Answer:
Try everything
O 5.94 moles
0 10.0 moles
0 022 x 10^23 moles
0 3.00 moles
Explanation:
The enthalpy of fusion for Al is 10.7 kJ/mol. What is the energy change when 30.8 g of Al solidifies at 660°C?
The enthalpy of fusion for Al is 10.7 kJ/mol. -12.2 kJ is the energy change when 30.8 g of Al solidifies at 660°C.
What is Enthalpy of Fusion ?The amount of energy needed to change 1 mole of substance under state change at constant temperature and pressure is called enthalpy of fusion. It is also known as Latent heat of fusion. Unit of enthalpy of fusion is kJ/mol.
How to find the change in energy ?To find the change in energy use this expression:
q = n ΔH
where
q = Energy change
n = number of moles
ΔH = Molar enthalpy
Number of moles (n) = [tex]\frac{\text{Given mass}}{\text{Molar mass}}[/tex]
= [tex]\frac{30.8\ g}{26.98\ \text{g/mol}}[/tex]
= 1.141 mol
Now put the values in above formula we get
q = - n ΔH [Negative sign is used because Al solidifies here]
= - (1.141 mol × 10.7 kJ/mol)
= -12.2 kJ
Thus from the above conclusion we can say that The enthalpy of fusion for Al is 10.7 kJ/mol. -12.2 kJ is the energy change when 30.8 g of Al solidifies at 660°C.
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PLEASE ANSWER QUICK... WILL GIVE BRAINLIEST
The relative humidity is 100%, and the temperature is hot. In a few sentences, explain how the weather would change if the temperature drops and becomes cool.
Answer:
Humdity would decrease hence temprature would do the same, hence tundra are called deserts at times.
Explanation:
If you keep on decreasing the temperature without changing the air's moisture content significantly, eventually you'll reach 100 percent relative humidity, and then water vapor will start to condense to form dew.
What happens when humidity is at 100% and the temperature drops?Dew Point. When the relative humidity reaches 100 percent, dew forms. Dew point refers to the temperature at which air reaches saturation by water molecules. Warmer air can hold more water molecules, and as that warm air cools, it loses water vapor in the form of condensation.
What happens when it reaches 100% relative humidity?When relative humidity reaches 100 percent or is saturated, moisture will condense, meaning the water vapor changes to liquid-vapor. Thus, the saturation level of air is related to the air's temperature.
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The yellow light given off by a sodium vapor lamp has a wavelength of 589nm. What is the frequency of this radiation? Please show all work.
Answer:
5.09 x 10⁶ s⁻¹ = 5.09 x 10⁶ Hz
Explanation:
The relation between frequency (ν) and wavelength (λ) is given by:
λ = c/ν
where c is the speed of light (2.998 m/s) and it is a constant.
So, we first convert the wavelength from nanometers (nm) to meters (m) (1 nm = 1 x 10⁻⁹):
λ= 589 nm x (10⁻⁹ nm/1 m) = 5.89 x 10⁻⁷ m
Then, we calculate the frequency from the equation:
λ = c/ν ⇒ ν = c/λ = (2.998 m/s)/(5.89 x 10⁻⁷ m) = 5.09 x 10⁶s⁻¹ = 5.09 x 10⁶ Hz
(iii) Observe the following diagram and answer the following questions :
X Х
Y
(A) Identify elements X and Y.
(B) Do these elements belong to the same group?
(C) Which element is more electropositive in nature? Why?
how many bananas are equal to 7.50 moles of bananas?
Answer:
4.52×10^24
Explanation:
N = n × Na
where; N = no. of bananas
n = no. of moles
Na = Avogadro's constant
Which is 6.02×10^23
N = 7.5 × 6.02×10^23
N =4.515×10^24
A text book is on a desk. If the book weighs 14 N and the area of the book is 0.60 m 2 , what pressure is the book exerting on the desk?
Answer:
Explanation:
Pressure = Force / Area
F = 14 N
Area = 0.60 m^2
Pressure = 14/0.60
Pressure = 23.3 N
If you are worried about significant digits, the answer is 23
chemical change grade 10 mind map
Chemical change: A chemical reaction is the change of one chemical substance into another chemical substance. For instance: The rusting of iron, the curdling of milk, the digestion of food, breathing, etc.
What is a chemical reaction?
