Answer:
15.32 days
Explanation:
From the question given above, the following data were obtained:
Half-life (t½) = 3.83 days
Original amount (N₀) = 225 g
Amount remaining (N) = 14.06 g
Time (t) =.?
Next, we shall determine the number of half-lives that has elapsed. This can be obtained as follow:
Original amount (N₀) = 225 g
Amount remaining (N) = 14.06 g
Number of half-lives (n) =?
N = N₀ / 2ⁿ
14.06 = 225 / 2ⁿ
Cross multiply
14.06 × 2ⁿ = 225
Divide both side by 14.06
2ⁿ = 225 / 14.06
2ⁿ = 16
Express 16 in index form with 2 as the base
2ⁿ = 2⁴
n = 4
Thus, 4 half-lives has elapsed.
Finally, we shall determine the time. This can be obtained as follow:
Half-life (t½) = 3.83 days
Number of half-lives (n) = 4
Time (t) =.?
n = t / t½
4 = t / 3.83
Cross multiply
t = 4 × 3.83
t = 15.32 days
Therefore the time for 225 g sample of Radon to decay to 14.06 g is 15.32 days
how a scientist might use a graph of the
relationship between population growth and time to identify
a trend
hellppppppp asap please NO FILES
Answer:
Q1: c. 7.2 g.
Q2: a. 0.42 M.
Explanation:
Hello there!
In this case, according to the definition of molarity as moles of solute divided by volume of solution in liters, we can proceed as follows:
Q1: Here, given the molarity and volume we can calculate the moles of the sugar as follows:
[tex]n=M*V=0.4mol/L*0.1L\\\\n=0.04 mol[/tex]
Next, since its molar mass is about 180 g/mol, the mass turns out:
[tex]0.04mol*\frac{180g}{1mol} =7.2 g[/tex]
Therefore, the answer is c. 7.2 g.
Q2: Here, recalling the definition of molarity, we can just plug in the 0.629 moles and 1.500 L to obtain:
[tex]M=\frac{0.629mol}{1.5L}\\\\M=0.42M[/tex]
Therefore, the answer is a. 0.42 M.
Best regards!
If you have 7 moles of water, how many atoms do you have?
Answer:
Explanation:
Given 7 moles H₂O
By definition, the 'mole', in chemical process, is the mass of substance (usually in grams and includes elements or molecules) that contain 6.023 x 10²³ particles (Avogadro's Number) of the given substance. The mole is also related (or, equal) to the following:
1 mole = 1 Avogadro's number of particles = 6.023 x 10²³ particles = 1 formula wt. = 1 molecular wt. = 1 gram formula weight
So, if given 7 moles of water (H₂O) => ? molecules of water (H₂O)
By the Avogadro relationship => 1 mole H₂O = 6.023 x 10²³ molecules of H₂O
Then 7 moles H₂O => 7 moles x 6.023 x 10²³ molecules H₂O/mole H₂O
= 4.216 x 10²⁴ water molecules.
_________________________________-
General FYI note ... if needed ...
The subscripts identify number of moles of element in one mole of formula weight. That is while 1 mole H₂O contains 6.023 x 10²³ molecules of water it also contains 2 moles of hydrogen or, 2 x 6.02 x 10²³ atoms of hydrogen and moles of oxygen 1 x 6.023 x 10²³ atoms of oxygen.
What factors – physical, historical, and otherwise – have contributed to the traditional identification of multiple “oceans” versus the concept of a single, global ocean?
Answer:
According to this theory, the ocean formed from the escape of water vapor and other gases from the molten rocks of the Earth to the atmosphere surrounding the cooling planet. After the Earth's surface had cooled to a temperature below the boiling point of water, rain began to fall—and continued to fall for centuries.
Explanation:
state the type of enthalpy in the followinv equation Koh+Hcl-kcl+h2o ∆h+=-57kj\mol
Answer:
The Enthalpy of neutralization
Explanation:
The reaction of a base (KOH) with an acid (HCl) produce water and its salt (KCl) is called Neutralization Reaction.
This neutralization releases 57kJ/mol.
