Answer:
3900 mol Pb
General Formulas and Concepts:
Chemistry - Atomic Structure
Reading a Periodic TableUsing Dimensional AnalysisExplanation:
Step 1: Define
8.1 × 10⁵ g Pb
Step 2: Identify Conversions
Molar Mass of Pb - 207.2 g/mol
Step 3: Convert
[tex]8.1 \cdot 10^5 \ g \ Pb(\frac{1 \ mol \ Pb}{207.2 \ g \ Pb} )[/tex] = 3909.27 mol Pb
Step 4: Check
We are given 2 sig figs. Follow sig fig rules and round.
3909.27 mol Pb ≈ 3900 mol Pb
Look at picture and answer will mark brainliest.
Answer:
A
Explanation:
calculate the mass percent of water in CaCrO4.H2O
Answer:
10.35%
Explanation:
Find the molar mass of water, using your periodic table: 18.02 g. Then find the molar mass of the total substance: 174.10 g.
Divide the molar mass of water by the molar mass of the total substance and multiply 100%. Doing this, you get 10.35%.
A rigid, 28-L steam cooker is arranged with a pressure relief valve set to release vapor and maintain the pressure once the pressure inside the cooker reaches 150 kPa. Initially, this cooker is filled with water at 175 kPa with a quality of 10 percent. Heat is now added until the quality inside the cooker is 40 percent. The water is stirred at the same time that it is being heated. Determine the minimum entropy change of the heat-supplying source if 100 kJ of work is done on the water as it is being heated. Use steam tables.
Answer:
[tex]\Delta S_{source}>-1.204\frac{kJ}{K}[/tex]
Explanation:
Hello!
In this case, given the initial conditions, we first use the 10-% quality to compute the initial entropy:
[tex]s_1=s_{f,175kPa}+q*s_{fg,175kPa}\\\\s_1=1.4850\frac{kJ}{kg*K} +0.1*5.6865\frac{kJ}{kg*K}=2.0537\frac{kJ}{kg*K}[/tex]
Now the entropy at the final state given the new 40-% quality:
[tex]s_2=s_{f,150kPa}+q*s_{fg,150kPa}\\\\s_2=1.4337\frac{kJ}{kg*K} +0.4*5.7894\frac{kJ}{kg*K}=3.7495\frac{kJ}{kg*K}[/tex]
Next step is to compute the mass of steam given the specific volume of steam at 175 kPa and the 10% quality:
[tex]m_1=\frac{0.028m^3}{(0.001057+0.1*1.002643)\frac{m^3}{kg} } =0.274kg\\\\m_2=\frac{0.028m^3}{(0.001053+0.4*1.158347)\frac{m^3}{kg} } =0.0603kg[/tex]
Then, we can write the entropy balance:
[tex]\Delta S_{source}+\frac{Q}{T_1} -\frac{Q}{T_2} +s_2m_2-s_1m_1-s_{fg}(m_2-m_1)>0[/tex]
Whereas sfg stands for the entropy of the leaving steam to hold the pressure at 150 kPa and must be greater than 0; thus we plug in:
Which is such minimum entropy change of the heat-supplying source.
Best regards!
solve the equation:
1) 3,2 m²= x dm²= x cm²
BRAINLIEST!!!!
Answer:
sin = (330)
csc = (60)
−4 = cot (−45)
Explanation:
im not sure what you were looking for, make me brainlest please?
Determine the oxidation number of chlorine in CI2 with the steps
Answer: The oxidation number of chlorine in [tex]Cl_2[/tex] is zero
Explanation:
Oxidation number or oxidation state : It represent the number of electrons lost or gained by the atoms of an element in a compound.
Rules for Oxidation Numbers are :
1. The oxidation number of a free element is always zero.
2. The oxidation number of a monatomic ion equals the charge of the ion.
3. The oxidation number of oxygen (O) in compounds is usually -2.
4. The oxidation number of a Group 17 element in a binary compound is -1.
5. The oxidation number of Hydrogen (H) is +1, but it is -1 in when combined with less electronegative elements.
6. The sum of the oxidation numbers of all of the atoms in a neutral compound is zero.
7. The sum of the oxidation numbers in a polyatomic ion is equal to the charge of the ion.
As [tex]Cl_2[/tex] exists as a free molecule, its oxidation state is zero.
