Answer:
Substances can change phase—often because of a temperature change. At low temperatures, most substances are solid; as the temperature increases, they become liquid; at higher temperatures still, they become gaseous.
The process of a solid becoming a liquid is called melting. (an older term that you may see sometimes is fusion). The opposite process, a liquid becoming a solid, is called solidification. For any pure substance, the temperature at which melting occurs—known as the melting point—is a characteristic of that substance. It requires energy for a solid to melt into a liquid. Every pure substance has a certain amount of energy it needs to change from a solid to a liquid. This amount is called the enthalpy of fusion (or heat of fusion) of the substance, represented as ΔHfus. Some ΔHfus values are listed in Table 10.2 “Enthalpies of Fusion for Various Substances”; it is assumed that these values are for the melting point of the substance. Note that the unit of ΔHfus is kilojoules per mole, so we need to know the quantity of material to know how much energy is involved. The ΔHfus is always tabulated as a positive number. However, it can be used for both the melting and the solidification processes as long as you keep in mind that melting is always endothermic (so ΔH will be positive), while solidification is always exothermic (so ΔH will be negative).
A 100 watt solar power panel usually costs $146 they are on sale for 0.75 of the regular price what is the sale price
a bond in which only one pair of
electrons is shared?
Answer:
A single covalent bond
Explanation:
A single covalent bond is when only one pair of electrons is shared between atoms. A sigma bond is the strongest type of covalent bond, in which the atomic orbitals directly overlap between the nuclei of two atoms.
Answer:
Single covalent bond.
Explanation:
Single covalent bond is the type of bond in which only one pair of electrons is shared between atoms.
[tex]\rule[225]{225}{2}[/tex]
Hope this helped!
~AH1807Two protons and two neutrons are released as a result of this reaction. Superscript 222 subscript 86. Rn Right arrow superscript 218 subscript 84. Po ? Which particle is released? one alpha particle two beta particles one alpha and one beta particle one high-energy photon.
The particle released in the reaction has been an alpha particle. Thus, option A is correct.
The release of protons and neutrons in a reaction has been nuclear reactions. The reactions results in the change in the atomic mass of the atom, with the formation of new atom. The extra mass has been released in the form of energy.
The release from the given reaction has been:
[tex]\rm ^{222}_{66}Rn\;\rightarrow\;^{218}_{84}Po\;+\;^A_ZX[/tex]
Where, X has been the particles that has been released with the nuclear reaction. The superscript A has been the Mass of particle, and subscript Z has been the atomic number.
According to the law of conservation, the mass has been constant on both the product and the reactant side. Thus, the mass and atomic number of eliminated particles has been given as:
[tex]\rm 222=218+A\\A=222-218\\A=4[/tex]
The atomic mass of the particle has been 4.
[tex]\rm 86=84+Z\\Z=86-84\\Z=2[/tex]
The atomic number of the particle has been 2.
The element with atomic mass 4, and atomic number 2 has been the Helium particles, [tex]\rm ^4_2He[/tex]. It has been an alpha particle. Thus, the particle released in the reaction has been an alpha particle. Thus, option A is correct.
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Answer:
A
Explanation:
magine that you are a water molecule in a group of many water molecules. Write a letter to a friend telling them about your journey through the water cycle on Earth. You can begin your journey anywhere you’d like, but you must complete an entire cycle and end the journey where you began. Write your letter in complete sentences. Use each of the following terms correctly in your letter: • condensation • evaporation • precipitation • collection (HELP PLS ILL GIVE 54 points *all my points* AND GIVE BRAINLIEST HELP PLS)
Answer:
Explanation:
One day I was sitting on a leaf, in the early morning if a Tuesday, and I was just relaxing there. I then heard Bob( the water molecule next to me) say that he heard it was going to get pretty hot today. As the day went on I started to get pretty warm and I starting to evaporate and fly into the sky! It was really weird to see the world from up high. I stayed up there bouncing between clouds with Bob for a few hours, until the wind started to pick up and it got colder. I then started to shiver and began condensing with the other water molecules (and Bob). As it got colder we began to plummet to the earth really fast in the precipitate form of a water droplet. We hit the ground with a big ker-plop! I looked around me and we weren't the only ones. A bunch of other droplets had started to collect and form a puddle.
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Can someone help me please
Answer: The correct pairs of elements likely to form ionic compounds are, potassium and sulfur, magnesium and chlorine. The answer is argon please give me brainlist
Explanation:
What’s clues indicate that a chemical reaction has occurred?