A chemical reaction results in a chemical change because a new material has entirely different properties from the original substance. In a chemical reaction, atoms rearrange themselves.Reactants are the chemicals that participate in a chemical reaction.Products are the new compounds created as a result of a chemical process. An illustration of a chemical reaction is burning magnesium in the air to produce magnesium oxide.2Mg(s) + O2(g) △→ 2MgO(s)The magnesium ribbon is cleaned with sandpaper before being burned in the air. This cleans the magnesium ribbon's surface of the basic magnesium carbonate protecting coating.Reactant: Materials that participate in a chemical reaction are referred to as reactants. Mg and O2, as an example.A product is a newly created substance that results from a chemical reaction. Example: MgO.A chemical reaction is the change of one chemical substance into another chemical substance.
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Chemical change is the change chemical substance is transformed into another chemical substance.It is irreversible in nature , for example Reaction of medicine in body , milk to curd etc.
What is the difference between chemical and Physical change?1)Physical change temporary or reversible in nature but chemical change is irreversible in nature
2)In physical change there no new product is formed but in chemical change there formation of new product takes .
3) Physical change is change sin shape ,size or state for example freezing of water , melting of wax , and example of Chemical change are Burning of coal, digestion of food
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Thermal expansion occurs when particles of matter move farther apart as temperature increase. True or false ?
Answer:
true
Explanation:
Describe the energy of the products in comparison to the energy the atoms had when the were wandering around the room free.
Answer: The atoms of the solid products are tightly packed whereas those in gas are loose.
Explanation:
Atoms in the solid structure are linked to each other by strong force of attraction and they collectively form an three-dimensional structure. The binding of the atoms form the shape of the solid product. The gas exhibit free atoms in it. The atoms are not linked to one another by strong force of attraction. The atoms as a part of gas have higher energy as those present in the solid products. So, the atoms of the gas wander freely as compared to those in the solid products.
What is the reason why the fermentation products acetate and hydrogen gas (H2) are never abundant in aerobic soils and sediments
Acetate and hydrogen gas (H2) is never abundant in aerobic soils and sediments because they are tiny, highly reduced molecules that many bacteria that breathe oxygen and nitrates quickly absorb to use as fuel for energy generation.
Why are acetate and hydrogen gas not abundant in aerobic soils and sediments?Hydrogen is a substrate for methanogenic archaea and, along with acetate, one of the most significant intermediates in the methanogenic breakdown of organic materials. Numerous methanogenic environments exhibit contributions of H₂ to CH₄ production that are both significantly lower and significantly higher than is considered usual. H₂ is rapidly converted in methanogenic settings due to the simultaneous generation by fermenting and syntrophic bacteria and consumption by methanogenic archaea.
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changing the number of _______ makes an atom stable or unstable and creates different isotopes of the same element with a different ______ (pick two that best fits.)
a.) atomic mass
b.) atomic number
c.) protons
d.)neutrons
e.)electrons
f.) ion
g.)neutral
The neutrons are the neutral sub-atomic particles present in the nucleus. The variation in the number of neutrons produces isotopes that have different atomic mass. Thus, options 1. d and 2. a are correct.
What is an isotope?An isotope is said to be an atom of an element that have a different atomic mass but the same atomic number due to the variation in the neutrons in the nucleus. The neutrons have a neutral charge that makes the atom stable.
When a neutron is added or lost it makes the nucleus of the atom unstable leading to radioactive decay. The isotopes have the same constant number of protons in their nucleus.
The atomic number of the atom remains the same due to the stable proton number but varies the atomic mass due to the change in the number of neutrons.
Therefore, options d and a. neutrons and atomic mass are the correct blanks.
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Carbon dioxide and water are produced when ethanol, C2H5OH, is burned in oxygen. The number of moles of CO2 that is produced when burning 6.0 mol of ethanol is
The number of moles of CO₂ that is produced when burning 6.0 mol of ethanol is 12 mol.
What is Balanced Chemical Equation ?The balanced chemical equation is the equation in which the number of atoms on the reactant side is equal to the number of atoms on the product side in an equation.
Now we have to write the balanced equation
C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O
We can see that every 1 mole of ethanol we will get 2 mole of CO₂.
So 6.0 mol of ethanol we will get = 6.0 × 2.0
= 12 mol of CO₂
Thus from the above conclusion we can say that The number of moles of CO₂ that is produced when burning 6.0 mol of ethanol is 12 mol.