As the type of enthalpy is due the type of reaction. This enthalpy is:
The Enthalpy of neutralizationWhat is the molarity of a solution that contains 224 grams of KOH in 2
liters of solution?
Answer:
[tex]\boxed {\boxed {\sf 2 \ M \ KOH}}[/tex]
Explanation:
Molarity is a measure of concentration in moles per liter.
1. Grams to MolesThe first step is to convert the amount of grams given to moles. The molar mass is used. This found on the Periodic Table and it's the same value as the atomic mass, but the units are grams per mole.
We have 224 grams of KOH. Look up the molar masses for the individual elements.
Potassium (K): 39.098 g/mol Oxygen (O): 15.999 g/mol Hydrogen (H): 1.008 g/molSince the compound's formula has no subscripts, 1 formula unit has 1 atom of each element. We can simply add the molar masses together to find KOH's molar mass.
KOH: 39.098 + 15.999 + 1.008=56.105 g/molUse this number as a ratio.
[tex]\frac {56.105 \ g\ KOH}{1 \ mol \ KOH}[/tex]
Multiply by the value we are converting: 224 g KOH
[tex]224 \ g \ KOH *\frac {56.105 \ g\ KOH}{1 \ mol \ KOH}[/tex]
Flip the ratio so the units of grams KOH cancel.
[tex]224 \ g \ KOH *\frac {1 \ mol \ KOH}{56.105 \ g\ KOH}[/tex]
[tex]224 *\frac {1 \ mol \ KOH}{56.105}[/tex]
[tex]\frac {224}{56.105} \ mol \ KOH[/tex]
[tex]3.992514036 \ mol \ KOH[/tex]
2. Calculate MolarityRemember molarity is moles per liter.
[tex]molarity = \frac{moles}{liters}[/tex]
We just calculated the moles and we know there are 2 liters of solution.
[tex]molarity = \frac{ 3.992514036 \ mol \ KOH}{ 2 \ L}[/tex]
[tex]molarity= 1.996257018 \ mol \ KOH/ L[/tex]
3. Round and Convert UnitsFirst, let's round. The original values have 3 and 1 significant figures. We go with the lowest number: 1. For the number we found, that is the ones place.
1.996257018The 9 in the tenths place tells us to round to 1 up to a 2
[tex]2 \ mol \ KOH/ L[/tex]
Next, convert units. 1 mole per liter is equal to 1 molar or M.
[tex]2 \ M \ KOH[/tex]
The molarity of the solution is 2 M KOH
Answer:
2M of KOH
Explanation:
224 g of KOH in 2 liters of KOH
? of KOH in 1 liters of KOH
[tex]\frac{224}{2} = 112g of KOH[/tex]
1 mole of KOH = 39 + 16+ 1 = 56g
?mole of KOH = 112g
[tex]\frac{112}{56}[/tex]moles of KOH = 2 moles/1liter of KOH
written as 2M KOH
electron configuration assignment pleaseee help asappp its 100 points and I give out brainly <3
Answer:
https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Quantum_Mechanics/10%3A_Multi-electron_Atoms/Electron_Configuration
Explanation:
When determining the amount of an oxidant present by titration, you can use iodine and starch as an indicator.
First, the oxidant, like hypochlorite, oxidizes
Choose...
neutral iodine into iodide ion
iodide ion into neutral iodine
iodate polyatomic ion into iodide ion
When starch and iodine are both present, the solution is
Choose...
blue-black
brownish yellow
clear
During the titration, the titrant, like thiosulfate, reduces the
Choose...
iodide ion into iodate polyatomic ion
neutral iodine into iodide ion
iodide ion into neutral iodine
When the iodine has completely reacted at the endpoint of the titration, the solution should become
Choose...
clear
blue-black
brownish yellow
Answer:
1. iodide ion into neutral iodine
2. blue-black
3. neutral iodine into iodide ion
4. clear
Explanation:
The function of hypochlorite in iodine titration is to oxidize the iodide ion into iodine molecule as shown below;
ClO-(aq) + 2H+(aq) + 2I-(aq) ---------> 6 I2(l) + Cl- (aq)+ H2O(l)
The addition of starch to iodine leads to the formation of a starch iodide complex which has a blue black colour.
the titrant, thiosulfate, reduces neutral iodine into iodide ion as shown below;
I2 + 2S2O32- → 2I- + S4O62-
At end point, the solution becomes clear again.
