Answer:
0.3125 g
Explanation:
Given data:
Half life of barium-122 = 2 min
Mass of sample = 10.0 g
Mass of barium remain after 10 min = ?
Solution:
Number of half lives = Time elapsed / half life
Number of half lives = 10 min/ 2 min
Number of half lives = 5
At time zero = 10 g
At 1st half life = 10 g/2 = 5 g
At 2nd half life = 5 g/2 = 2.5 g
At 3rd half life = 2.5 g/2 = 1.25 g
At 4th half life = 1.25 g/2 = 0.625 g
At 5th half life = 0.625 g/2 = 0.3125 g
How many moles of precipitate will be formed when 100.0 mL of 0.200 M NaBr is reacted with excess Pb(NO₃)₂ in the following chemical reaction?
2 NaBr (aq) + Pb(NO₃)₂ (aq) → PbBr₂ (s) + 2 NaNO₃ (aq)
Answer : The number of moles of precipitate, [tex]PbBr_2[/tex] formed will be 0.01 moles.
Explanation : Given,
Concentration of NaBr = 0.200 M
Volume of solution = 100.0 mL = 0.1 L (1 L = 1000 mL)
First we have to calculate the moles of NaBr.
[tex]\text{Moles of NaBr}=\text{Concentration of NaBr}\times \text{Volume of solution in L}[/tex]
[tex]\text{Moles of NaBr}=0.200M\times 0.1L=0.02mol[/tex]
Now we have to calculate the moles of precipitate, [tex]PbBr_2[/tex] formed.
The balanced chemical reaction is:
[tex]2NaBr(aq)+Pb(NO_3)_2(aq)\rightarrow PbBr_2(s)+2NaNO_3(aq)[/tex]
From the balanced chemical reaction we conclude that:
As, 2 moles of NaBr react to give 1 mole of [tex]PbBr_2[/tex]
So, 0.02 moles of NaBr react to give [tex]\frac{0.02}{2}=0.01[/tex] mole of [tex]PbBr_2[/tex]
Therefore, the number of moles of precipitate, [tex]PbBr_2[/tex] formed will be 0.01 moles.
The number of mole of the precipitate (i.e PbBr₂) formed when 100 mL of 0.2 M NaBr react with excess Pb(NO₃)₂ is 0.01 mole
We'll begin by calculating the number of mole of NaBr in 100 mL of 0.2 M NaBr solution. This can be obtained as follow:Volume = 100 mL = 100 / 1000 = 0.1 L
Molarity of NaBr = 0.2 M
Mole of NaBr =?Mole = Molarity x Volume
Mole of NaBr = 0.2 × 0.1
Mole of NaBr = 0.02 mole Finally, we shall determine the number of mole of the precipitate (i.e PbBr₂) produced from the reaction. This can be obtained as follow:2NaBr(aq) + Pb(NO₃)₂(aq) → PbBr₂(s) + 2NaNO₃ (aq)
From the balanced equation above,
2 moles of NaBr reacted to produce 1 mole of PbBr₂.
Therefore,
0.02 mole of NaBr will react to produce = [tex]\frac{0.02}{2} \\\\[/tex] = 0.01 mole of PbBr₂.
Thus, the number of mole of the precipitate (i.e PbBr₂) produced from the reaction is 0.01 mole
Learn more: https://brainly.com/question/19572703
using this chemical might discolour equipment and surfaces
Answer: do not know how to answer this
Explanation:
Y-Chart
Explain how an invasive species can influence each aspect of an ecosystem.
Answer:
Invasive species are an organism that causes ecological or economic harm in a new environment where it's not native.
Explanation:
An invasive species can harm both the natural resources in the ecosystem as well it threaten the human use of these resources and invasive species can be introduced to a new area via the ballast water of oceangoing ships, intentional and accidental releases of aquaculture species, aquarium specimens or bait, and etc.
Invasive species is capable of causing extinctions to native plants and animals, reducing biodiversity, competing with native organisms for limited resources, and altering habitats. This can also result a huge economic impacts and fundamental disruptions of coastal and the great lakes of the ecosystems.
I hope it helps you.
