Answer:
4 electrons/atom
Explanation:
The conductivity of the lead σ = neμ where n = electron density, e = electron charge = 1.602 × 10⁻¹⁹ C and μ = electron mobility of lead = 2.3 cm²/(V·s) = 2.3 × 10⁻⁴ m²/(V.s)
Making n subject of the formula, we have
n = σ/eμ
Since σ = 4.90 × 10⁶ (Ω·m)⁻¹
Substituting the values of the variables into the equation, we have
n = σ/eμ
n = 4.90 × 10⁶ (Ω·m)⁻¹/(1.602 × 10⁻¹⁹ C × 2.3 × 10⁻⁴ m²/(V.s))
n = 4.90 × 10⁶ (Ω·m)⁻¹/(3.6846 × 10⁻²³ Cm²/(V.s))
n = 1.33 × 10²⁹ electrons/m³
We now find the number of moles of lead present in 1 m³ of lead.
So n' = ρ/M where ρ = density of lead = 11.4 g/cm³ = 11.4 g/cm³ × 10⁶ cm³/m³ = 11.4 × 10⁶ g/m³ and M = atomic weight of lead = 207 g/mol
So, n' = ρ/M
N = 11.4 × 10⁶ g/m³/207 g/mol
n' = 0.0551 × 10⁶ mol/m³
n' = 5.51 × 10⁴ mol/m³
Since n' = N/N' where N = number of atoms of lead in 1 m³ of lead and N = Avogadro's constant = 6.022 × 10²³ mol⁻¹
N = n'N' = 5.51 × 10⁴ mol/m³ × 6.022 × 10²³ mol⁻¹
N = 33.18 × 10²⁷ atoms/m³
N = 3.318 × 10²⁸ atoms/m³
So, the number of electron per atom is N" = n/N
= 1.33 × 10²⁹ electrons/m³ ÷ 3.318 × 10²⁸ atoms/m³
= 0.4 × 10¹ electrons/atom
= 4 electrons/atom
2x²=8.pls help me i really need it
Explanation:
2x²=8
x²=8/2
x=√4
x=2
hope it helps.
Answer:
[tex]\huge \fbox \pink {A}\huge \fbox \green {n}\huge \fbox \blue {s}\huge \fbox \red {w}\huge \fbox \purple {e}\huge \fbox \orange {r}[/tex]
[tex] {2x}^{2} = 8 \\ {x}^{2} = \frac{8}{2} \\ {x}^{2} = 4 \\ x = \sqrt{4} \\ x = 2[/tex]
ʰᵒᵖᵉ ⁱᵗ ʰᵉˡᵖˢ
[tex] \huge\purple{ \mid{ \underline{ \overline{ \tt ꧁❣ ʀᴀɪɴʙᴏᴡˢᵃˡᵗ2²2² ࿐ }} \mid}}[/tex]
One method of increasing the chances of particles colliding during a reaction is to...
1)decrease temperature
2) decrease concentration
3)increasing concentration
4)use a catalyst
Answer:
3
Explanation:
Increasing concentration
Solid AgCl (Ksp = 1.8 X 10-10) is placed in a beaker of water. After a period of time, the Ag+ concentration is measured and found to be 2.5 X 10-7 M.
a) What is the concentration of Cl-?
b) Has the system reached equilibrium?
c) Will more AgCl dissolve?
Explanation:
a)
[tex]k _{sp} = [Ag {}^{ + } ][Cl {}^{ - } ] \\ but \: [Ag {}^{ + } ] = [Cl {}^{ - } ] \\ k _{sp} = [Ag {}^{ + } ] {}^{2} \\ [Ag {}^{ + } ] = \sqrt{k _{sp}} \\ = \sqrt{1.8 \times {10}^{ - 10} } \\ = 1.34 \times {10}^{ - 5} mol {dm}^{ - 3} [/tex]
b)
It has not reached equilibrium because the silver concentration is not yet equal to the value of Ksp.
c)
Yes it will dissolve in order to establish the equilibrium.