What volume will 28 grams of nitrogen gas occupy at 27 Celsius and a
pressure of 785 mm Hg?
Answer: [tex]2.49\ m^3[/tex]
Explanation:
Given
Mass of nitrogen present [tex]m=28\ g[/tex]
Temperature [tex]T=27^{\circ}C\equiv 300\ K[/tex]
Pressure [tex]P=785\ mm\ \text{of}\ Hg\ \text{or}\ 1.032\ atm[/tex]
The molar mass of Nitrogen [tex]M=28\ g/mol[/tex]
No of moles of nitrogen present
[tex]n=\dfrac{m}{M}\\\\n=\dfrac{28}{28}\\\\n=1[/tex]
Using [tex]PV=nRT[/tex]
[tex]\Rightarrow 1.032\times V=1\times 8.314\times 300\\\\\Rightarrow V=\dfrac{2494.2}{1.032}\\\\\Rightarrow V=2494.2\ L\ \text{or}\ 2.49\ m^3[/tex]
My swimming pool is rectangular (16 feet by 34 feet) and has a depth of 6 feet. Lets imagine that my pool water is full to the top and is heated by a laser that emits photons with a wavelength of 520 nm. The starting temperature of my pool is a chilly 52 degrees Celsius. How many moles of photons would be required to heat the pool to a balmy 80 degrees Celsius
Answer:
Number of moles of photons required = 5.04 × 10⁴ moles
Explanation:
The energy of a photon can be calculated from Planck's equation E = hc/λ
Where h = 6.63 × 10-³⁴ Js and c, the velocity of light = 3.0 × 10⁸ m/s
Energy of one mole of photons = N₀ × hc/λ
wavelength of photon, λ = 520 nm = 5.20 × 10-⁷ m
Energy of one mole of photons = 6.02 × 10²³ × 6.63 × 10−³⁴ × 3 × 10⁸/5.20 × 10-⁷
Energy of one mole of photons = 2.30 × 10⁵ J/mol
Energy required to raise the temperature of a given mass of a substance, E = mcΔT
Where m is mass of substance, c is specific heat capacity, ΔT is temperature difference
Mass ofnwternin the pool = volume × density
Volume of water = Volume of swimming pool
Volume of water = 16 × 34 × 6 ft³ = 3264 ft³
1 ft³ = 28316.8 cm³; 3264 ft³ = 28316.8 × 3264 = 92426035.2 cm³
Density of water = 1 g/cm³
Mass of water = 92426035.2 cm³ × 1 g/cm³ = 92426035.2g
ΔT = 80°C - 50°C = 30°C, c = 4.18 J/g/K
Energy required to raise 92426035.2 g water by 30° C = 92426035.2 × 4.18 × 30
Energy required = 1.16 × 10¹⁰ J
Hence, number of moles of photons required = 1.16 × 10¹⁰ J/2.30 × 10⁵ J/mol
Number of moles of photons required = 5.04 × 10⁴ moles
1. A bird perching in the tree hears the chirping of another bird. A whale hears
the songlike sound made by another whale swimming pcar it. Which sound
travels faster, the bird's chirping or the whale's singing? Explain your answer.
Answer:
The sound from the whales singing is faster than that from the birds chirping.
Explanation:
The sound from the whales singing will travel faster than the sound from the birds chirping because sound travels faster through a medium than through air.
In this case the whales are in water which is a medium while the birds are in the air and thus, the sound from the water will travel faster.
in the cell, newely made proteins move directly from the ribosomes into the rough _____ _____, where they are chemically modified
Answer:
endoplasmic reticulum
Explanation:
there it is
3.2 g of a gas at STP occupies a volume of 2.24 L. The gas is
Answer:
Oxygen
Explanation:
What are the things that is solid?
A. water
B. rock
C. oil
D. module
Answer:
The answers for these questions are B. rock and D. Module because they are both solids. The other two water and oil are liquids.