Which element is classified as a noble gas?
Answer:
The elements with completely filled shells are classified as noble gases
That is why we only see noble gases on the rightmost corner of the periodic table, it is because they have the maximum number of electrons in a shell
Examples of noble gases
Helium , Neon , Argon and Krypton are some examples of noble gases
Answer:
D. (Xe) XenonExplanation:
I JUST TOOK THE TEST!
A student reacts 5.0 g of sodium with 10.0 g of chlorine and collect 5.24 g of sodium chloride. What is the percent yield of this combination reaction
Answer: The percent yield of this combination reaction is 41.3 %
Explanation : Given,
Mass of [tex]Na[/tex] = 5.0 g
Mass of [tex]Cl_2[/tex] = 10.0 g
Molar mass of [tex]Na[/tex] = 23 g/mol
Molar mass of [tex]Cl_2[/tex] = 71 g/mol
First we have to calculate the moles of [tex]Na[/tex] and [tex]Cl_2[/tex].
[tex]\text{Moles of }Na=\frac{\text{Given mass }Na}{\text{Molar mass }Na}[/tex]
[tex]\text{Moles of }Na=\frac{5.0g}{23g/mol}=0.217mol[/tex]
and,
[tex]\text{Moles of }Cl_2=\frac{\text{Given mass }Cl_2}{\text{Molar mass }Cl_2}[/tex]
[tex]\text{Moles of }Cl_2=\frac{10.0g}{71g/mol}=0.141mol[/tex]
Now we have to calculate the limiting and excess reagent.
The balanced chemical equation will be:
[tex]2Na+Cl_2\rightarrow 2NaCl[/tex]
From the balanced reaction we conclude that
As, 2 mole of [tex]Na[/tex] react with 1 mole of [tex]Cl_2[/tex]
So, 0.217 moles of [tex]Na[/tex] react with [tex]\frac{0.217}{2}=0.108[/tex] moles of [tex]Cl_2[/tex]
From this we conclude that, [tex]Cl_2[/tex] is an excess reagent because the given moles are greater than the required moles and [tex]Na[/tex] is a limiting reagent and it limits the formation of product.
Now we have to calculate the moles of [tex]NaCl[/tex]
From the reaction, we conclude that
As, 2 mole of [tex]Na[/tex] react to give 2 mole of [tex]NaCl[/tex]
So, 0.217 mole of [tex]HCl[/tex] react to give 0.217 mole of [tex]NaCl[/tex]
Now we have to calculate the mass of [tex]NaCl[/tex]
[tex]\text{ Mass of }NaCl=\text{ Moles of }NaCl\times \text{ Molar mass of }NaCl[/tex]
Molar mass of [tex]NaCl[/tex] = 58.5 g/mole
[tex]\text{ Mass of }NaCl=(0.217moles)\times (58.5g/mole)=12.7g[/tex]
Now we have to calculate the percent yield of this reaction.
Percent yield = [tex]\frac{\text{Actual yield}}{\text{Theoretical yield}}\times 100[/tex]
Actual yield = 5.24 g
Theoretical yield = 12.7 g
Percent yield = [tex]\frac{5.24g}{12.7g}\times 100[/tex]
Percent yield = 41.3 %
Therefore, the percent yield of this combination reaction is 41.3 %
How many elements are in calcium dihydrogren phosphate
What was the atomic theory about?
A. The properties of the nucleus
B. The existence of isotopes
C. The structure of the atom
D. The existence of electrons
Answer:
The structure of the atom
Please help me!!!:)))
Answer:
blocks 1 and 2 the rhdh huff hgfhh5
1. Marisa determined the melting point of a substance to be 24.5C. Find the percent error of her measurement if the actual melting point is 31.2C.