3. At 34.0°C, the pressure inside a nitrogen-filled tennis ball with a volume of 148 cm3 is 212
kPa. How many moles of N2 are in the tennis ball?
Answer:
0.0123 mol
Explanation:
Step 1: Convert 34.0 °C to Kelvin
We will use the following expression.
K = °C + 273.15 = 34.0 + 273.15 = 307.2 K
Step 2: Convert 148 cm³ to L
We will use the conversion factors:
1 cm³ = 1 mL1 L = 1000 mL[tex]148cm^{3} \times \frac{1mL}{1cm^{3}} \times \frac{1L}{1000mL} = 0.148L[/tex]
Step 3: Convert 212 kPa to atm
We will use the conversion factor 1 atm = 101.325 kPa.
212 kPa × 1 atm / 101.325 kPa = 2.09 atm
Step 4: Calculate the moles of nitrogen gas
We will use the ideal gas equation.
P × V = n × R × T
n = P × V / R × T
n = 2.09 atm × 0.148 L / (0.0821 atm.L/mol.K) × 307.2 K = 0.0123 mol
why do we have to write the background of the study
Answer:
Writing down background information can help you to remember what you learned and can be used for notes in the future when taking an assessment.
Explanation:
Can I get brainliest? It's for a challenge
The chemical reaction between water and magnesium is?
Answer: hydrogen gas
Explanation: When magnesium interacts with water, it will form a hydrogen gas that ignites violently due to the excessive heat and oxygen supply.
ch3-co-ch2-ch2-ch3 IUpAC name
Answer:
2-pentanone.
Explanation:
Hello there!
In this case, for the given compound and, in agreement with the octet rule, it is possible to realize that the CO is actually C=O as shown below:
CH3 - C - CH2 - CH2 - CH3
||
O
Thus, since the C=O stands for the carbonyl group within the parent chain, we infer this is a ketone and more specifically 2-pentanone as it has five carbon atoms.
Regards!
PLEASE HELP!! NO LINKS PLEASE REAL ANSWER!!!!!
What will be volume of 20.0 g of CH4 gas at a pressure of 0.950 atm and temperature of 21.0 oc?Question 1 options:
A. 21.8 L
B. 31.8 L
C. 2.27 L
D. 4.27 L
What happens to iron when it melts?
O A. It undergoes a chemical change.
O B. It undergoes a physical change.
O c. Its atoms break apart and form new atoms.
O D. Its atoms combine and form new atoms.
Answer:
B. It undergoes a physical change.
Explanation:
Hello there!
In this case, since we know that chemical changes lead to the formation of new atoms and/or compounds due to the bonds rearrangement of the initial substances and the physical changes occur without changing the composition of the initial substances, we can infer that, since melting is a process that changes the phase of matter from solid to liquid without changing the identity of the initial substance, the answer to this question would be B. It undergoes a physical change. because the other options describe chemical changes.
Best regards!
Answer:
B. It undergoes a physical change.
Explanation:
At room temperature, the iron atoms are in an unusual loosely packed open arrangement; as iron is heated past 912 degrees Celsius, the atoms become more closely packed before loosening again at 1,394 degrees Celsius and ultimately melting at 1,538 degrees Celsius.
Given the reaction: N2(g) +2O2(g) ⇌ 2NO2(g) The forward reaction is endothermic. Determine which of the following changes would result in more product being produced.
I. Increase NO2
II. Decrease O2
III. Add a catalyst
IV. Increase the temperature
V. Increase the pressure
A. I and II
B. II, III, and V
C. IV and V
D. II and IV
Answer:
C
Explanation:
increasing the temperature will favour the forward reaction therefore the reaction system will try to counteract that by producing more heat and NO2 therefore increases the amount of products produced
increasing the pressure will favour the forward reaction as it has more moles of substance therefore if the forward reaction is favored, more product will be produced
Answer:
C.) lV and V
Explanation:
I got it correct on founders edtell
Why do scientist conduct experiments on animals?