Give the name of the products formed
between Benzene and the following Compounds
Br2,Cl2,HNO3,H2SO4,HCOCl
1-chlore-2,2-dimethylpropane
Answer:
With Br2 - Bromobenzene
With Cl2 - Chlorobenzene
With HNO3- Nitrobenzene
With H2SO4 - Benzenesulphonic acid
With HCOCl - Benzoyl chloride
With 1-chloro-2,2-dimethylpropane - 2,2dimethyl-1-phenyl propane
Explanation:
The common thread joining all these reactions is that they are all electrophillic reactions. They are so called because the attacking agents in each reagent is an electrophile. Electrophiles are species that have electron deficient centers and are known to attack molecules that are high in electron density at regions of high electron density.
The benzene molecule has rich electron density. Any substituents that donates electrons to the ring improves the likelihood that benzene will undergo electrophillic substitution reactions while electron withdrawing substituents decrease the likelihood that benzene will undergo electrophillic substitution reactions.
The names of the compounds formed when benzene undergoes electrophillic reaction with the attacking agents listed in the question are displayed in the answer section.
sdfsdfsdfsfsdfsdfdfdre
Answer:
310 mmHg
Explanation:
All you have to do here in order to figure out the pressure exerted by gas
D is use Dalton's Law of Partial Pressures.
If anyone has done the edge acids and bases lab please help me it would be deeply appreciated
Answer:
Do you mean a biology lab
Explanation:
what's the question
Select the TRUE statements below regarding the coordination compound prepared in lab. Group of answer choices The coordination compound contained a complex ion that was covalently bonded to sulfate. The ligand must have at least one unshared pair of valence electrons in order to covalently bond with transition metal in the coordination compound. Ethanol was used during crystallization of the coordination compound because the compound is soluble in ethanol. The ammonia is covalently bonded to the transition metal. The colors of many coordination compounds are the result of light absorption by the d electrons on the transition metal.
Answer: Hello the compound is missing but I was able to get the Full question and missing compound . ( compound = copper sulfate )
answer : statement ; 2 , 3 and 5
Explanation:
The true statements regarding the coordination compound ( copper sulfate ) are :
The ligand must have at least one unshared pair of valence electrons in order to covalently bond with transition metal in the coordination compound ( statement 2 )Ethanol was used during crystallization of the coordination compound because the compound is soluble in ethanol ( statement 3 ) The colors of many coordination compounds are the result of light absorption by the d electrons on the transition metal ( statement 5 )During the coordination of compounds dative bonds exits between the transition metals and the Ligands molecules
Is water an acid, base, or neutral?
The bullet train was traveling at a speed of 200mi/hr for 2 hours. What
was the total distance traveled? *
O 100mi
O 01mi
O 40mi
O 400mi
Answer:
Distance is speed x time
So 200 x 2 =400mi
4. Calculate the volume of ammonia gas, at s.t.p., formed from 4.28 g of ammonium
chloride
List 2 ways that the increase in human population has had a negative impact on
the environment.
I
Object X carries a net negative charge. Danny touches object X and all of the excess negative charge leaves it. Danny effectively grounds object X by touching it.
Answer: B.) Object X Is A Conductor
Explanation: Since object X was able to lose all of its charge by being grounded, this means that its charges were able to move about freely. This strongly suggests that object X is a conductor. If object X had been an insulator, the ground would have had virtually no effect on its net charge.
How many carbon atoms are in 6.5 moles of carbon?
3.91 ×10²⁴ carbon atoms are in 6.5 moles of carbon. The smallest unit of matter that may be divided without producing electrically charged particles is the atom.
What is atom?The smallest unit of matter that may be divided without producing electrically charged particles is the atom. It is also the smallest piece of substance with chemical element-like characteristics. As a result, the atom serves as the fundamental unit of chemistry. Space makes up the majority of an atom.
The rest is made up of a cloud of electrons that are negatively charged surrounding a nucleus that is positively charged made up of protons and neutrons. Compared to electrons, which are the smallest charged particles in nature, the nucleus is small and dense. Electric forces, which link radicals to the nucleus of atoms, cause them to be drawn to any positive charge.
number of atoms= 6.5 × 6.022×10²³
=3.91 ×10²⁴
Therefore, 3.91 ×10²⁴ carbon atoms are in 6.5 moles of carbon.