Let's say you asked how many moles of O2
are needed to react with 24 moles of C2H6.
Answer:
7
Explanation:
What do you think is responsible for the color produced in the flame, the metal atom or what is attached to the metal atom?
Hint: The metal atom comes first in the formula and the name of the compound.
Answer:
metal Atom
Explanation:
every transition metal atom are responsible for the flame color. Some metal are also confirmed by flame test.
which will dissolve faster in water rock salt or granulated salt
Answer:
Salt!!!
Explanation:
Need help now
Approximate half-life
Radon-222 = 4 days
A sample contains 18mg of radon-222. You estimate that this is 0.01% of the original isotope. How many half-lives have passed?
13 half-lives have passed
Further explanationGeneral formulas used in decay:
[tex]\large{\boxed{\bold{N_t=N_0(\dfrac{1}{2})^{t/t\frac{1}{2} }}}[/tex]
T = duration of decay
t 1/2 = half-life
N₀ = the number of initial radioactive atoms
Nt = the number of radioactive atoms left after decaying during T time
t1/2 = 4 days
Nt=18 mg (0.01% of the original isotope)
18 mg (Nt) = 0.01% No
No = the original isotope :
[tex]\tt No=\dfrac{100}{0.01}\times 18~mg=180,000[/tex]
The duration of decay (T) :
[tex]\tt \dfrac{Nt}{No}=\dfrac{1}{2}^{T/4}\rightarrow Nt=0.01\%No[/tex]
[tex]\tt 0.01\%=\dfrac{1}{2}^{T/4}\\\\10^{-4}=\dfrac{1}{2}^{T/4}\\\\(\dfrac{1}{2})^{13}=\dfrac{1}{2}^{T/4}\\\\13=T/4\rightarrow T=52~days[/tex]
Half-lives passed :
[tex]\tt \dfrac{52}{4}=13~half-lives[/tex]
MCQ
A sample of tungsten occupies a volume of 1.6 cm3. How many atoms of
tungsten in the sample? (For tungsten, density = 19.35 g/cm3)
O 61.92
O 0.337
2.03X10^23
O 1.014X1023
5.07X10^22
O 2.54X10-22
Answer:
1.014×10²³ atoms
Explanation:
Given data:
Volume of tungsten = 1.6 cm³
Density of tungsten = 19.35 g/cm³
Number of atoms of tungsten = ?
Solution:
First of all we will calculate the mass of tungsten.
density = mass/volume
by putting values,
19.35 g/cm³ = mass/1.6 cm³
Mass = 19.35 g/cm³× 1.6 cm³
Mass = 30.96 g
Number of moles of tungsten:
Number of moles = mass/molar mass
Number of moles = 30.96 g/ 183.84 g/mol
Number of moles = 0.1684 mol
1 mole contain 6.022×10²³ atoms.
0.1684 mol × 6.022×10²³ atoms / 1mol
1.014×10²³ atoms
True or False: Radon is a solid at – 100 °C.
How many liters of carbon dioxide are formed from the complete decomposition of 50.0 g of iron (III) carbonate at STP?
Answer:
V = 1.57 L
Explanation:
Given data:
Mass of iron(III) carbonate = 50.0 g
Volume of CO₂ formed = ?
Temperature = standard = 273 K
Pressure = standard = 1 atm
Solution:
Chemical equation:
Fe₂(CO₃)₃ → Fe₂O₃ + 3CO₂
Number of moles of Fe₂(CO₃)₃ :
Number of moles = mass/molar mass
Number of moles = 50.0 g /235.8 g/mol
Number of moles = 0.21 mol
Now we will compare the moles of Fe₂(CO₃)₃ and CO₂.