Answer:
Animals are used in scientific research to help us understand our own bodies and how they work. This is necessary to develop new medicines. Animals are also used to safety test potential medicines before they are tested in people and to check the safety of other chemicals.
Explanation:
Help solve the types of chemical reactions
[tex]1) \: decomposition[/tex]
[tex]2) \:hydrocarbon \: combustion[/tex]
[tex]3) \: formation[/tex]
[tex]4) \: double - replacement[/tex]
[tex]5 \: double - replacement[/tex]
[tex]6) \: formation[/tex]
[tex]7)double \: - replacement[/tex]
[tex]8) \: double - replacement[/tex]
Name: ___________________________ Date: __________ Period: ______ Solubility Rules Practice Worksheet Name or give the chemical formula for each of the following compounds. State whether they are soluble (will dissolve) or insoluble (will not dissolve) in solution. Use solubility rules. Chemical Formula Name Solubility NH4OH Ra(OH)2 Nickel (III) Acetate CsOH RbCl Potassium Phosphate MgS CaI2 Gold (II) Hydroxide Li3PO4 Platinum (II) Carbonate Barium Nitrate
1. Watch how the solubility of a gas changes as pressure is increased and then decreased during the run. Which of the following statements correctly explain the relationship between the solubility of a gas and its pressure?
A. As pressure decreases, the concentration of gas molecules in the solution increases.
B. The concentration of gas particles in the solution is higher at 4.25 atm than at 1.00 atm.
C. The solubility of a gas decreases with a decrease in pressure.
D. The solubility of nitrogen gas at 2.00 atm is twice the solubility of the gas at 1.00 atm.
E. Fewer gas molecules are soluble at higher pressures.
F. More gas molecules are soluble as pressure is increased.
G. As pressure is increased, the rate at which gas molecules enter the solution decreases.
2. At a certain temperature, the solubility of N2 gas in water at 3.08 atm is72.5mg of N2 gas/100 g water. Calculate the solubility of N2 gas in water, at the same temperature, if the partial pressure of N2 gas over the solution is increased from 3.08 atm to 8.00 atm .
Answer:
A. As pressure decreases, the concentration of gas molecules in the solution increases.
D. The solubility of nitrogen gas at 2.00 atm is twice the solubility of the gas at 1.00 atm.
F. More gas molecules are soluble as pressure is increased.
The solubility is 188.3 mg of N2 gas/100 g water.
Explanation:
As the pressure on the gas decreases, the volume of gas molecules in the solution increases due to having distance from each other. The solubility of nitrogen gas at 2.00 atm is twice the solubility of the gas at 1.00 atm because there is more pressure on the gas molecules so due to more compression, the gas becomes more soluble. More gas molecules are soluble as pressure is increased. The solubility is 188.3 mg of N2 gas/100 g water if the atmospheric pressure is increases from 3.08 atm to 8.00 atm. This value is calculated with the help of formula i.e. P2/P1 = S2/S1.
The air we breathe contains different individual gases (mostly nitrogen and oxygen). Which of the following correctly describes the air we breathe? A. mixture B. liquid C. compound D. element
Answer:
A. Mixture
Explanation:
Our air has a group of gases. For example, you said nitrogen & oxygen, Which is significantly a mixture.
The volume of a sample of carbon dioxide gas is 26.42 L at 73.0°C. What will its volume be at 92.0°C at constant pressure?
Answer:
[tex]V_2=27.87L[/tex]
Explanation:
Hello there!
In this case, according to the given information, it turns out possible for us to solve this problem by using the Charles' law a directly proportional relationship to understand the volume-temperature behavior:
[tex]\frac{V_2}{T_2} =\frac{V_1}{T_1}[/tex]
Thus, we solve for the final volume, V2, and make sure the temperature are in Kelvin as shown below:
[tex]V_2 =\frac{V_1T_2}{T_1} \\\\V_2=\frac{26.42L(92+273.15)K}{(73+273.15)K} \\\\V_2=27.87L[/tex]
Regards!
