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).
the ability to conduct electricity is a characteristic of metallic bonding. this characteristic is best explained by the presence of ________________.
All atoms of an element are______.
Points: 87
Answer:
Alike
Explanation:
How many total atoms does 3Na2S2O3 have
Answer:
21
Explanation:
Let us count the number of individual atoms for Na2S2O3 (the compound name):
Na: 2
S: 2
O: 3
This brings us to a total of 7 atoms for one molecule of sodium thiosulfate. For three of these compounds, we get 3*7=21
how do you find a mole (i need an example) i hate chem pls help
Answer:
I'm pretty sure its just the mass of the sample divided by the molar mass
for example if I had like 7g of carbon and wanted to find the moles, I would divide the mass I have (7g) by the molar mass (the atomic mass value on your periodic table, in this case for carbon it would be 14g)
moles = [tex]\frac{mass}{molarmass} = \frac{7}{14} = 0.5\ moles[/tex]
Hope this helped
How many atoms are in 80.45g of magnesium
Answer:
see below
Explanation:
1. 1 mol Mg = 24.31 g = 6.02 *10^23 atoms
calculate the number of atomsin 80.45g Mg
Numberof atoms = 6.02*10^23 Mg atoms / 24.31 g * 80.45 g
= 1.99*10^24 atoms
2.1 mol C-12 = 12.01g = 6.02 * 10^23 atoms
calculate the mass using
= 12.01 g C / 6.02*10^23 atoms * 100 atoms
= 1.99 * 10^-21 g
Answer:
1.9926 * 10 ^24
Explanation:
Molar Mass - Use Periodic table!
M ( Mg ) = 24.31 g / mole
n = 80.45 g : 24.31 g/mole = 3.31 moles
N a ( Avogadro`s constant ) = 6.02 * 10 ^23
N = Na * n = 6.02 * 10 ^24 * 3.31 = 19.926 * 10 ^23
The material used as a biological sensor is one dimension of 20 mm, the other Are in nanometers
Answer: 20 , 40
I want know the answer now !
which is the best reason given to explain why metals make good electrical conductors?
Answer: Metals are an excellent conductor of electricity and heat because the atoms in the metals form a matrix through which outer electrons can move freely.
Explanation:
How many molecules are in 1.3 moles of water?
Answer:
7.8286e+23
Explanation:
Use Avogadro's number
Please Help
Predict the nature of the indicated covalent
bond. Polar or Non polar
Answer:
Nonpolar
Explanation:
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A tank of syngas produced by coal gasification contains 60.0% carbon monoxide, 30.0% hydrogen, and 10.0% carbon dioxide. What is the mass of hydrogen (in g) in 1.00 cubic meter of this syngas mixture at 1.00 atm and 25.0 °C? (1 m³ = 1000 L)
Considering the ideal gas law, the mass of hydrogen is 24.552 grams.
An ideal gas is a theoretical gas that is considered to be composed of randomly moving point particles that do not interact with each other. Gases in general are ideal when they are at high temperatures and low pressures.
An ideal gas is characterized by three state variables: absolute pressure (P), volume (V), and absolute temperature (T). The relationship between them constitutes the ideal gas law, an equation that relates the three variables if the amount of substance, number of moles n, remains constant and where R is the molar constant of the gases:
P× V = n× R× T
In this case, you know:
P= 1 atmV= 1 m³= 1000 Ln= ?R= 0.082[tex]\frac{atmL}{molK}[/tex]T= 25 °C= 298 °KReplacing in the ideal gas law:
1 atm× 1000 L = n× 0.082[tex]\frac{atmL}{molK}[/tex]× 298 K
Solving:
[tex]n=\frac{1 atmx1000 L}{0.082 \frac{atmL}{molK}x298 K}[/tex]
n= 40.92 mol
The mol of syngas mixture is 40.92 mol.
Syngas mixture contains 30.0% hydrogen. So, there is a mol fraction of [tex]x_{hydrogen} =[/tex]0.3 . Thus, the mols of hydrogen in syngas mixture is calculated as:
40.92 moles of syngas mixture× 0.3= 12.276 moles of hydrogen
Finally, being the molar mass of hydrogen H₂ 2 [tex]\frac{g}{mole}[/tex], then the mass is:
[tex]12.276 molesx\frac{2 grams}{1 mole}[/tex]= 24.552 grams
In summary, the mass of hydrogen is 24.552 grams.
Learn more about ideal gas law:
https://brainly.com/question/4147359?referrer=searchResultsWhat eats a FawnsFoot Mussel?
Answer:
I have no Idea please give more context to your question.
Explanation:
Research the future of energy production. What improvements to (or new methods of) electrical energy production are scientists currently developing? How will they improve on present methods of energy production (what makes these new methods better than the old)? What are the cons of these improvements?
Answer:
Fossil fuels like coal, oil and natural gas supply 80 percent of the world’s energy to warm homes, charge devices and power transportation. They are also the primary human source of greenhouse gas emissions. Stanford scientists broadly agree that curtailing our use of fossil fuels would have significant benefits like improving health and reducing the number and severity of natural disasters, but it’s not yet clear what can replace them.