Fe₂(CO₃)₃ : CO₂
1 : 3
0.21 : 1/3×0.21 = 0.07 mol
Volume of CO₂:
PV = nRT
R = general gas constant = 0.0821 atm.L/mol.K
By putting values,
1 atm × V =0.07 mol × 0.0821 atm.L/mol.K × 273 K
V = 1.57 atm.L / 1 atm
V = 1.57 L
How much of a sample remains after five half-Iives have occurred?
1/5 of the original sarmple
1/25 of the original sarmple
1/32 of the original sample
1/64 of the original sample
Answer:
1/32 of the original sample
Explanation:
edgunity got it.
The mass of magnesium ions in 1 kg of sea water is 1.3 g.
The concentration in parts per million (ppm) is
a 1.3x10^6
b 1.3x10^3
c 1.3x10^-3
I dont understand how to do this question. Help would be much appreciated!
Answer:
1300 ppm
Explanation:
for ppm, calculate fractional ration =(part/total) and multiply by 1 x 10⁶ => ppm
for ppb, calculate fractional ration =(part/total) and multiply by 1 x 10⁹ => ppb
Parts Per Million (ppm)
Given 1.36g in 1Kg (=1000g) => fractional ratio = (1.3g/1000g)(10⁶) = 1300 ppm
Parts Per Billion (ppb)
or if ppb is needed do the same calculation but multiply by 10⁹ ... That is,
Given 1.36g in 1Kg (=1000g) => fractional ratio = (1.3/1000g)(10⁹) = 1300000 ppb = 1.3 x 10⁶ ppb
Parts per Hundred (pph) is the same as percent (%) ... Calculate fractional ratio and then multiply by 100%
Given 1.36g in 1Kg (=1000g) => fractional ratio = (1.3g/1000g)(100%) = 0.13%
QUESTION TWO
(a) Derive Nernst equation for measuring the EMF of the cell
(b) Calculate the emf of the cell
[3]
Zn Zn? (0.001M)|| Agt (0.1M)| Ag
The standard potential of Ag/Ag half-cell is +0.80 V and Zn/Zn. is -0.76 V
(c) Name different types of standard electrodes used for the determination of pH
of a solution by EMF measurement Discuss the working of Glass Electrode
for the determination of pH of a solution
(d) 0.1978 g of copper is deposited by a current of 0.2 ampere in 50 minutes.
What is the electrochemical equivalent of copper?
[3]
Answer:
Screenshot
Explanation:
help me in my this plzzz
Answer:
a is oxidation
b is reduction
c is reduction
d is oxidation
hope it helps you
This is the chemical formula for acetic acid (the chemical that gives the sharp taste to vinegar): An analytical chemist has determined by measurements that there are moles of oxygen in a sample of acetic acid. How many moles of hydrogen are in the sample
Answer:
0.11 mol
Explanation:
This is the chemical formula for acetic acid (the chemical that gives the sharp taste to vinegar): CH₃CO₂H. An analytical chemist has determined by measurements that there are 0.054 moles of oxygen in a sample of acetic acid. How many moles of hydrogen are in the sample?
Step 1: Given data
Formula of acetic acid: CH₃CO₂HMoles of oxygen in the sample of acetic acid: 0.054 molesStep 2: Establish the appropriate molar ratio
According to the chemical formula of acetic acid, the molar ratio of H to O is 4:2.
Step 3: Calculate the moles of atoms of hydrogen
We will use the theoretical molar ratio for acetic acid.
0.054 mol O × (4 mol H/2 mol O) = 0.11 mol H
Where are all metalloid found in this periodic table?
Answer:
Explanation:
THe GrEen OnEs
Answer:
They are in the green "staircase"
Explanation:
these elements are the dividers between metals (on the left of them) and non metals (on the right of them), they have some of the properties of both groups
What is the free energy change if the ratio of the concentrations of the products to the concentrations of the reactants is 22.3, and the temperature is 37.0 °C? ?G°\' for the reaction is –16.7 kJ/mol.
