The number of radioactive nuclei in a particular sample decreases to one-eighth of its original number in 9 days. The half-life of these nuclei is 3 days.
According to radioactive decay law,
n(t) = No [tex]e^{-kt}[/tex]
where n is number at t and No is starting number
when t = 9, n/No = 1/8 = 0.125
so
0.125 = [tex]e^{-k9}[/tex]
ln 0.125 = -9 k
k = 0.231
So,
half life = [tex]t\frac{1}{2}[/tex] = 0.693/k
half life = [tex]t\frac{1}{2}[/tex] = 0.693/0.231
half life = [tex]t\frac{1}{2}[/tex] = 3days
Therefore, when the number of radioactive nuclei in a particular sample decreases to one-eighth of its original number in 9 days. The half-life of these nuclei is 3 days.
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A 0.137 mol of n2o gas occupies a volume of 846 ml at a pressure at 2.37 atm. what temperature is the gas?
The temperature of a 0.137 moles of N₂O gas occupying volume of 846mL at a pressure 2.37atm is 178.48K
An ideal gas equation is :
PV = nRT
Here: P = pressure of a gas (in atm)
V =volume of a gas(in Litre)
n = number of moles of a gas
R = universal gas constant ( 0.082 [tex]\frac{Latm}{molK\\}[/tex])
T = temperature of a gas( in kelvin)
calculation:
substitute the given values provided question in the equation.
2.37×0.846 = 0.137×0.082×T
T = 178.48K
Result : The temperature of a given N₂O gas is 178.48K.
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prove that liquid pressure (p)=phg.
I think it will be helpful for you
Explanation:
How much water ml a 8 m solution of naoh should be taken in order to obtain a 100 ml solution with a final concentration of 2.5 m?
The amount of water that should be taken in order to obtain a 100 ml solution with a final concentration of 2.5 m is: 31.25 ml
To solve this problem, the formula and the procedure that we have to use is:
c1 * v1 = c2 * v2
Where:
c1= concentration of the concentrated solutionv1 = volume of the concentrated solutionc2 = concentration of the diluted solutionv2 = volume of the diluted solutionInformation about the problem:
c1 = 8 mc2 = 2.5 mv2= 100 mlv1=?Applying the dissolution of concentrations formula and clearing the volume of the concentrated solution (v1) we get:
c1 * v1 = c2 * v2
v1 = (c2 * v2)/ c1
v1 = (2.5 m * 100 ml)/ 8 m
v1 = 31.25 ml
What is a solution?In chemistry a solution is known as a homogeneous mixture of two or more components called:
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The first eight ionization energies of a third row element are 1012, 1907, 2914, 4964, 6274, 21267, 25431, and 29872 kj/mol. Identify the element.
The third row element is phosphorus (P).
The ionization energy (Ei) is the minimum amount of energy required to remove the valence electron, when element lose electrons, oxidation number of element grows (oxidation process).
Nonmetals are far right in the main group and they have highest ionization energy, because they have many valence electrons.
Sixth ionization energy is much higher than fifth, atom has five valance electrons. Element in a third row tith five valence electrons is phosphorus.
Electron configuration for phosphorus: ₁₅P 1s² 2s² 2p⁶ 3s² 3p³.
Phosphorus lost five valence electron to form cation with stable electron configuration as noble gas neon (atomic number 10).
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What volume of a 0.700 x 10-3 M NaOH solution is needed to prepare 25.0 ml of 0.500
x 10-4 M dilute NaOH solution?
The volume of the 0.7×10⁻³ M NaOH solution needed is 1.79 mL
Data obtained from the questionThe following data were obtained from the question:
Molarity of stock solution (M₁) = 0.7×10⁻³ MVolume of diluted solution (V₂) = 25 mL Molarity of diluted solution (M₂) = 0.5×10⁻⁴ M Volume of stock solution needed (V₁) = ? How to determine the volume of stock solution neededThe volume of the stock solution needed can be obtained as follow:
M₁V₁ = M₂V₂
0.7×10⁻³ × V₁ = 0.5×10⁻⁴ × 25
Divide both side by 0.7×10⁻³
V₁ = (0.5×10⁻⁴ × 25) / 0.7×10⁻³
V₁ = 1.79 mL
Thus, the volume of the stock solution needed is 1.79 mL
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is found in all living things which make them organic.
What is the electron configuration of a carbon atom with an ionic charge of 1 ?