Jim makes a mixture which contains 10 mg of salt, 30 mg of sand, and some iron filings. The total mass of the mixture is 100 mg
Which amount of iron filings does Jim use in the mixture?
A10
B30
C40
D60
Answer:
Amount of iron fillings in mixture = 60 mg
Explanation:
Given:
Total mass of mixture = 100 mg
Amount of salt in mixture = 10 mg
Amount of sand in mixture = 30 mg
Find:
Amount of iron fillings in mixture
Computation:
Using Law of Conservation of mass;
Total mass of mixture = Amount of salt in mixture + Amount of sand in mixture + Amount of iron fillings in mixture
100 = 10 + 30 + Amount of iron fillings in mixture
100 = 40 + Amount of iron fillings in mixture
Amount of iron fillings in mixture = 100 - 40
Amount of iron fillings in mixture = 60 mg
please help- science
1. - new
2. full
3. first quarter
4. last quarter
Answer:
2. Full
Explanation:
A lunar eclipse occurs at a full moon when Earth is directly between the moon and the sun. During a lunar eclipse, Earth blocks sunlight from reaching the moon.
Hope this helps!!
hydrogen chloride, hydrogen nitrate (v), sodium chloride, sodium hydroxide. Name a substance known as common salt
Answer:
C: Sodium chloride
Explanation:
Common salt is gotten when sodium atoms reacts with chlorine atoms in an exothermic reaction to form an ionic substance known as sodium chloride with the chemical formula NaCl.
Equation is;
2Na + Cl2 = 2NaCl
Looking at the options, the correct one is Sodium chloride.
When sodium chloride is dissolved in water, the freezing point of water _________. A. increases B. first increases, then decreases C. does not change D. decreases
The presence of a non-volatile salt will decrease the freezing point of water and this process is called depression in freezing point. Thus option D is correct.
What is freezing point?Freezing point of a substance is the temperature at which it converts from its liquid state to solid state where, both the states are in equilibrium. Freezing point of water is zero degree celsius.
The freezing point of a solvent depends on some parameters such as the bond type, molecular weight, temperature, pressure etc.
When a non-volatile solute is added to the solvent its freezing point decreases from its initial value. Because presence of non-volatile salts will affect the intermolecular attraction and thereby the energy that must be applied to freeze the compound.
Therefore, the freezing point of water decreases, when sodium chloride is added into it. Thus option D is correct.
To find more about freezing point, refer the link below;
https://brainly.com/question/2292439
#SPJ6
Write in exponential form: 34⋅34⋅34⋅34⋅34⋅34⋅34⋅34.
Answer:
34^8
Explanation:
Suppose you needed to explain the concept of the mole to a junior high school student. What would you tell them?
Answer:
Explanation:
duehgjvcujhyeq bvckjfdsaeb gjdksghUIBGREQWMNHGTRE BAGTFEQA
Which of the compounds shown are structural
isomers of this compound? Check all that apply.
A
B
С
D
Answer:
A & C
Explanation:
The next one is A Edge 2022
The compound which are the structural isomers of the given compound is compound A & C.
What are structural isomers?Structural isomers are those isomers in which which are having the same molecular formula but different structural structures.
Compound A: A is the structural isomer of the given compound as they both have same number of carbon and hydrogen atoms present in that.Compound B: B is not the structural isomer of the given ompound as they have not equal number of carbon and hydrogen atoms in it.Compound C: C is the structural isomer of the given compound as they both have same number of carbon and hydrogen atoms present in that.Compound D: D is not the structural isomer of the given ompound as they have not equal number of carbon and hydrogen atoms in it.Hence A & C are the structural isomers of given compound.
To know more about structural isomers, visit the below link:
https://brainly.com/question/26298707
How many grams water will condense when 56,500 joules of energy is removed from steam at its boiling point
Answer:
Start your streak by answering any question. You'll get bonus points from day 2.
n today's experiment, Solutions A and B are prepared as follows. Solution A: Solution B: 2.0 mL of 3.00 x 10-4 M bromcresol green 2.0 mL of 3.00 x 10-4 M bromcresol green 5.0 mL of 1.60 M acetic acid (HAc) 2.0 mL of 0.160 M sodium acetate (NaAc) 2.0 mL of 0.200 M KCl diluted to a total volume of 50 mL diluted to a total volume of 50 mL How many mL of Solution A must be added to Solution B to give a buffer that is equimolar in HAc and Ac-
Answer:
2 mL of Solution A must be added to Solution B to give a buffer that is equimolar.