Answer:
Color change, formation of bubbles, and temperature change
Fluorine-18 undergoes positron emission as shown:
18 F + 4x +48
Enter the appropriate values for A and Z and the chemical
symbol for X
A:
Z:
83
1
X:
Answer:Answer:
40-18 fl =>40-cl+cl+0-1e sorry if im rong
Explanation:
When [tex]^1^8F[/tex] undergoes positron emission, the product nucleus is, [tex]^1^8O[/tex].
What is a positron emission?In positron emission, also called positive beta decay (β+ decay), a proton in the parent nucleus decays into a neutron that remains in the daughter nucleus, and the nucleus emits a neutrino and a positron, which is a positive particle like an ordinary electron in mass but of opposite charge.
When a proton is converted into a neutron then the positron emission takes place as follows.
[tex]^1_1p\;\rightarrow\;^1_0n\;+\;^0_+1e[/tex]
A positron is represented by the symbol. Therefore, when a positron emission occurs then the resultant nuclei atomic number decreases by a unit mass.
The general equation representing positron emission is as follows.
[tex]^M_ZA\;\rightarrow\;^M_Z_-_1 B\;+\;^0_+1e[/tex]
Hence, fluorine-18 decays by positron emission as follows.
[tex]^1^8_9F\;\rightarrow\;^1^8_8n\;+\;^0_+1e[/tex]
Therefore, when [tex]^1^8F[/tex] undergoes positron emission, the product nucleus is, [tex]^1^8O[/tex].
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Can someone help please
Answer:
To achieve stability
Explanation:
Chemical reactions happen so that the atoms of the elements involved in the chemical reaction will become stable and therefore achieve stability.
WILL GIVE BRAINLIEST
Which model provides more information-a chemical formula or a sketch of the molecule
like in the structural formula? Explain your reasoning.
Answer:
Explanation
:Both b/c a chemical formula tells you how many and a sketch formula shows how they are bonded together.
Molecular formulas show how many atoms of each element one molecule of a compound contains. Note: Ionic compounds are generally crystalline solids with high melting points. Other compounds, however, have very different properties.
RNA is a double strand. True or False?
Answer:
False, RNA is single stranded, DNA is double stranded and forms a double helix
Explanation:
1.37x1020 uranium atoms
Explanation:
1397.4 uranium atoms......
In the TCA cycle, ____ oxidation(s) use(s) NAD as the oxidizing agent while ____ oxidation(s) use(s) FAD as the oxidizing agent.
Tricarboxylic acid cycle often occur in stages. In the TCA cycle, 3 oxidation(s) use(s) NAD as the oxidizing agent while 1 oxidation(s) use(s) FAD as the oxidizing agent.
Tricarboxylic acid cycle commonly called TCA cycle is also regarded as the Krebs cycle and citric acid cycle. It is known to be the second stage of cellular respiration.It consist of a three-stage process where living cells uses organic fuel molecules in the presence of oxygen to take-up energy that is needed for growth and division.
See full question below
In the TCA cycle, ____ oxidation(s) use(s) NAD + as the oxidizing agent while ____ oxidation(s) use(s) FAD as the oxidizing agent.
a. 0; 4
b. 1; 3
c. 2; 2
d. 3; 1
e. 4; 0
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what are some negative impacts on the environment and society when the water cycle is disrupted and drought occurs ?
Some of the negative impact of disruption in water cycle are adverse environment, with affected farming, hydroelectricity, and deforestation.
The water cycle has been operated in the environment for the conversion of water in the different states. The water cycle has been operated with the conversion of water from the water body to the clouds by evaporation.
The evaporated water has resulted in clouds, that have been condensed and precipitated in the form of rain. The water cycle helps in maintaining the water balance in the ecosystem. It made the water available for use as well.
The drought has been the condition of the scarcity of water. In this condition, there has been a disruption of the water cycle. Some of the negative impacts resulting from the disruption of the water cycle are:
Adverse environmental conditionsFarming affected by water scarcityUnavailability of hydroelectricityDeforestationFor more information about water cycle, refer to the link:
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2) Nitrogen gas will react with hydrogen gas to produce ammonia, NH3, How many
moles of hydrogen gas are required to produce 0,86 moles of NH3?
Answer:
12 grams of hydrogen gas
and 56 grams of nitrogen gas
The molar mass of ammonia is 17 g/mol.
68 grams of ammonia corresponds to
17g/mol
68g
=4moles
4 moles of ammonia will be obtained from
2
4×1
=2 moles of nitrogen and
2
4×3
=6 moles of hydrogen.
The molar masses of nitrogen and hydrogen are 28 g/mol and 2 g/mol respectively.