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SCIENCE
Does combustion need oxygen?
A. Yes
B. No
Answer: a. Yes
Explanation:
Answer:
A. yes
Explanation:
In order to burn this fuel, oxygen is needed, as it is with any fire. The waste products from the combustion process are water and carbon dioxide. Thus, we breathe because oxygen is needed to burn the fuel (sugars and fatty acids) in our cells to produce energy The air we breathe contains about 21% oxygen.
what is the name of this branched alkane?
Answer:
Explanation:
3-methyl pentane.
Answer:
the answer is methyl pentane
Which of the following is NOT a property of metals?
A - shiny
B - ductile
C - can be solids, liquids, or gases
D - malleable
Answer:
C - can be solids, liquids, or gases
Explanation:
Which federal agency makes sure federal wildlife laws are followed?
US Forest Service
US Fish and Wildlife Service
Bureau of Land Management
National Park Service
Answer:
us fish and wildlife service
Explanation:
the 2nd choice
Answer:
US Fish and Wildlife Service
Al +CI = Al CI3
how do i solve this
Think about a synthetic material that you use every day. How
could that material be improved to better fit its function?
explanation: Synthetic fiber or synthetic fibre (in British English; see spelling differences) are fibers made by humans through chemical synthesis, as opposed to natural fibers that are directly derived from living organisms. They are the result of extensive research by scientists to improve upon naturally occurring animal and plant fibers. In general, synthetic fibers are created by extruding fiber-forming materials through spinnerets, forming a fiber. These are called synthetic or artificial fibers. Synthetic fibers are created by a process known as polymerization, which involves combining monomers to make a long chain or polymer. The word polymer comes from a Greek prefix "poly" which means "many" and suffix "mer" which means "single units". (Note: each single unit of a polymer is called a monomer). There are two types of polymerization: linear polymerization and cross-linked polymerization.
Plzzzzz I need help ASAP
Answer:
i) B, ii) A, iii) C
Explanation:
give me brainliest
how many molecules are there in 1.5 mol of methane
Answer: A mole of something means that there are 6.02 X 10^23 of that something. So, a mole of methane molecules is 6.02 X 10^23 methane molecules. So, 1.5 moles of methane will contain 1.5*(6.02 X 10^23) = 9.0 X 10^23 methane molecules
Explanation:
difference between solute and solvent
When one substance dissolves into another, a solution is formed. A solution is a homogeneous mixture consisting of a solute dissolved into a solvent . The solute is the substance that is being dissolved, while the solvent is the dissolving medium. Solutions can be formed with many different types and forms of solutes and solvents.
Explanation:
solute are substance that dissolve in solvent
solvent are substance that dissolve solute
Guys pleaseeeee help:
- Which element is a member of the alkaline earth metals and has 12 neutrons?
- A burnt piece of toast is covered in this element. It is the fourth most abundant element and makes up many living things.
- Which element is an inert gas found in group VIII that produces a red glow in lights?
Answer:
Carbon- A burnt piece of toast is covered in this element. It is the fourth most abundant element and makes up many living things.
Magnesium- Which element is a member of the alkaline earth metals and has 12 neutrons?
Neon- Which element is an inert gas found in group VIII that produces a red glow in lights?
Suppose a aqueous solution of phosphoric acid () is prepared. Calculate the equilibrium molarity of . You'll find information on the properties of phosphoric acid in the ALEKS Data resource.
The equilibrium molarity HPO²₄- = 6.2 x 10⁻⁸M See the explanation below.
What is Equilibrium Molarity?The molar concentration of a certain species in a solution is known as equilibrium molarity.
What is the calculation showing the above answer?