The free energy change(Gibbs free energy-ΔG)=-8.698 kJ/mol
Further explanationGiven
Ratio of the concentrations of the products to the concentrations of the reactants is 22.3
Temperature = 37 C = 310 K
ΔG°=-16.7 kJ/mol
Required
the free energy change
Solution
Ratio of the concentration : equilbrium constant = K = 22.3
We can use Gibbs free energy :
ΔG = ΔG°+ RT ln K
R=8.314 .10⁻³ kJ/mol K
[tex]\tt \Delta G=-16.7~kJ/mol+8.314.10^{-3}\times 310\times ln~22.3\\\\\Delta G=-8.698~kJ/mol[/tex]
What is the mass in grams of 12.9 moles of water, H2O?
Answer:
232 g.
Explanation:
12.9 mol x 18.106g = 232 g H₂O
PLEASEEEEEEEEEEEE HELP 100 POINTS PLEASEEEE Sofia has two 10-gram samples of sea salt. One sample is finely ground into thousands of tiny grains of salt. The other sample is a single block of salt crystals. Sofia tries to dissolve each sample in a separate glass of water. Which sample will dissolve first?
A.the finely ground sample because it has more surface area
B.the single block because it has more surface area
C.the single block because it has less surface area
D.the finely ground sample because it has less surface area
Answer:
the answer is D to this question
The capability of a gaseous, solid or liquid component to dissolve in the solvent to yield a solution is called solubility. Solubility depends on the exterior area of the substance.
The correct answer is:
Option A. The finely ground sample because it has more surface area.
This can be explained as:
The rate of desolvation of the solute is dependent on the surface area of the solute.The grounded particle of a substance dissolves faster as compared to the large particles.The solubility of solute depends on the surface area. The large surface area of compounds increases the contact rate of solute with the solvent.Therefore, the finely ground sample will dissolve fast.
To learn more about solubility and surface area follow the link:
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why we add PH10 When we determine the zn ion
Answer:
to make it basic from acidic
What kind of solution would you have if it contained 50 grams of sodium chloride in 100 mL of water at 30˚C?
Answer:
Supersaturated solution.
Explanation:
Hello!
In this case, according to the types of solution in terms of the relative amounts of solute and solvent, we can define a point called solubility at which the amount of solute is no longer dissolved in the solvent; thus, a value of solute/solvent less than the solubility is related to unsaturated solutions, equal to the solubility is related to the saturated solutions and more than the solubility to supersaturated solutions.
Thus, since solubility is temperature-dependent, at 30 °C the solubility of sodium chloride is 36.09 g per 100 mL of water; which means that, since the solution has 50 g of sodium chloride, more than 36.09 g, we infer this is a supersaturated solution.
Best regards!
what are the functional groups in tramadol
Answer:
1. ether group R-O-R
2. benzene ring
3. 3°- alcohol
4.3°- amine group N attached to 3 groups rather than H
How many moles are in
.77 liters of Br2 at STP?
Answer: 0.034354
Explanation:1 mole=22.4 liters of Br2 at STP so, 22.4x=0.77
x= 0.034354
Answer:
0.034354
Explanation:
Just did worksheet
help I. have until 11:59 to hand it in
This chemical reaction can also be written as
2C2H6+7O2-->4CO2+6H2O
This is a chemical reaction because reactants are converted into products. This is the combustion of ethane where ethane and oxygen have been converted into carbon dioxide and water
Which of the following provides evidence for past tectonic plate motions?
A. Matching rock type and rock formations can show the way the continents were once attached.
B.Glacial evidence has been found in areas where glaciers could not exist if the continents were in their current location.
C.Ancient life forms preserved as fossils can tell us what organisms existed and where they were. Matching the fossils can show that land masses were once connected.
D. All of the above.
Answer:
D
Explanation:
If there are 2 of the same rocks on two continents, that shows that they were once merged. If there is glacial existence in places where glaciers would’ve melted (Like Africa has glacial existence from Antarctica ) this shows that continents were once merged. If life forms preserved as fossils were matched on 2 different continents this shows that all the continents were once merged.
Answer:
so i am doing this and i need help what did u get for number 1
Explanation:
its the first question
1) When 2.38g of magnesium is added to 25.0cm of 2.27 M hydrochloric acid, hydrogen gas is released.
a) Determine the limiting reactant
b) Calculate the mass of hydrogen gas produced.
c) Calculate the mass of excess reactant remained at the end of reaction.
d) What is the percentage yield if 0.044g of hydrogen gas is obtained from the experiment?