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Balance the equation ___ CaCO3 -> ____ CaO + ____ CO2
Answer:
CaCO3 -> CaO + CO2
Explanation:
Woahhhh, did you balance it yourself just then?
Using the balanced reaction below, answer the following question:
2 Al + 3 ZnCl2 → 3 Zn + 2 AlCl3
How many moles of ZnCl2 are needed to react when 1.75 moles of AlCl3 form?
Answer:
Calculate the number of grams of AlCl3 produced from 2.5 moles of Cl2. The reaction between H2 and O2 produced 31.0 g of water. How many grams of O2 reacted?
Explanation:
If the empirical formula of an organic compound is CH20, then the molecular mass of the compound could be
A. 15g
B. 45g
c. 60g
D. 135g
At a certain temperature this reaction follows second-order kinetics with a rate constant of 14.1·M−1s−1 : →2SO3g+2SO2gO2g Suppose a vessel contains SO3 at a concentration of 1.44M . Calculate the concentration of SO3 in the vessel 0.240 seconds later. You may assume no other reaction is important. Round your answer to 2 significant digits.
Answer:
[tex][SO_3]=0.25M[/tex]
Explanation:
Hello there!
In this case, since the integrated rate law for a second-order reaction is:
[tex][SO_3]=\frac{[SO_3]_0}{1+kt[SO_3]_0}[/tex]
Thus, we plug in the initial concentration, rate constant and elapsed time to obtain:
[tex][SO_3]=\frac{1.44M}{1+14.1M^{-1}s^{-1}*0.240s*1.44M}\\\\[/tex]
[tex][SO_3]=0.25M[/tex]
Best regards!
For a multistep reaction the observed order of
the reaction is generally determined by the
1. stoichiometric coefficients of the net reaction.
2. ratio of reactant and product concentrations.
3. slowest reaction of the sequence.
4. time at which the concentrations of all
species are measured.
5. activation energy.
Answer: 3 slowest reaction of the squence
Explanation:
The order of reaction is obtained from the slowest step in the reaction.
An elementary reaction refers to any reaction that takes place in one reactive encounter. On the other hand, a multistep reaction occurs in several steps and involves multiple reactive encounters.
The rate determining step in a multistep reaction is the slowest step in the reaction sequence. The order of reaction is obtained from this slowest step in the reaction.
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0.329 M copper (II) nitrate was reacted with 0.528 M potassium carbonate as follows: Cu (NO subscript 3 )subscript 2 italic (a q italic )space plus space straight K subscript 2 CO subscript 3 italic (a q italic )rightwards arrow CuCO subscript 3 italic (s italic )space plus space 2 thin space KNO subscript 3 italic (a q italic )Determine the percent yield if 163.9 mL of each reactant were allowed to react, and a mass of 4.883 g of solid were obtained.
Answer:
73.33% is the percent yield
Explanation:
Percent yield is defined as:
Actual yield (4.883g) / Theoretical yield * 100
Based on the reaction:
Cu(NO₃)₂(aq) + K₂CO₃(aq) → CuCO₃(s) + 2KNO₃(aq)
1 mole of copper nitrate reacts per mol of potassium carbonate.
To solve this question we must find limiting reactant. With limiting reactant we can find the theoretical moles of solid produced and its mass as follows:
Moles Cu(NO₃)₂:
0.1639L * (0.329mol / L) = 0.0539 moles
Moles K₂CO₃:
0.1639L * (0.528mol / L) = 0.0865 moles
As the reaction is 1:1, the limiting reactant is Cu(NO₃)₂.
1 mol of Cu(NO₃)₂ produces 1 mol of CuCO₃. That means theoretical moles produced are 0.0539 moles. And the mass is:
Mass CuCO₃ -Molar mass: 123.55g/mol-
0.0539 moles * (123.55g / mol) = 6.659g of CuCO₃ is the theoretical mass
And percent yield:
4.883g / 6.659g * 100
73.33% is the percent yield