Explanation:
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
what is the magnitude of the acceleration that is produced when the brakes of a 2.4 x 10
cubed kg car apply a 3.2 x 10 cubed N force to stop the car
Answer:
b 1.3 m/s
Explanation:
newton's second law of motion
What is the wavelength of the above wave?
Answer:
well what above wave?? do you have a picture
Explanation:
the boiling point of water at standard pressure is
Answer:
100 Celsius mostly because water boils at sea level
Which statement is correct about charges?
A.Opposite charges repel
B.Similar charges attract
C.Electrons are positively charged
D.Similar charges repel
Answer:
A.Opposite charges repel[tex] \: \: \: \: [/tex]
D.Similar charges repelcorrect me if I'm wrong
hope it helpsIs sweat a chemical? I am curious to know! NO LINKS OR TROLLS
Answer:
no
Explanation:
stop troll hate
Which description of salt is a physical property?
No combustion
Makes ionic bonds
Product of mixing acids and bases
Solid does not conduct electricity
Answer:
Solid and does not conduct electricity
Explanation:
the valence electrons of metals jump easily to a higher energy orbital when light shines on them then they all fall emiting the excess energy as light which property of metals is explained by this?
Answer:
Lustrous
Explanation:
Metals are lustrous which gives them a property of having Shiny surfaces
The valence electrons of metals jump easily to a higher energy orbital when light shines on them then they all fall emitting the excess energy as light show lustrous property of metals.
What are valence electrons?Valence electrons are defined as a negatively charged particle that can be shared or transmitted between atoms that is found in the outermost shell of an atom. Valence electrons have a crucial role in determining how an atom will behave. The electrical configurations of elements can be used to find valence electrons. The total number of valence electrons in that element is then determined by counting the number of electrons in the outermost shell.
When newly treated, polished, or broken, a material takes on a bright look and conducts electricity and heat reasonably well. Metals are typically ductile and malleable. These traits are the result of the metallic bond that connects the atoms or molecules of the metal.
Thus, the valence electrons of metals jump easily to a higher energy orbital when light shines on them then they all fall emitting the excess energy as light show lustrous property of metals.
To learn more about valence electrons, refer to the link below:
https://brainly.com/question/13993867
#SPJ2
c) A substance has a high melting point and conducts electricity. What type of structure does it have
Answer:
Metallic structure
Explanation:
They have a high melting point due to the strong forces of attraction between the positive ions (cations) and the delocalised electrons. Moreover, they conduct electricity due to the sea of delocalised electrons.
[Extra: It could be an ionic compound since they also have a high melting point, however they only conduct electricity in liquid or aqeouus state.]
which of the following atom could reside in the same group? Explain your answer
What is an example of thermal energy
A) batteries moving a toy
B) riding a bicycle
C) plugging in a tv
D) using an oven to cook
the tree is 18 meters long is an example of
This question is describing a thoroughly opened statement about the length of a three as 18 meters, which in the context of science can be referred to:
- A hypothesis or a result in the scientific method, if one is measuring the length of given objects.
- A measurement, if one is measuring the length of a three or any other object.
In both cases, we can note that the measurement has the following basic structure:
1. A number, defining how large or small the measurement is.
2. A unit, defining the system in which the measurement is reported to the scientific community.
Learn more:
https://brainly.com/question/13501946https://brainly.com/question/733946If the pressure, volume, and temperature of a gas are known, which can most likely be found by using the ideal gas law?
the molar amount of the gas
the partial pressure of the gas
the standard temperature and pressure
the molar mass
Answer:
the molar amount of the gas.
Explanation:
Why does a light bulb turn in When you flip the switch to on?
Explanation:
Flipping a light switch to turn on a light means that the circuit with the light is being closed. When the switch is flipped the opposite way, to turn the light off, the circuit is being opened.
Answer:
You now have an open circuit
Explanation:
The circuit is closed when the switch is flipped the other way to turn off the light.
give me a answer!!!!!!!!!!!!!!!
Answer: i did the ones i knew
1. thorns
2. smell
6. long roots
8. smell
9. thorns
Explanation:
Prokaryotic and Eukaryotic Cells Booklet
Answer:
Power Plant = Mitochondria (Mitochondria is the powerhouse of the cell)
City Limits = Cell Membrane (Outer layer of a cell)
City Hall = Nucleus (The nucleus is the control center in a cell)
City Food Processing Plant (Chloroplast process the cells food)
City Plans = Chromosomes (They contain the genetic information about the cell)
Community = Cytoplasm (Mainly process of elimination)
Explanation:
Explanations are in parenthesis
What type of weathering involves changes in the size or shape of the rock?
A: hydrolysis
B: physical weathering
C: pressure weathering
D: chemical weathering
Answer:
B
Explanation:
The rock is physically weathered down and decreases in size.