species are as follows;
ΔHf (CaCO3(s)) = −1206.9 KJ/mol
ΔHf (CaO(s)) = - 636 KJ/mole
ΔHf (CO2(g)) = -393.5 KJ/mole
ΔHrxn = [( -393.5 KJ/mole ) + ( - 636 KJ/mole)] - [ −1206.9 KJ/mol]
ΔHrxn = 177.4 KJ/mole
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Answer:
First one is 656.3 and second is endothermic.
Explanation:
Edge Thermochemical Equations assignment
preventive maintenance on a hot water heater includes:
A water heater can be regularly maintained by flushing it at least two times in a year.
A water heater is a device that is used to heat up water for home use. There are different types of water heaters but they all serve the same purpose at home. In order to maintain maximum efficiency, the water heater must be maintained regularly.
The following are routine maintenance operations on a water heater;
Inspect the heater regularly to ascertain if there are faults.Flush the heater at least two times each year.The anode rod should be changed after a couple of yearsLearn more about water heater;https://brainly.com/question/4751630
225 million km to seconds
Answer:
You can't convert km to seconds because they are different units.
P 1. Elements X and Y react to form an ionic compound a formula XY. What could be the proton (atomic) numbers of X and Y?
X | Y
A | 3 | 8
B | 6 | 8
C | 8 | 16
D | 12 | 16
Answer:
the answer is C
Explanation:
This is because group6 elements are diatomic and when they are chemically combined their subscript 2 cancels out
4. Public water supplies are unsafe in some parts of the world because the water
and
may carry
Answer:
In many parts of the world, water taken directly from wells or public supplies is not safe to drink because it may carry waterborne parasites or other diseases. The water can be sterilized by boiling it, but fuel is needed to do so.
Explanation:
Answer: Public water supplies are unsafe in some parts of the world because the water may carry bacteria.
Explanation:
During an investigation, a student mixes two liquids in a beaker. The student recorded the following observations in her science notebook.
I. Both liquids are clear prior to mixing.
II. Both liquids are room temperature prior to mixing.
III. The liquid turned pink when mixed.
IV. The temperature of the liquid increased.
V. Over time, a white solid formed at the bottom of the beaker.
Required:
What are evidence of a chemical reaction?
Answer:
3, why because most of the time chemicals reacts within eachother to make new compound that's may lead the liquid chemicals to deflect some of the spectrom of light like red,yellow,blue
To solve such this we must know the concept of chemical reaction. There are so many ways to identify the chemical reaction. Therefore the correct options are option 3, 5.
What is chemical reaction?Chemical reaction is a process in which two or more than two molecules collide in right orientation and energy to form a new chemical compound. The mass of the overall reaction should be conserved that is mass can nether be created nor be destroyed in a chemical reaction.
There are so many types of chemical reaction reaction like combination reaction, double displacement reaction. The evidence of a chemical reaction are "the liquid turned pink when mixed" and "over time, a white solid formed at the bottom of the beaker".
Therefore the correct options are option 3, 5.
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The more impressive the tail of a male peacock, the higher its chances of finding a mate. Female peacocks choose mates based on the color of the feathers and the overall physical prowess of the animal. However, a genetic mutation called leucism can produce a peacock with only white feathers. This mutation causes the inability of pigment to be deposited into their feathers which results in a white appearance. What would you infer to be the fitness of the white peacock? Choose ALL that apply.
A) The females will equally choose the brightly colored and white peacocks as mates.
B) White peacocks are highly prized, thought to symbolize purity, eternity, and unconditional love, making them desirable mates.
C) If females choose the brightest males as partners, the ones without the impressive tails will be less likely to mate and reproduce.
D) White peacocks are highly prized, thought to symbolize purity, eternity, and unconditional love, causing them to be selectively bred for their unique trait.
E) The peacocks with colored tails will be picked over the white peacocks as mates, causing the peacocks with the white mutation to die out of the population over time
Leucism is a genetic mutation caused by an alteration of a nucleotide. The less brightly colored tails of the peacock will have less chance to mate.
What is selection?Selection is the natural process in which the organism with better trait quality is preferred and selected over another species. They are fit to survive in an altered condition.
The genetic mutation can lead to speciation and selection of the fittest organisms. The type of behavior selection results in the preference of the partners based on the mating and reproducing capabilities.
Therefore, option C. the peacock without impressive tails will be less likely to mate and reproduce.
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Draw a table with two columns labelled physical change and chemical change .Write the following changes in the correct column .
water boiling
a car rusting
petrol burning
beer fermenting
ice cream melting
wind blowing
milk turning sour
seawater evaporating
sugar dissolving in tea
food being digested
bleach cleaning a dirty cloth
Answer:
Explanation:
P = Physical Change
C = Chemical Change
water boiling P
a car rusting C
petrol burning C
beer fermenting C
ice cream melting P
wind blowing P
milk turning sour C
seawater evaporating P
sugar dissolving in tea P
food being digested C
bleach cleaning a dirty cloth
arrange the bromine-containing compounds cabr2, br2, asbr3, cbr4 in order of increasing normal boiling point.