The initial concentration H₃PO₄ = 0.31 M
Kₐ₁ = 6.92 x 10⁻³ (See Image 1 attached)
Kₐ₁ = [H⁺][tex]_{eq}[/tex][H₂PO₄-][tex]_{eq}[/tex] / [H₃PO₄][tex]_{eq}[/tex]
6.92⁻³ x 10 = [(x) * (x)] / (0.31 M - x)
Solving for x, x = 0.043 M
[H+] = x = 0.043 M
[H₂PO₄-] = x = 0.043 M 0.0429805
Kₐ₂ = 6.2 x 10⁻⁸
See the second attached table
Kₐ₂ = [H+][tex]_{eq}[/tex] [HPO₄²-]eq / [H₂PO₄-]eq
6.2 x 10⁻⁸ = [(0.043 M + x) * (x)] / (0.043 M - x)
Solving for x, x = 6.2 x 10⁻⁸ M
[H₂PO₄-]eq = x = 6.2 x 10⁻⁸ M
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please help me out i will give you brainlist. 0.500 is wrong
============================================
Work Shown:
Using the periodic table, we see that
1 mole of carbon = 12 grams1 mole of oxygen = 16 gramsThese are approximations and these values are often found underneath the atomic symbol. For example, the atomic weight listed under carbon is roughly 12.011 grams. I'm rounding to 2 sig figs in those numbers listed above.
So 1 mole of CO2 is approximately 12+2*16 = 44 grams. The 2 is there since we have 2 oxygens attached to the carbon atom.
-------------------
Since 1 mole of CO2 is 44 grams, we can use that to convert from grams to moles.
11.0 grams of CO2 = (11.0 grams)*(1 mol/44 g) = (11.0/44) mol = 0.250 mol of CO2
In short,
11.0 grams of CO2 = 0.250 mol of CO2
This is approximate.
We don't need to use any of the information in the table.
Answer:
.250
Explanation:
Write the formula and determine the percent by mass of the salt in barium hydroxide octahydrate *
(show work)
Answer:
315.51g/mol
Explanation:
137(33 + (16.00 + 1.01) 2 + 8 [1.01 (2) + 16.00] = 315.51g/mol
an example of xenon (Xe)
Answer: i am not sure what you mean but here are some product of xenon stroboscopic lamps, photographic flash lamps, high-intensive arc-lamps for motion picture projection, some lamps used for deep-sea observation, bactericidal lamps, sunbed lamps and high-pressure arc all use this gas. In fact, you probably see xenon lamps on a regular basis and if you want compounds : Xe2F2, XeF4, XeO3, XeF6....
Explanation:
Which statements describe band theory? Check all that apply.
Electrons all have approximately the same energy.
Electrons move among orbitals of different energies.
Electrons move freely among atoms (delocalized).
Answer:
b c
Explanation:
right
Answer:
it was A C for me
Explanation:
No attempt was made to test sodium with hydrochloric
acid. Why not?
Answer:
the reaction is violent and quick
Explanation:
explain why dilute trioxosulphate vi acid is not used to prepare carbon 4 oxide from calcium
trioxocarbonate 4
Answer:
H2SO4 cannot be used with CaCO3 to produce CO2 gas
Explanation:
Because it does not dissolve in water- it forms a barrier on the surface of the unreacted CaCO3 which prevents any further reaction. A small volume CO2 is produced, this stops in short time.
I hope this helps :)
1.0 mol of ethanol and 1.0 mol of acetic acid are dissolved in water and kept at 100 °C. The volume of the solution is 250 mL. At equilibrium, 0.25 mol of acetic acid has been consumed in producing ethyl acetate. Calculate Kc at 100 °C for the reaction C2H5OH(aq) + CH3CO2H(aq) CH3CO2C2H5(aq) + H2O(l)
Answer:
Kc = 0.333
Explanation:
First of all we state the equilibrium reaction:
C₂H₅OH(aq) + CH₃CO₂H(aq) ⇄ CH₃CO₂C₂H₅(aq) + H₂O(l)
Initially we start with 1 mol of alcohol and 1 mol of acid. After the reaction goes complete, 0.25 moles of acid have been consumed. As ratio is 1:1, we also consumed 0.25 moles of alcohol. Then, in the product side we finally produced 0.25 moles of water and 0.25 moles of ethyl acetate.
How many moles are available in the reactant side, after the equilibrium?
1 mol - 0.25 moles (that have been reacted) = 0.75 moles.
To determine Kc, we need molar concentrations, so let's see M in products and reactants:
0.75 mol / 0.25 L = 3 M
0.25 mol / 0.25 L = 1 M
We needed to convert 0.250 mL to L → 0.250 mL . 1L/ 1000mL = 0.250 L
Let's determine expression for Kc:
Kc = [H₂O] . [CH₃CO₂C₂H₅] / [C₂H₅OH] . [CH₃CO₂H]
1 . 1 / 3 . 3 = 1/9 → 0.333