Answer:
(a) The unit cell edge length 0.421 nm
Explanation:
Lets calculate -:
Given -
density = [tex]3.58g/cm^3[/tex]
Molecular weight of MgO = 24.31 +16
[tex]40.13 g/mole[/tex]
Avagadro number = [tex]6.022\times10^2^3[/tex]
In rock salt structure , there are four anions and four cations , hence Z=4 (Number of formula per unit cell)
Now, using the formula -
[tex]d=\frac{ZM}{N_Aa^3}[/tex]
[tex]a=[\frac{ZM}{N_Ad}]]^\frac{1}{3}[/tex]
Now, putting the given values
[tex]a=\frac{4\times40.13g/mole}{6.022\times10^2^3\times(3.58g/cm^3)}[/tex]
[tex]4.21\times10^-^8 cm[/tex]
= 0.421 nm
Hence , the unit cell edge length = 0.421 nm
The unit cell edge length of magnesium oxide (MgO) is equal to 0.421 nanometer.
Given the following data:
Density = 3.58 [tex]g/cm^3[/tex]Atomic weight of magnesium = 24.31 g/mol.Atomic weight of oxygen = 16.00 g/mol.Scientific data:
Avogadro's number = [tex]6.02 \times 10^{23}[/tex]Z for FCC = 4Molar mass of magnesium oxide (MgO) = [tex]24.31 + 16 = 40.31 \;g/mol.[/tex]To determine the unit cell edge length:
Mathematically, the unit cell edge length for a face-centered cubic (FCC) structure is given by the formula:
[tex]a=\sqrt[3]{\frac{ZM}{\rho N_A} }[/tex]
Where:
Z is the number of atoms per unit cell.[tex]\rho[/tex] is the density.M is the molar mass.[tex]N_A[/tex] is the Avogadro constant.Substituting the given parameters into the formula, we have;
[tex]a=\sqrt[3]{\frac{4 \; \times \;40.31}{3.58\; \times \;6.02 \times 10^{23}} }\\\\a=\sqrt[3]{\frac{161.24}{2.16 \times 10^{24}}}\\\\a=\sqrt[3]{7.47 \times 10^{-23}} \\\\a=4.21 \times 10^{-8}\;meter[/tex]
Note: [tex]1 \;nanometer = 1 \times 10^{-9} \;meter[/tex]
a = 0.421 nanometer.
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I need help please!!
Answer:
BECAUSE OF DENSITY
Explanation:
Answer:
It's DENSITY
Explanation:
YOURE WELCOME
Find [H+] of a 0.056 M hydrofluoric acid solution. Ka = 1.45 x 10-7
Answer: [tex][H^+][/tex] of 0.056 M HF solution is [tex]8.96\times 10^{-5}[/tex]
Explanation:
[tex]HF\rightarrow H^+F^-[/tex]
cM 0 0
[tex]c-c\alpha[/tex] [tex]c\alpha[/tex] [tex]c\alpha[/tex]
So dissociation constant will be:
[tex]K_a=\frac{(c\alpha)^{2}}{c-c\alpha}[/tex]
Give c= 0.056 M and [tex]\alpha[/tex] = ?
[tex]K_a=1.45\times 10^{-7}[/tex]
Putting in the values we get:
[tex]1.45\times 10^{-7}=\frac{(0.056\times \alpha)^2}{(0.056-0.056\times \alpha)}[/tex]
[tex](\alpha)=0.0016[/tex]
[tex][H^+]=c\times \alpha[/tex]
[tex][H^+]=0.056\times 0.0016=8.96\times 10^{-5}[/tex]
Thus [tex][H^+][/tex] of 0.056 M HF solution is [tex]8.96\times 10^{-5}[/tex]
Burning is a reaction in which oxides are formed by combining ______ and _________.
Answer:
Burning is a reaction in which oxides are formed by combining fuel(reductant) and oxidant.
Explanation: Ex charcoal and lighter fluid
Hope this helps
1. A sample of oxygen gas has a volume of 150 ml when its pressure is 440 mmHg. If the pressure is
Increased to standard pressure and the temperature remains constant, what will the new volume be?
Answer:86.84
Explanation:
help please. What type of reaction is this: barium nitrate --> barium oxide + nitrogen dioxide + oxygen
Answer:
Decomposition Reaction
Explanation:
Ba(NO₃)₂(s) ⇒ BaO(s) + N₂(g) + 3 O₂(g)
Barium nitrate decomposes into the chemical species that were used to create it.
Which of the following is a FALSE statement? *
A. Heat moves through solids by by conduction.
B. Molecules move faster in warmer substances.
C. Warm water is denser than cold water.
D. Heat moves through liquids and gases by convection.
Answer:
C: Warm water is denser than cold water
30g of Aluminum at 80°c is added to 30g of water at 10°c . Predict
the final temperature of the water
Answer:
the explanation of this 20
Explanation:
20 c
Waves made by the breeze were very different than wave created by speedboat. describe the difference
Answer:
The amplitude of the speedboat waves were larger then the Breeze waves. The frequency of the speedboats waves were lower than the breeze waves. the speedboat waves had more of an effect on the boat, which tells us the speedboat waves had more energy.
Explanation:
plz can i get brainliest:)
Answer:
speedboat waves artificail and waves by breezes natural
Explanation:
Groups of atoms repeat to make up a substance?
True
False
Answer:
ITS TRUE!!!!!
What does it mean to say that scientific models are open to change? (2 points)
a
Scientific models are usually not very accurate.
b
Scientific models can be adjusted when new information is found.
c
People can adjust scientific models to fit their personal beliefs.
d
Experimental results can be changed to fit the accepted model
What would be the most effective way for a scientist to get an idea of the actual age of a rock?
Answer:
Radiometric dating
Explanation:
Radiometric dating would be the most effective way since it is a technique that can establish the age of objects older than a few thousand years.
How much water needs to be added
to 55 mL of 3.0 M stock solution to
produce a .75 M solution?
Answer:
165 ml
Explanation:
We are given;
Initial volume; V_a = 55 ml
Initial molarity; M_a = 3 M
Molarity of desired solution; M_b = 0.75 M
Volume of desired solution; V_b = (55 + x) ml
Where x is the volume of water to be added.
To solve for V_b, we will use the equation ;
M_a•V_a = M_b•V_b
V_b = (M_a•V_a)/M_b
V_b = (3 × 55)/0.75
V_b = 220 mL
Thus;
(55 + x) = 220
x = 220 - 55
x = 165 mL
Answer:
gotta concert mL to L
3.0=mol/0.055( you multiply morality and liter)
0.165 mol
you divide the mole by the other given molarity
0.165/0.75= 0.22 L
0.22 *1000= 220 mL
Explanation:
In a heat engine, 500 J of heat enters the system, and the piston does 300 J of work. What is the final internal (thermal) energy of the system if the initial energy is 1500 J?
200 J
800 J
1300 J
1700 J
Answer:
200J
Explanation:
This is because 500J - 300J = 200J
I hope this helps!!!
Answer:
1700 Joules. I Took the test.
Explanation:
Hello Friends Can Yall Plz Help Me For Brainliest Don’t Comments No B.S Yu Will Get Cursed out show ya work
Answer:
it is b
Explanation:
mid ocean ridge diverges meaning it moving in two different direction horizontally - left to right
Explain how scientists study the Earth’s interior. PLEASE HELP :))))!
Answer:
Scientists study Earth's interior by studying
seismic waves. Seismic waves are waves of energy that travel
through Earth.
Explanation:
My teacher didn’t explain this. Please Help Me!!
Due to their low melting points nitrogen oxygen and helium are examples of which type of matter when at room
temperatures?
A. Gas
B.liquid
C.Plasma
D. Solid
An unknown piece of metal absorbs 1350 J of heat as 55.0 g of the metal heats up from 20.0 oC to 47.0 oC
Answer:
[tex]C=0.91\frac{J}{g\°C}[/tex]
Explanation:
Hello there!
In this case, according to the given information, it is possible to recall the equation to calculate the heat, Q, in these calorimetry problems as shown below:
[tex]Q=mC(T_f-T_i)[/tex]
Thus, given the absorbed heat, mass and temperatures, we can easily calculate the specific heat of the metal as shown below:
[tex]C=\frac{Q}{m(T_f-T_i)}[/tex]
Then, by plugging in we obtain:
[tex]C=\frac{1350J}{55.0g(47.0\°C-20.0\°C)} \\\\C=0.91\frac{J}{g\°C}[/tex]
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Answer:
C
Explanation:
increasing T (knowledge of direct proportion and Inverse proportion)
Question 19 (3 points)
If the density of the earth was 11.0 g/mL instead of its measured value of 5.51 g/mL, the force of gravity would
be twice what it is at sea level. If the earth's density was twice than its actual density, then in pounds per
square inch at sea level the earth's atmosphere in British units would be equal to:
a) 7.35 psi b) 14.7 psi c ) 29.4 psi d) 44.1 psl e) 98.8 psi
Answer:
c ) 29.4 psi
Explanation:
If the density of earth was twice than its actual density which is 5.51 g/mL, then at sea level the atmospheric pressure of earth in British units would be equal to 29.4 psi because increase of gravity, increase occurs in the atmospheric pressure. If we double the gravity of earth by double of the earth density, so the weight of that same mass of air will be double which leads to the doubling of the atmospheric pressure at the sea level.
A gaseous mixture contains 5.0 moles of nitrogen and 10.0 moles of helium . What is the total pressure if the temperature is 25 degrees C and the volume is 3.0 L? a) 122 atm
B) 56 atm
d) 2.0 atm
C)3.0 atm
Answer:
A) 122 atm
Explanation:
PV = nRT
Solve for P --> P = nRT/V
n = 10.0 mol + 5.0 mol = 15.0 mol
R = 0.08206 L atm / mol K
T = 25 + 273 = 298 K
V = 3.0
P = (15.0)(0.08206)(298) / (3.0) = 122 atm
A boy is skating down the street, hits a curb, and files off the board. Why did this happened? Can y’all plz help me it’s due today!
Answer:
to much sause
Explanation:
NEED HELP ASAP
You need to prepare a 100. mL of a 0.050M solution of CaCl2. How many grams of CaCl2 are needed?
Answer:
9.
Explanation:
.
A lake has been infected by some type of new algae that is unknown. Every single day the amount of surface area that the algae takes up doubles. Day 1 has a certain amount, day 2 it is 2x that amount. It takes 87 days for the entire lake to be overrun by this new algae. How many days does it take to cover half of the lake? Show your work and explain your thinking. In science we need to be able to justify our answers.
hint: It is not the "obvious" answer.
Answer:
It takes 86 days take to cover half of the lake
Explanation:
In the day #1, the amount of the algae is X,
In the day #2 is 2X
In the day #3 is 2*2*X = X*2²
...
In the day #n the amount of the algae is X*2^(n-1)
Assuming X = 1m³. In the day 87, the area infected was:
1m³*2^(87-1)
7.74x10²⁵m³ is the total area of the lake
the half of this amount is 3.87x10²⁵m³
The time transcurred is:
3.87x10²⁵m³ = 1m³*2^(n-1)
Multiplying for 5 in each side:
ln (3.87x10²⁵) = ln (2^(n-1))
58.9175 = n-1 * 0.6931
85 = n-1
86 = n
It takes 86 days take to cover half of the lakeWhich of the following statements is not true? a. Water is polar. b. Water stabilizes temperature. c. Water is essential for life. d. Water is the most abundant atom in Earth’s atmosphere.
Answer: d. Water is the most abundant atom in Earth’s atmosphere.
Explanation:
Water percentage in the atmosphere is 0.001 percent only as it not the major reservoir or source of water. The water is available in the atmosphere in the form of water vapors. These water vapors when aggregate and their concentration becomes high they fall down as rain on earth so the rain is collected in water reservoirs like oceans, rivers, lakes, ponds, aquifers, and other sources of water, which are the components of hydrosphere on earth. So, hydrosphere is most abundant in water. Moreover, water is not an atom instead it is the molecule formed by the combination of two molecules of hydrogen and one molecule of oxygen.
HCl (aq) + NaOH (aq) = NaCl (aq) + H2O (l)
What type of reaction is the above?
Answer:
Neutralization reaction
Explanation:
It is a reaction between an acid and a base
Balance C12H22011 → C + H2
Answer:
What is this?
Explanation:
Put the following in order from largest to smallest.
Chromosome, gene, nucleus, cell, DNA
Answer:
cell, nucleus , chromosome, DNA, gene
Look at the following enthalpy diagram. Select all that apply.
1. The products have more energy than the reactants.
2. This is an addition reaction.
3. A large activation energy is required for this reaction to take place.
4.The products are more stable than the reactants.
5. This is a substitution reaction.
Answer:
Option 2 and 4 are correct
Explanation:
The reactants in the attached image have more enthalpy and hence less stability as they are more reactive. Thus, Product is more stable than the reactants.
This is an addition reaction in which two reactants add up to form the product.
Very less activation energy is required as the reactants themselves are unstable, possess high energy and hence are very reactive.
Reactants have more energy than the products.
You have a hydrate of compound X that is 60.26g. You heat the hydrate, allow it to cool, and then remass it. The new mass is 23.0g. The molar mass of compound X as an anhydrate is 100 g/mol.
Answer:
100gmol
Explanation:
Explain ways humans can reduce global warming. Use 4-5 complete sentences.
pls show your work thx
Explain ways humans can reduce global warming
The list of ways humans can reduce global warming includes: driving affordable electric cars, increasing the use of wind and solar energy in communities, and reducing water waste like plastic bottles. Greenhouse gases in the atmosphere cause global warming and air pollution. Also, reducing wastage that affects our soil benefits agriculture and freshwater locations. Conserve energy by turning off your lights, walking or riding your bicycle, and invest in solar energy. Solar energy can decrease greenhouse gas emissions in our air that we beathe! Affordable solar energy helps the enviorment and poorer communites with reducing air pollution.