Answer:
Br2, CBr4, AsBr3, CaBr2. this is the increasing order of boiling point
The arrangement of given compound in the increasing order of normal boiling point is Br₂ < CBr₄ < AsBr₃ < CaBr₂.
What is normal boiling point?Norma boiling point of any liquid is that point where the vapor pressure is equal to the standard sea level atmospheric pressure.
And boiling point is directly proportional to the strength of bond which is present between the atoms of any compound.
As we know that ionic bond is the strongest bond and in CaBr₂ ionic bond is present so the boiling point of this compound will be highest.In AsBr₃, bromine is more electronegative than arsenic and arsenic also have one lone pair on it so some dipole moment develope in it and then this compound will have boiling point less than CaBr₂.CBr₄ is a covalent compound as in this compound bromine is present which is more electronegative but overall dipole moment of this compound is zero.Br₂ is also a covalent molecule and it has no dipole moment in it and have minimun boiling point among all compounds.So, correct order will be Br₂ < CBr₄ < AsBr₃ < CaBr₂.
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Describe a method you could use to carry out paper chromatography.
paper chromatography, in analytical chemistry, technique for separating dissolved chemical substances by taking advantage of their different rates of migration across sheets of paper..The method consists of applying the test solution or sample as a spot near one corner of a sheet of filter paper.
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I will give thanks, profile thanks, brainliest and 5 star
Answer: E.) C2N2H8
Explanation:
Answer:
E ) C2N2H8
Explanation:
Advantages and disadvantages of titration?
Answer:
What are the advantages of titration?
Titrimetric analysis commonly referred to as volumetric analysis offers distinct advantages over cumbersome gravimetric methods:
Speed of analysis.
Instantaneous completion of reactions.
Greater accuracy due to minimization of material loss involved in decanting, filtration, precipitation or similar operations.
Explanation:
Disadvantages
It is a destructive method often using up relatively large quantities of the substance being analysed.
It requires reactions to occur in a liquid phase, often the chemistry of interest will make this inappropriate.
It can produce significant amounts of chemical waste which has to be disposed of.
It has limited accuracy.
hope this helps Please inform me if its helpful
The advantages of titration:
It is generally cheap, requiring little in the way of equipment.It does not require a high level of skill.It can often be done rapidly.Results are immediately available.Disadvantages
It is a destructive method often using up relatively large quantities of the substance being analysed.It requires reactions to occur in a liquid phase, often the chemistry of interest will make this inappropriate.It can produce significant amounts of chemical waste which has to be disposed of.What is titration?Titration is a quantitative technique where a solution of a known concentration is used to determine the concentration of the unknown solution.
Titration is a technique where a solution of known concentration is used to determine the concentration of an unknown solution.
The Titration Process Is Influenced by the Following Factors:
Measuring methodInstrument (instrument uncertainty/abrasion of the burette)Electrodes (electrode uncertainty/alteration of electrodes)HandlingBalance (weighing error)TemperatureVolumetric solution (change of the concentration, through alteration, carbon dioxide, vaporation of water/solvent)Learn more about titration here:
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A container that can't expand, may explode from the ________ in pressure.
Help me Please
Is boiling an egg a physical or a chemical change? Explain your answer.
Answer:
it's a chemistry change
Explanation:
this is because heat is causing permanent changes and can no longer be changed back to its original atate
pls help :)))))))pop
Answer:
c-a-b
Explanation:
A small container of perfume is opened in a classroom. Soon every student in the room smells the perfume. Explain this in terms of molecules.
Answer: possibly diffusion
Explanation:
all particles are in motion unless at a certain degree so they'd spread throughout the room diluting as they continue to spread out.
The science of measuring chemicals that go into and come out of a reaction is called
O meteorology
O atomic mass measuring
O molar metrology
o stoichiometry
Answer:
I think it is stoichiometry
I need help ASAP my final 20 points!!!
Select the three hypotheses that explain why being born in the United States leads to a higher chance of developing allergies
- The weather patterns in the United States bring more allergens compared to other countries
- cultural practices may play a part because some cultural foods have different anti-allergenic properties
- other factors which might influence why there are more children with allergies in the United States include climate, obesity, and the typical western diet with high amounts of processed foods.
- children in the United States are taught to believe in allergens, but really allergens don’t really exist.
- The hygiene hypothesis claims that children in the United States are not exposed to enough germs in their infancy and childhood to develop their immune system‘s properly.
The three hypotheses that explain why being born in the United States
leads to a higher chance of developing allergies include the following:
The weather patterns in the United States bring more allergens compared to other countries.Other factors which might influence why there are more children with allergies in the United States include climate, obesity, and the typical western diet with high amounts of processed foods.The hygiene hypothesis claims that children in the United States are not exposed to enough germs in their infancy and childhood to develop their immune system‘s properly.Allergies are caused by a host of factors such as :
ClimateDietImmune systemThese factors is the reason why the chosen hypotheses are the most
appropriate.
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Why weren’t scientists initially concerned that the ocean absorbs excess carbon dioxide?