Answer:
[tex]\%\ Error = 21.5\%[/tex]
Explanation:
Given
[tex]Measured = 24.5[/tex]
[tex]Actual = 31.2[/tex]
Required
Determine the percentage error
First, we need to determine the difference in the measurement
[tex]Difference = |Actual - Measured|[/tex]
[tex]Difference = |31.2 - 24.5|[/tex]
[tex]Difference = |6.7|[/tex]
[tex]Difference = 6.7[/tex]
The percentage error is calculated as thus:
[tex]\%\ Error = \frac{Difference * 100\%}{Actual}[/tex]
[tex]\%\ Error = \frac{6.7 * 100\%}{31.2}[/tex]
[tex]\%\ Error = \frac{670\%}{31.2}[/tex]
[tex]\%\ Error = 21.4743589744\%[/tex]
[tex]\%\ Error = 21.5\%[/tex] approximated
8. Why is the magnetic force considered to be a noncontact force?
Answer:
Magnetic forces are non contact forces; they pull or push on objects without touching them. Magnets are only attracted to a few 'magnetic' metals and not all matter. Magnets are attracted to and repel other magnets.
Hope this helps!!!
Explanation:
Hereditary information is passed on from:
O nucleus to nucleus
O cell to cell
O cell to nucleus
O nucleus to cell
Answer:
D - Nucleus to Cell
Explanation:
Hope it helps!!
:D
‘ASAP’What do the different categories of hurricanes represent?
O Air density
O Humidity
O Pressure
O Wind speeds
Answer:
Sorry I do not know the answer but I do know its not c (pressure)
Explanation:
I took a quiz with that question and I got it wrong my other guess is air density though
Answer:
Wind Speeds
Explanation:
im awnsering late cuz i need pointsss
What does a dissolved salt look like?
Answer:(trick question) once the salt has dissolve in the water it is no longer visible
Thank you! have an amazing day.
I don't know what category to put this question in, but I attached a photo of it. Can someone please help me answer it?
Analysing the question:
To calculate the density of a material, we need its mass and volume
We are given:
Mass of sample = 21 grams
dimensions of the sample = 1 * 1 * 2 = 2 cm³
Calculating the density:
Density = Mass of sample / volume of sample
Replacing the variables
Density = 21 / 2
Density = 10.5 g / cm³
Determining the Material:
From the table provided, we can see that the density of Silver is 10.5 g/cm³
Therefore, the material is Silver
Determine the volume of 15.5 g of a substance with a density of 6.89 g/ml
Answer:
The answer is 2.25 mLExplanation:
The volume of a substance when given the density and mass can be found by using the formula
[tex]volume = \frac{mass}{density} \\ [/tex]
From the question
mass = 15.5 g
density = 6.89 g/mL
We have
[tex]volume = \frac{15.5}{6.89} \\ = 2.249637155...[/tex]
We have the final answer as
2.25 mLHope this helps you
i’m so lost please help
C=4
D=-19
Explanation:
2exp-25/5exp-7= 4exp-19
True or False: All cells have different basic chemical composition. *
True
False
When 435 J of heat is added to 3.4 g of olive oil that's at 21 Deg C, it's
temperature increases to 85 Deg C. Calculate the specific heat of Olive oil? Show work
Answer:
k Nishant
Explanation:
i don't know sorry but u can search in google
What can you infer about the likely occurrence of the other isotopes in each of the
above elements? Explain your reasoning.
Answer:
Most common has the same or closest mass because it is closer to the original’s mass.
Explanation:
I got it from the answer key
Read more here:
https://brainly.com/question/1598931
What is the density of a block of gold that occupies 1000 ml and has a mass of 3.5 kg? Show your work
Answer:
We are given:
mass of the block = 3500 grams
volume of the block = 1000 mL
Finding the density:
Density = mass of the object (in grams) / volume of the object (in mL)
Density = 3500 / 1000
Density = 3.5 g / mL
HELP PLEASE, IM ON A TIMER ⏱
Which describes an attribute of nonrenewable resources?
A.) exist in fixed amounts
B.) are unlimited
C.) can often be replaced in a short time
D.) are replaced faster than they are used
Answer:
A. exist in fixed amounts or available in limited supplies
Explanation:
Answer:
A
Explanation:
If equal volumes of a strong base and a weaker acid are mixed together, what would you expect the pH of the resulting salt to be
Answer:
Above 7
Explanation:
The equivalence point of any titration can be read off from the appropriate titration curve.
A titration curve is a plot of the pH of analyte against the volume of titrant added.