Answer:
a. HCl.
b. 0.057 g.
c. 1.69 g.
d. 77 %.
Explanation:
Hello!
In this case, since the reaction between magnesium and hydrochloric acid is:
[tex]Mg+2HCl\rightarrow MgCl_2+H_2[/tex]
Whereas there is 1:2 mole ratio between them.
a) Here, we can identify the limiting reactant as that yielded the fewest moles of hydrogen gas product via the 1:1 and 2:1 mole ratios:
[tex]n_{H_2}^{by\ HCl}=0.025L*2.27\frac{molHCl}{1L}*\frac{1molH_2}{2molHCl} =0.0284molH_2\\\\n_{H_2}^{by\ Mg}=2.38gMg*\frac{1molMg}{24.3gMg}*\frac{1molH_2}{1molMg}=0.0979molH_2[/tex]
Thus, since hydrochloric yields fewer moles of hydrogen than magnesium, we realize it is the limiting reactant.
b) Here, we use the molar mass of gaseous hydrogen (2.02 g/mol) to compute the mass:
[tex]m_{H_2}=0.0284molH_2*\frac{2.02gH_2}{1molH_2}=0.057gH_2[/tex]
c) Here, we compute the mass of magnesium associated with the yielded 0.0248 moles of hydrogen:
[tex]m_{Mg}^{reacted}=0.0284molH_2*\frac{1molMg}{1molH_2}*\frac{24.3gMg}{1molMg} =0.690gMg[/tex]
Thus, the mass of excess magnesium turns out:
[tex]m_{Mg}^{excess}=2.38g-0.690g=1.69gMg[/tex]
d) Finally, we compute the percent yield, considering 0.044 g is the actual yield and 0.057 g the theoretical yield:
[tex]Y=\frac{0.044g}{0.057g} *100\%\\\\Y=77\%[/tex]
Best regards!
a) The limiting reactant would be HCl
From the equation of the reaction:
[tex]Mg (s) + 2 HCl (aq) ---> MgCl_2 (aq) + H_2 (g)[/tex]
The mole ratio of Mg to HCl is 1:2.
Mole = mass/molar mass = molarity x volume
Mole of Mg = 2.38/24.3
= 0.098 moles
Mole of HCl = 2.27 x 25/1000
= 0.057 moles
Thus, HCl is limiting while Mg is in excess.
b) Since the mole ratio of HCl to H2 is 2:1:
Mole of H2 produced = 0.057/2
= 0.028 moles
Mass of H2 produced = mole x molar mass
= 0.028 x 2
= 0.057 g
c) Actual mole of Mg that should react = 0.057/2
= 0.028 moles
Excess mole of Mg = 0.098 - 0.028
= 0.07
Mass of excess Mg = 0.07 x 24.3
= 1.701 g
d) Percentage yield if 0.044 g of hydrogen is obtained = yield/theoretical x 100
= 0.044/0.057 x 100
= 77.19%
Please help me I really need this done
Answer is 2
4Fe + 3O2 –> 2Fe2O3
Question 10 of 25
Consider this reaction:
Mg(s) + 2H2O(1) ► Mg(OH)2(s) + H2(g)
What is the oxidation state of Mg in Mg(OH)2(s)?
A. +2
B. - 2
C. +1
D. 0
The oxidation number of Mg in Mg(OH)₂ is +2.
Hence, Option A is correct answer.
What is oxidation number?The oxidation state, or oxidation number, is defined as the hypothetical charge of an atom if all of its bonds formed with different atoms were fully ionic. It indicates the degree of oxidation of an atom in a chemical compound. Conceptually, the oxidation state may be negative, positive or zero.
Oxidation number of OH = -1
Let us suppose the oxidation number of Mg = x
Charge on compound = 0
We can write
x + 2(-1) =0
x-2=0
x = 2
Thus from the above solution we concluded that The oxidation number of Mg is +2.
Hence, Option A is correct answer.
Learn more about oxidation number:
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