Why scientists weren’t initially concerned that the ocean absorbs excess carbon dioxide was because they saw carbon dioxide as a pollutant
What is a pollutant?Generally, A pollutant is a material found in amounts that are harmful to organisms or exceed an environmental quality standard.
In conclusion, scientists saw carbon dioxide as a major air pollutant, and the water was helping by absorbing it.
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5 grams of sodium bicarbonate, a white powdery solid, is placed in an empty red balloon. 100 grams of acetic acid, a clear aqueous solution, is placed in the plastic bottle. The balloon is carefully attached to the bottle so that no air can get in or out and the powder does not fall into the bottle. Once attached, the apparatus is placed on a balance and the contents are mixed. Bubbles form, the balloon inflated, and the white powder is no longer visible. Which of the these statements would match your observations? A) A chemical reaction has occurred and the mass will increase. B) A chemical reaction has occurred and the mass will decrease. C) A physical reaction has occurred and the mass will decrease. D) A chemical reaction has occurred and the mass will remain the same.
Answer: im pretty sure its D
Explanation:
A solution containing 0.60 moles of sodium hydroxide is added to excess magnesium sulfate in solution. A white solid, magnesium hydroxide, is formed.
a) Write a balanced equation including the states of reactants and products.
b) write the name of the other product formed?
Explanation:
and then name of the other product will be sodium sulphate
La superficie del sol se encuentra una temperatura de 6000 °C mientras que su núcleo tiene aproximadamente 10,000,000°C.
¿En qué parte del sol las partículas tendrán mayor velocidad?
¿Como será la velocidad de estas partículas comparada con las que están en una limonada a 5 °C?
¿que forma energía está relacionada con la velocidad en las partículas?
AYUDAAAA LO NECESITO YA
La energía cinética está relacionada con la velocidad de las partículas.
Sabemos que la velocidad de las moléculas de gas depende de la temperatura del cuerpo. La temperatura de un cuerpo es una medida de la energía cinética promedio de las moléculas del cuerpo.
Debemos notar que cuanto mayor es la temperatura del cuerpo, mayor es la velocidad de sus moléculas. Por lo tanto, a una temperatura de 10,000,000 ° C, las moléculas en el núcleo del sol tienen una velocidad mayor que las moléculas en la superficie del sol.
Todas las moléculas, ya sea en el núcleo o en la superficie del sol, se mueven a mayor velocidad que las moléculas de la limonada a una temperatura mucho más baja. La energía cinética está relacionada con la velocidad de las partículas.
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HELP PLEASE ASAP ILL GIVE BRAINLEST
Answer:
D
Explanation:
braineist pls???????????
Answer:
C
Explanation:
gram is bigger than atom duh
a side reaction occurs when acid is added to the system. which species reacts with the acid?
A side reaction occurs when acid is added to the system, so the species reacts with the acid is base.
What are acids?Acids are those species which have a pH range in between 0 to 7, generally acids are present with hydrogen atom in their molecular formula.
If in any reaction after adding the acid, side reaction wiull occur then in this condition base will reacts with the acid as it has the opposite behavior as of acid and formation of salt & water molecules takes plavce.
Hence the needed species is base.
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The Haber process can be used to produce ammonia (NH3) from hydrogen gas (H2) and nitrogen gas (N2). The balanced equation for this process is shown below. 3H2 N2 Right arrow. 2NH3 The molar mass of NH3 is 17. 03 g/mol. The molar mass of H2 is 2. 0158 g/mol. In a particular reaction, 0. 575 g of NH3 forms. What is the mass, in grams, of H2 that must have reacted, to the correct number of significant figures? 0. 1 0. 102 0. 10209 0. 1021.
Answer:
B
Explanation:
We are given that ammonia can be produced from hydrogen gas and nitrogen gas according to the equation:
[tex]\displaystyle 3\text{H$_2$} + \text{N$_2$} \longrightarrow 2\text{NH$_3$}[/tex]
We want to determine the mass of hydrogen gas that must have reacted if 0.575 g of NH₃ was produced.
To do so, we can convert from grams of NH₃ to moles of NH₃, moles of NH₃ to moles of H₂, and moles of H₂ to grams of H₂.
We are given that the molar masses of NH₃ and H₂ are 17.03 g/mol and 2.0158 g/mol, respectively.
From the equation, we can see that two moles of NH₃ is produced from every three moles of H₂.
With the initial value, perform dimensional analysis:
[tex]\displaystyle \begin{aligned} 0.575\text{ g NH$_3$}& \cdot \frac{1\text{ mol NH$_3$}}{17.03\text{ g NH$_3$}} \cdot\frac{3\text{ mol H$_2$}}{2\text{ mol NH$_3$}} \cdot \frac{2.0158\text{ g H$_2$}}{1\text{ mol H$_2$}} \\ \\ & = 0.102\text{ g H$_2$}\end{aligned}[/tex]
*Assuming 100% efficiency.
Our final answer should have three significant figures. (The first term has three, the second term has four (the one is exact), the third term is exact, and the fourth term has five. Hence, the product should have only three.)
In conclusion, our answer is B.