For a strong base and weak acid, the equivalence point lies above 7.
The pH of the resulting salt to be pH> 7 .
What does Equivalence point tell?The equivalence point of any titration can be read off from the appropriate titration curve. A titration curve is a plot of the pH of analyte against the volume of titrant added. It is a point in titration at which the amount of titrant added is just enough to completely neutralize the analyte solution. At the equivalence point in an acid-base titration.
For a strong base and weak acid, the equivalence point lies above 7.
Find more information about Equivalence point here:
brainly.com/question/18933025
__________ 5. Chemical equilibrium is the result of A. all of the reactants being converted into products. B. stoppage of further reaction. C. formation of products equal in mass to the mass of the reactants. D. opposing reactions attaining equal rates. E. a loss of pressure in the system.
Answer:
The correct option is C
Explanation:
Chemical equilibrium is a state in which there is no net change in the amount of reactant and products formed over time. This reaction is a reversible reaction, hence the reaction can keep proceeding in either direction until the products formed are equal in mass to that of the reactants or the products been reversed back to the reactants until both sides (product and reactant) achieve equal mass.
The initial pressure of a mixture of C6H6 and an excess of H2 in a rigid vessel is 1.21 atm. A catalyst is introduced. After the reaction reaches completion, the temperature is restored to its initial value. The final pressure in the vessel is 0.839 atm. What was the mole fraction of C6H6 in the original mixture
Answer:
mole fraction of C6H6 = 0.613 atm
Explanation:
The equation for this reaction is :
[tex]C_6H_6 _{(g)} + 3H_2_{(g)} \to C_6H_{12}_{(g)}[/tex]
Initial P₁ P₂ 0
Final 0 P₂ -P₁/2 P₁
After completion of the reaction;
P₁ + P₂ = 1.21 atm ----- (1)
P₂ - P₁/2 + P₁ = 0.839 atm
P₂ + P₁/2 = 0.839 atm ----- (2)
Subtracting (2) from (1); we have:
P₁/2 = 0.371
P₁ = 0.742 atm
From(1)
P₁ + P₂ = 1.21 atm
0.742 atm + P₂ = 1.21 atm
P₂ = 1.21 atm - 0.742 atm
P₂ = 0.468 atm
Thus, the partial pressure of C6H6 = 0.742 atm
∴
Partial pressure = Total pressure × mole fraction of C6H6
mole fraction of C6H6 = Partial pressure / Total pressure
mole fraction of C6H6 = 0.742 atm / 1.21 atm
mole fraction of C6H6 = 0.613 atm
__________ have the lowest ionization energies of the groups listed
PLZ HELP I'LL AWARD BRAINLIEST
Answer: have the lowest ionization energies of the groups listed
PLZ HELP I'LL AWARD BRAINLIEST
Explanation:
Determine the molar mass of CaO
Express the following numbers in scientific notation:
872
Answer:
The number 872 would be written as,
8.72× 10²
Explanation:
Scientific notation is used to express the large value in short form.
The number in scientific notation have two parts.
First part:
The digits (decimal point will place after first digit)
Second part:
× 10 ( the power which put the decimal point where it should be)
For example the number 872 would be written as
8.72× 10²
Another example:
6324.4 in scientific notation will be written as = 6.3244 × 10³
PLEASE HELP AND FAST!!!
Cementation is part of the process of
A. igneous intrusion
B. lithification
C. igneous extrusion
D. metamorphism
SUBMIT
Answer:
The correct answer is b.
Explanation:
hope this helps u
Answer:
Bryna is correct it is B
Explanation:
How many grams of NO2 would be formed from 1.0 mole of NO and excess of O2?
Answer:
Mass = 46 g
Explanation:
Given data:
Number of moles of NO = 1.0 mol
Amount of O₂ = excess
Mass of NO₂ formed = ?
Solution:
Chemical equation:
2NO + O₂ → 2NO₂
Now we will compare the moles of No with NO₂.
NO : NO₂
2 : 2
1 : 1
Mass of NO₂ in gram:
Mass = number of moles × molar mass
Mass = 1 mol ×46 g/mol
Mass = 46 g