Explanation:
Given the data in the question;
First we determine the number of sodium acetate;
⇒ molarity × volume ( L )
⇒ 0.16 × 2.0 mL
⇒ 0.16 × 0.002 L
⇒ 0.00032
Now, Molarity of sodium acetate = moles / Volume(L)
⇒ ( 0.00032 / 50 ) × 1000
⇒ 0.0064
Since number of moles of acetic acid that should be added tp make equimolar solution is 0.00032
and Molarity of acetic acid is 0.16 molL⁻¹
Let X represent the volume that should be added.
so;
Molarity = Moles / Volume (L)
we substitute
0.16 = (0.00032 / X) × 1000
0.16 = 32 / X
X = 0.32 / 0.16
X = 2 mL
Therefore, 2 mL of Solution A must be added to Solution B to give a buffer that is equimolar.
What locations are likely to be affected by an earthquake or tsunami?
San Francisco, California, USA
San Francisco, Tokyo, and Asunción
Tokyo, Japan
None of the locations
Asunción, Paraguay, South America
Answer:
All the locations can suffer earthquakes and a handful like tokyo tsunami so the question is either or so the anwer would be all
Explanation:
help me with questions 6,11,15,16 and 17 please
ayúdame con las preguntas 6,11,15,16 y 17 por favor
A cylindrical rod of copper (E = 110 GPa) having a yield strength of 240 MPa is to be subjected
to a load of 6660 N. If the length of the rod is 380 mm, what must be the diameter to allow an
elongation of 0.50 mm?
Answer:
required diameter is 7.65 mm
Explanation:
Given the data in the question;
F = 6660 N
l₀ = 380 mm = 0.38 m
E = 110 GPa = 110 × 10⁹ N/m²
Δl = 0.50 mm = 0.0005 m
So, lets assume the deformation is elastic;
d₀ = √( [4l₀F] / [πEΔl] )
we substitute
d₀ = √( [4 × 0.38 × 6660] / [π × (110 × 10⁹) × 0.0005]] )
d₀ = √( 10123.2 / 172787595.947 )
d₀ = √( 5.85875 × 10⁻⁵ )
d₀ = 0.007654 m
d₀ = ( 0.007654 × 1000 )mm
d₀ = 7.65 mm
Therefore, required diameter is 7.65 mm
PLEASE HELP REAL ANSWER NO FILE. Part A
Electricity generated from any source comes with its own advantages and
disadvantages. So, no source of energy for generating electricity is perfect. However,
imagine that there is an energy source that perfectly meets the needs of society.
Describe this ideal source of energy. Include relevant factors such as cost, supply, safety,
reliability, and environmental impact
Answer:
Wind energy
Explanation:
An ideal source of energy needs to be reliable, cost effective, safe and must lead to almost zero adverse environmental impact.
Wind energy is energy obtained from air moving at high velocity. This energy is harvested using windmills which convert mechanical energy to electrical energy.
Wind is inexpensive because it occurs naturally. However, a large expanse of land is required in order to mount sufficient number of windmills that will generate enough electrical energy for practical purposes.
This method of electricity generation is safe and does not lead to any environmental hazard unlike the burning of fossil fuels, use of nuclear energy or loss of habitat due to hydroelectric power generation.
What are the substances that interact to form new substances in a chemical reaction called?
A. Reactants
B. Products
C. Chemicals
D. Substances
Answer:
A. Reactants
Explanation:
A chemical reaction is the process in which atoms present in the starting substances rearrange to give new chemical combinations present in the substances formed by the reaction. These starting substances of a chemical reaction are called the reactants, and the new substances that result are called the products.