2 moles of nitrogen corresponds to 2×28=56 grams.
6 moles of hydrogen corresponds to 6×2=12 grams.
Which of the following methods of heat transfer causes the tectonic plates to move?
Conduction
Convection
Evaporation
Radiation
I NEED MORE HELP ASAPP
Answer:
1) Gas
2) Higher
3) Increases
4) Higher
Explanation:
How do characteristic properties help you determine whether a chemical
change or a physical change has occurred? I
Answer: The difference between a physical reaction and a chemical reaction is composition. In a chemical reaction, there is a change in the composition of the substances in question; in a physical change there is a difference in the appearance, smell, or simple display of a sample of matter without a change in composition.
Explanation:
What type of volcano is formed at a weak spot in the middle of a plate?
a.
lava
c.
hot spot
b.
fault
d.
plate
Hot spot volcano is the type of volcano which is formed at a weak spot in
the middle of a plate.
Hot spot volcano is an area in the Earth crust which is characterized by large
amount of heat flow in the area due to the volcanic activity. Hot spot
volcano is formed at the middle of the plate as against junctures in which
other types are formed.
The weak spot is what gives rise to the unusual heat flow which makes hot
spot volcano most appropriate.
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A force is a push or a pull under the right circumstances anything can exert a force push a notebook or some other object so that it slides across a table or desktop what force causes the notebook to start moving what force causes the notebook to stop moving?
Answer:
the force that you applied caused the notebook to move.the force applied on the notebook by the table causes it to stop moving. this is because after sometime the book uses up the force and later the force you applied is less than that of the force by the table.
1 point
A system that absorbs energy from its surroundings is said to be: *
Answer: Exothermic.
Explanation:
Exo means “outside” and the outside relates to surroundings so it’s my best choice.
Answer:
endothermic is the answer
For the following hypothetical reaction:
3A + 12B --> 3C
How many moles of B will you need to convert 5 moles of A into as many moles of C as possible?
Answer:
20
Explanation:
You need 4 times the amount of B, compared to a (there is a 3A:12B which reduces to 1:4), so 4 times 5 is 20.
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Which of the following statements describes sound energy?
Sound energy does not travel at all.
Sound energy needs a medium to travel through.
Sound energy can travel in empty space.
Sound energy can only travel through air.
Answer:
C.
Explanation:
Help. 50 points. Need honest answers.
Answer:
ok
Explanation:
How many moles are in 9.12 x 1023 molecules of sugar?
Answer:
1.514 moles
Explanation:
For this problem you want to use dimensional analysis and cancel out your molecules of sugar and be left with moles of sugar. We know that 1 mole (of anything) = 6.022 x 10 ^ 23 molecules, so we should use that conversion to help us. Start with 9.12 x 10 ^23 molecules and divide by 6.022 x 10 ^ 23 molecules, and you will be left with moles.
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can you help me with this
Answer:
I think it is A
Explanation:
if I am wrong I am so so so sorry
but i'm pretty sure I am right.
please let me know if I am right :)
Figure 1
Describe how a frog grows. Why do you think the eggs are found in the water? Where do you think fertilization happens?
The process of fertilization occurs externally in frogs.
Stages of lifecycleA full growth of frog occurs when it passes through five stages of its life cycle. During a frog's metamorphosis, an egg will hatch and a tadpole appear in which the back legs emerge first, then front legs, and finally it become a full grown adult frog.
Eggs of frogA frog's eggs are found in water because they do not have a hard protective shell like birds and reptiles. The frog's eggs are covered with a glycoprotein, which helps to keep the eggs moist so that's why the frog lays its eggs in water in order to prevent them from drying.
FertilizationIn most species of frogs, fertilization occurs externally. The male frog grabs the female's back and fertilizes the eggs as the female frog releases the eggs. Those eggs which receives the sperm will fertilized so we can conclude that the process of fertilization occurs externally in frogs.
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What is photosynthesis?
Explanation:
the process by which green plants and some other organisms use sunlight to synthesize foods from carbon dioxide and water. Photosynthesis in plants generally involves the green pigment chlorophyll and generates oxygen as a byproduct.
Answer:
photosynthesis is the process of making food by green plants by using sunlight,carbon dioxide, water.
what is waves is energy passing through the medium of water? true or false
i have no idea what you said but for the sake of god its true
which of the following is a characteristic of the modern periodic table
Why can't percent yield be greater than one hundred percent?
Answer:
Percent yield is the maximum amount of product that can be formed in a reaction. Matter cannot be created or destroyed according to the law of conservation of mass, so you cant have over 100%.
Explanation: