(a) The edge length of the unit cell is 286 pm.
(b) The the density of aluminum metal is 1.27 x 10⁻²³ g/cm³.
What is edge length of the aluminum atom?
The edge length of the aluminum atom is calculated as follows;
a = 2r
where;
r is the radius of the atoma is edge lengtha = 2 x 143 pm = 286 pm
Volume of the aluminum atomV = a³
V = (286 x 10⁻¹²)³
V = 2.34 x 10⁻²⁹ m³
Density of the aluminum metalρ = ZM/VN
where;
Z is 4 for face-centered cubicM is mass of aluminum atom (g/mol), 26.982 amu = (1.66 x 10⁻²⁴ x 26.982) = 4.479 x 10⁻²³ g/molV is volumeN is Avogadro's numberρ = (4 x 4.479 x 10⁻²³) / ( 2.34 x 10⁻²⁹ x 6.023 x 10²³)
ρ = 1.27 x 10⁻¹⁷ g/m³
ρ = 1.27 x 10⁻¹⁷ g/m³ x (1 m³ / 10⁶ cm³)
ρ = 1.27 x 10⁻²³ g/cm³
Thus, the edge length of the unit cell is 286 pm and the the density of aluminum metal is 1.27 x 10⁻²³ g/cm³.
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Write the features of modern periodic table?
The long form of periodic table consist of vertical columns called groups and horizontal rows called periods.
Elements are arranged in the increasing order of atomic numbers.
Elements in the modern periodic table are arranged in 7 periods and 18 groups.
Horizontal rows are called periods and vertical columns are called groups.
Elements are placed in periods based on the number of shells in their atoms.
The shortest period is the first period which contains only two elements – Hydrogen and Helium.
Sixth period is considered as the longest periods in the periodic table. It contains elements from Cesium to Radon.
Seventh period is incomplete period.
In periodic table Lanthanides and Actinides are shown in the bottom of the periodic table
What is the oxidation number of nitrogen in nitrogen gas?
Group of answer choices
A. -2
B. -1
C. -3
D. 0
A 250 mL sample of gas is collected over water at 35°C and at a total pressure of 735 mm Hg. If the vapor pressure of water at 35°C is 42.2 torr, what is the volume of the gas sample at standard pressure?
Answer:
The volume of the gas sample at standard pressure is 819.5ml
Explanation:
Solution Given:
let volume be V and temperature be T and pressure be P.
[tex] V_1=250ml[/tex]
[tex] V_2=?[/tex]
[tex] P_{total}=735 mmhg[/tex]
1 torr= 1 mmhg
42.2 torr=42.2 mmhg
so,
[tex] P_{water}=42.2mmhg[/tex]
[tex] T_1=35°C=35+273=308 K[/tex]
Now
firstly we need to find the pressure due to gas along by subtracting the vapor pressure of water.
[tex] P_{gas}=P_{total}-P_{water} [/tex]
=735-42.2=692.8 mmhg
Now
By using combined gas law equation:
[tex]\frac{P_1*V_1}{T_1} =\frac{P_2*V_2}{T_2}[/tex]
[tex]V_2=\frac{P_1*}{P_2}*\frac{T_2}{T_1} *V_1[/tex]
[tex]V_2=\frac{P_gas}{P_2}*\frac{T_2}{T_1} *V_1[/tex]
Here [tex]P_2 \:and\: T_2[/tex] are standard pressure and temperature respectively.
we have
[tex]P_2=750mmhg \:and\: T_2=273K[/tex]
Substituting value, we get
[tex]V_2=\frac{692.8}{750}*\frac{273}{308} *250[/tex]
[tex]V_2= 819.51 ml[/tex]
what are the coefficients to balance Ag + Cu(NO3)2 = Cu + AgNO3
Answer:
See below
Explanation:
2 Ag + Cu(NO3)2 = Cu + 2 AgNO3
If the temperature of a gas is increased from 20°C to 35°C, what is the new pressure if the original pressure was 1.2 atm? Assume that volume is constant.
A. 0.6 atm
B. 1.3 atm
C. 1.0 atm
D. 2.6 atm
The new pressure of the gas would be = 2.1 atm.
Calculation of gas pressureThe initial temperature of the gas(T1) = 20°C
The final temperature of the gas(T2)= 35°C
The volume= constant
The Original pressure (P1) = 1.2atm
The new pressure (P2) =?
Using the gas law P1/T1 = P2/T2
Make P2 the subject of formula;
P2= P1×T2/T1
P2= 1.2 × 35/20
P2= 42/20
P2= 2.1 atm
Therefore, the new pressure of the gas would be = 2.1 atm.
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2Al(s)+Fe2O3(s) → Al2O(s)+2Fe(s) with a delta H=-847 KJ.
Railroad maintenance initiates a thermite reaction of 4.0 mol Al to connect two lengths of rail using the reaction above. How much heat is released during the reaction?
∆H for given reaction -847kJ
As it's negative reaction is exothermicSo
2 mol of Al releases 847KJ heat
4 mol Al releases
2(847)1694KJ∆H=-1694KJ
It is given that the energy released during the reaction of 2 moles of Al metal is - 847 KJ. The n the heat energy released by 4 moles of Al will be - 1694 KJ.
What is reaction enthalpy?The enthalpy change of a reaction is the heat energy absorbed or released by a reaction. For an endothermic reaction, the heat energy is absorbed and the enthalpy change is positive. For an exothermic reaction, where the energy is released, the enthalpy change will be negative.
The heat energy change during a reaction is equal to the product of mass, specific heat and temperature difference of the substanc eunder reaction or phase transition.
Given that, the heat evolved by 2 moles of Al is - 847 kJ. Then, the heat evolved when 4 moles of Al reacted is calculated as follows:
(4 × - 847) / 2 = - 1694 KJ.
Therefore, the heat energy released is - 1694 KJ.
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Question 2 of 10
What button on a scientific calculator is used to enter a number in scientific
notation?
Answer:
It's the button with the x, and a blank box above it.
Explanation:
Check the attachments, you'll see what it looks like. It will probably look different on your calculator, but the icon should be the same or similar.
ClO(4)− Express your answer as a chemical formula.
ClO(4)− is regarded as perchlorate ion and are produced commercially in most situations as salts via industries and in the laboratory.
What is Perchlorate ion?This ion is referred to as a monovalent inorganic anion and is obtained by deprotonation of perchloric acid. It is composed of chlorine and oxygen atoms in the ratio 1 to 4 respectively.
This has 32 valence electrons available in the Lewis structure and is used in the commercial production of solid rocket fuel.This ion has a molar mass of 99.451 g mol−1 and is used in different processes such as an oxidizer and to control static electricity during the process of food preservation in industries.
Therefore ClO₄− is also regarded as perchlorate ion and is the most appropriate choice.
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Magnesium metal burns with a bright white light . At the end of the reaction , white magnesium oxide powder is produced . Suggest why magnesium is often found in fireworks . Your answer should include a word equation .
The element magnesium is often in fireworks because it burns with bright white light. It adds white sparks and hence, improves the overall brilliance of a firework.
Properties of Magnesium Magnesium metal and its alloys are explosive in nature. They are highly flammable in pure form, powder form, or ribbon formMagnesium reacts violently with waterWhen magnesium metal is burned it reacts with the oxygen present in the air. Magnesium and oxygen react with each other to form magnesium oxide which is a white powder. Magnesium gives its 2 electrons to the oxygen to form this powdered product.The reaction is as follows:
[tex]2Mg (s) + O_2 (g) \rightarrow 2MgO(s) + energy[/tex]
The reaction is exothermic in nature.
It can also reduce water to H₂ gas[tex]Mg(s)+ 2H_2O \rightarrow Mg(OH)_2(s) + H_2 (g)[/tex]
Magnesium reacts with carbon dioxide to form carbon[tex]Mg(s)+CO_2 \rightarrow 2MgO(s)+ C(s)[/tex]
As magnesium is highly flammable and burns with white bright light, hence it is used in fireworks to improve its overall experience.
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Which of the following best describes how an ionic compound dissolves in water?
Group of answer choices
A. It separates into individual molecules and is a non-electrolyte.
B. It breaks into its individual ions and is an electrolyte.
C. It separates into individual molecules and is an electrolyte.
D. It breaks into its individual ions and is a non-electrolyte.
The correct answer choice which best describes how an ionic compound dissolves in water is that It breaks into its individual ions and is an electrolyte.
Option B is the correct answer
What is ionic bonding?This is type of chemical bonding which involves the transfer of valence electron from a metallic element to a non-metallic element
So therefore, The correct answer choice which best describes how an ionic compound dissolves in water is that It breaks into its individual ions and is an electrolyte.
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Which of the following statements is correct?
Question 12 options:
In an acidic solution, [H+] > [OH-].
In a basic solution, [OH-] > [H+] .
In a neutral solution, [H+] = [OH-] .
All of the above statements are correct.
Answer:
All of the above statements are correct.
Explanation:
acid is a substance that acts as a proton donor, so will have more H+ ions;
basic/alkaline substances act as a proton acceptor, so will have more OH- ions according to bronsted lowry theory
and no to mention neutral means balanced so will have balanced concentration of ions to cancel their charges out.
If a reaction is product favored, what can be said about the Equilibrium Constant of the reaction?
Group of answer choices
A. Negative
B. Equal to 1
C. Greater than 1
D. Less than 1
Answer:
C
Explanation:
more products are formed
If the pressure of 1.5 moles of a gas is 2 atm and the temperature is 27°C, what is the volume of the gas?
Group of answer choices
A. 9.25 L
B. 5.0 L
C. 37.0 L
D. 18.5 L
Answer:
D
Explanation:
Ideal gas law PV = n RT R = .082057 T must be in Kelvin
n = moles
V = n RT / P
= 1.5 (.082057) ( 27+ 273.15) / 2 = 18.5 liters
perform the following operation and express the answer in scientific notation 6x10^2 / 8x10^12
Answer:
7.5 x 10 ^-11
Explanation:
6/8 = .75
10^2 / 10^12 = 10^ (2-12) = 10^(-10)
so far .75 x 10^-10
which is 7.5 x 10^-11
In the reaction between CO and Fe3O4 , the theoretical yield in an experiment is calculated to be 47.2 g Fe.
When a chemistry student carries out the experiment, their actual yield is 34.1 g Fe.
Calculate the percent yield (% yield) of Fe
Answer:
Explanation:
34.1 / 47.2 x 100% = 0.07%
The percent yield (% yield) of Fe in a reaction with CO if the theoretical yield in the experiment is calculated to be 47.2 g Fe is 72.25%.
How to calculate percent yield?The percent yield is the percent ratio of the weight of the product obtained to the theoretical yield.
The percent yield can be calculated by dividing the experimental yield by the theoretical yield and multiplying the result by 100 then express the final answer in %.
According to this question, the experimental yield is 34.1g and the theoretical yield is 47.2g. The percent yield can be calculated as follows:
Percent yield = 34.1/47.2 × 100
Percent yield = 72.25%
Therefore, the percent yield (% yield) of Fe in a reaction with CO if the theoretical yield in the experiment is calculated to be 47.2 g Fe is 72.25%.
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4 Fe(s) + 3 02(g)
--> 2 Fe₂O3(s)
1. What is the oxidation state of iron (Fe) in the reactant Fe(s)?
2. What is the oxidation state of oxygen (O) in the reactant O2(g)?
3. What is the oxidation state of iron (Fe) in the product Fe2O3(s)?
4. What is the oxidation state of oxygen (O) in the product Fe2O3(s)?
5. In this reaction, iron is... (oxidized or reduced?)
6. In this reaction, oxygen is... (oxidized or reduced?)
7. What was the oxidizing agent in this reaction: Fe(s) or O2(g)?
The oxidation number of reactant Fe is 0 while the oxidation number of iron in the product is +3
What s a redox reaction?The term redox reaction implies a reaction in which there is an increase in the oxidation number of a specie and the decrease in the oxidation number of another specie.
Now we have the answers as follows;
1) The oxidation number of reactant Fe is 0
2) The oxidation number of reactant oxygen is 0
3) The oxidation number of iron in the product is +3
4) The oxidation number of oxygen in the product is -2
5). Iron is oxidized in the reaction
6) Oxygen is reduced in the reaction
7) The oxidizing agent in this case is the oxygen atom
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the weak ionization constant (Ka) for HNO2 is equal to:
Answer:
the answer is A
Explanation:
The weak ionization constant (Ka) for HNO₂ is:
[tex]\displaystyle K_a = \frac{[H^+][NO_2^-]}{HNO_2}[/tex]
What is the ionization constant?Acid-ionization constant Ka can be described as a quantitative measure of the strength of an acid in solution. It can be represented as the equilibrium constant for a chemical reaction:
[tex]{\displaystyle {\ce {HA \longrightarrow A^- + H^+}}}[/tex]
The chemical species HA can dissociate into A⁻ the conjugate base of the acid and a hydrogen ion, H⁺. In equilibrium, when the concentrations will not change over time, because both forward and backward reactions have the same rate.
The ionization constant can be described as the ratio of products and reactants raised to stoichiometric powers.
The dissociation constant is defined as:
[tex]{\displaystyle K_{\text{a}}=\mathrm {\frac {[A^{-}][H^{+}]}{[HA]}} }[/tex]
Given the dissociation of the HNO₂ as follows:
HNO₂ ⇄ H⁺ + NO₂⁻
The weak ionization constant (Ka) for HNO₂ is equal to:
[tex]\displaystyle K_a = \frac{[H^+][NO_2^-]}{[HNO_2]}[/tex]
Therefore, option A is correct.
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[05.01] How does the kinetic energy of a substance's particles in the solid phase compare to their kinetic energy in the liquid phase
Answer:
liquids have more kinetic energy than solids
Explanation:
water and ice are good examples
hotter the faster
kinetic can mean speed
solids held together by strong intermolecular forces of attraction
very little or no kinetic energy between the particles
solids are rigid and have definite shape and volume
liquid particles are held by weaker Vander Waal forces.
particles collide with each other and gain kinetic energy.
liquids have more kinetic energy than in the solid phase.
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In many regions of the world, humans rely on underground water supplies called aquifers for fresh water. The amount of water an aquifer can store depends in part on the porosity of the rock or sediment in which the water is stored. Porosity is a measure of the amount of liquid that can be stored in a material and is related to the amount of empty space that exists between individual rock or sediment particles. A group of civil engineers wants to determine whether the porosity of surface soil affects aquifer recharge rates-the ability of aquifers to refill with water. The engineers conduct the following study to determine the porosity of the surface soil at various locations. The results of the study will then be compared with the recharge rates of the aquifer each location supplies with water. 1. Collect one 200-milliliter (mL) sample of soil from each of three locations. 2. Place each soil sample in a beaker. 3. Add 200 mL of water to each sample and allow the water to saturate the soil. 4. Measure the amount of standing water in each beaker (amount of water the soil did not absorb). 5. Determine the amount of water in the soil sample by subtracting the amount of standing water from 200 mL. 6. Divide the amount of water in the soil sample by 200 mL and multiply by 100 to determine the percent porosity of the soil. Which change to the experimental design would improve the reliability of the engineers' measurements?
The change to the experimental design that would improve the reliability of the engineers' measurements is C. testing single samples from more than three locations
What is an experimental design?It should be noted that experimental design is the process of carrying out research in an objective as well as a controlled fashion in order for precision to be maximized and specific conclusions can be drawn from the hypothesis statement.
Based on the information, the locations selected are only three. Also, an area must have more types of soil with variable porosity. Hence, the collection of more soil samples may provide more accurate results than collecting soil samples from only three regions.
Therefore, change to the experimental design that would improve the reliability of the engineers' measurements is the testing single samples from more than three locations.
In conclusion, the correct option is C.
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Complete question:
Which change to the experimental design would improve the reliability of the engineers' measurements?
A. using a liquid other than water to determine porosity
B. using flasks instead of beakers
C. testing single samples from more than three locations
D. testing more samples from each location
what is s for silicon tetrachloride Sicl4?
S denotes the ''number of shared electron pairs by an atom'', Hence, Silicon transmits its 4 electrons with 4 Cl-atoms. Thus the Value of S is 4 in SiCl₄ .It is also known as covalency
What is silicon tetrachloride used for?
Silicon Tetrachloride is a transparent, colorless, fuming liquid with an irritating odor. It is used to create Silicon-containing chemicals and in chemical analysis. determine potentially hazardous frontages.
How is silicon tetrachloride produced?Silicon tetrachloride is designed by the chlorination of various silicon compounds such as ferrosilicon, silicon carbide, or mixtures of silicon dioxide and carbon. The ferrosilicon route is most familiar. In the laboratory, SiCl 4 can be prepared by dining silicon with chlorine on 600 °C (1,112 °F): Si + 2 Cl 2 → SiCl.
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If you rub a magnet over a metal screw driver, you can magnetize the screw driver. This is because the magnet
The magnet can cause the alignment of electron domains in the metal screw driver on rubbing, causing magnetism.
The magnetism in a permanent magnet is produced by magnetic moments of electrons in the magnet's constituent material. The material's atoms are each like tiny magnet bars. As a result of the quantum mechanical effect, the majority of these tiny magnets now prefer to align in a single direction to form domains, consequently magnetizing the entire substance.
Electrons exist in magnetic metals as well, although they are arranged differently. A strong magnet has a magnetic field strong enough to cause residual magnetism in the metal screwdriver by aligning the domains in it on rubbing with the metal.
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Need the answer pretttty pleaseeeeee
Answer:
The answer would be D.
Explanation:
Whenever one has many of the same correlating numbers within in a pattern, the rest tend to follow. With the information I was given and not the actual plotting, that would be my answer.
please solve this fast
what type of forces which exist in liquid hydrogen fluoride ?
Answer:
H-F is a polar covalent molecule in which dipole-dipole interactions exists
The average energy consumption for a new Samsung refrigerator is 5.47 × 10 2 kWh/ye ar. What is the average energy consumption of this refrigerator in gigajoules per day? (Given 1 GJ = 277.8 kWh ) show work.
Answer:
Explanation:
'nsofikldng[ousgafi'fjsngds[sbuofdia
The empirical formula for a compound is C3H3O the molecular mass is 110 what is its molecular formula
Answer:
emiprical formula is 55
Explanation:
(-^〇^-)
Write the balanced redox reaction Fe2+ and MnO4
Answer:
The balanced equation is 5Fe2++MnO-4+8H+→5Fe3++Mn2++4H2O .
Explanation:
˙˚ʚ(´◡`)ɞ˚˙
Answer:
5Fe2++MnO-4+8H+→5Fe3++Mn2++4H2O .
Explanation:
What is the difference between hydrogen bonds and covalent bond in relation to water structure
Answer:
Covalent bonds are intramolecular bonds whereas hydrogen bonds are intermolecular bonds.
hope this helps and good luck :)
Why is it important to dispose of waste chemicals in collection vessels, instead of pouring them down the
drain?
Explanation:
Reasons why you should not dispose of chemicals down drains
Pipes, especially older pipes, can leak at connections or where they have been damaged. Often large pipes, like storm water pipes or really large sewage mains, are made out of concrete so at places where two pipes meet, there can be minor leaks. It’s not a big deal when it’s just a little bit of storm water leaking, but if chemicals are also in this water, you’ve just given them a direct path to contaminating drinking water! Also, some of Indianapolis’s infrastructure is very old, and pipes used to be made out of things like bricks and hollowed out trees which will also leak.
Disposing of chemicals down drains can damage your plumbing which can be expensive to repair and also allow those chemicals a direct path into the groundwater.
Improperly disposing of chemicals at your site can lead to environmental contamination of your site which can be time consuming and expensive to clean up.
To answer this question, you may need access to the periodic table of elements.
Which of these pairs of atoms would experience a pure covalent bond?
a.) C and O
b.) Br and Br
c.) H and Cl
d.) Na and Cl
Answer:
b.) Br and Br
Explanation:
A covalent bond occurs when electrons are shared between two atoms causing them to form a bond.
A "pure" covalent bond refers to a nonpolar covalent bond. In these bonds, the electrons are shared equally between two atoms as a result of the absence of an (or very small) electronegativity difference. The purest covalent bond would therefore be between two atoms of the same electronegativity. Two bromines (Br) have the same electronegativity, thus making it the purest covalent bond.
Polar covalent bonds occur when electrons are shared unequally between two atoms. There is a larger electronegativity difference between the two atoms, but not large enough to classify the bonds as ionic. In this case, a.) and c.) are polar covalent bonds and d.) is an ionic bond.