1s22s22p6
1s22s22p4
1s22s22p1
1s22s22p2
1s22s22p3
1s22s22p5
1s22s2
The correct option is option 5 that is 1s²2s²2p³.
Acc to the general electronic configuration of carbon is 1s²2s²2p².
The carbon is present at the 4th group of periodic table. the atomic number of carbon is 6 that means it contains 6 electrons , 6 protons and 6 neutrons.since the carbon have four electron in its last shell so it can formed four bonds to fulfill its octet. to complete the octet the atom must have 8 electron its valence shell and become a neutral atom.since carbon can shared their four electron with other atom to formed a compound through the covalent bond.But now the carbon contain the one ionic charge that means one extra electron is added to the carbon so the electronic configuration is changed.(As per the question) .Now the carbon has 7 electrons in its valence shell.the orbital are present inside the subshells and their are four types of orbitals that is S, P , D, F.filling of orbital with electron are done acc to the Hund's rule , since the carbon have only seven electron , so the filling start from S orbital(closest to the nucleus) with two electrons than two electrons are filled in 2S orbital and In P orbital (Px, Py, Pz), one electron is filled in 2Px and one electron is filled in 2Py and one electron is filled in 2Pz.this way the filling of electron are done,the orbitals are arranged acc to the energy level.
generally the carbon contains the six electrons but with ionic charge of 1 , the carbon contains seven electrons and these electrons are filled in the orbitals acc to the Hund's rule.
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The correct Option is 5 that is 1s²2s²2p³
The atomic number of carbon is six it means the carbon has six electrons and six protons in its valence shell.
Acc to that the general electronic configuration of carbon is 1s²2s²2p ².
since the carbon has four electron in its last shell so it can share their electron with other atom to formed the compound to complete its octet and become the neutral compound.
The orbitals present in the subshell and to fill the orbitals with electron we follow HUND's RULE.
acc to HUND's rule , every orbital are filled first filled with one electron then filled with second electron so as to make doubly occupied the orbital.
There are fours types of orbitals S,P,D,F.
In the S orbital has capacity to filled only two electrons , 2 S orbital filled 2 electrons The P orbitals has capacity to filled 6 electrons divided into 2px , 2py, 2pz (Each contain two electrons).
Since as per the question one ionic charge are added so the total number of electrons in the carbon is 7 acc to that the electrons are distributed in the orbitals.
1S² = 2 electrons
2S²= 2 electrons
2px = 1 electron
2py= 1 electron
2pz = 1 electron
Generally the carbon contain 6 electron but with ionic charge the total number of electron becomes 7 and the filling of orbital follow the Hund's rule.
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When water dissolves a substance, weak charges on water molecules attract oppositely charged portions of the substance, pulling them out into solution. Which property of water accounts for this occurrence?.
When water dissolves a substance, weak charges on water molecules attract oppositely charged portions of the substance, pulling them out into solution. The property of water that accounts for this occurrence is the polarity of water.
The water molecule is made up of one oxygen atom and two hydrogen atoms. The three atoms are arranged in such a way that the hydrogen atoms carry a partial positive charge, and the oxygen atom carries a partial negative charge.
Thus, there is a tendency for the partial negative oxygen atom to be attracted to the positively charged portion of another substance, and the partial positive hydrogen atoms to be attracted to the negative portion of the substance.
This attraction is called polarity. A substance is said to be polar when it carries both a positive and negative charge in its neutral state. Hence water dissolves a substance when weak charges on the water molecule attract the oppositely charged portion of that substance due to its polarity.
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2. convert 4.22 cL to mL
Answer:
1 cl =10 ml
so
4.22cL= 4.22×10= 42.2 mL
What are the end products of photosynthesis? oxygen and carbohydrate water and carbon dioxide water and oxygen carbohydrate and water
The end products of photosynthesis are oxygen and carbohydrate.
The overall balanced eqation for photosynthesis reaction:
6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
CO₂ is carbon dioxide or carbon(IV) oxide
H₂O is water molecule
C₆H₁₂O₆ is carbohydrate
O₂ is oxygen molecule
Light energy is transformed into a chemical energy, that is stored in a carbohydrate molecules (glucose), which are synthesized from carbon dioxide and water.
Plants (not animals) convert a solar energy into the chemical energy of sugars (food).
The pigment chlorophyll absorbs one photon and loses one electron (it passed throw an electron transport chain) in the light-dependent reactions.
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Aluminum has a density of 2.70 g/ml. calculate the mass (in grams) of a piece of aluminum having a volume of 297 ml
The net ionic equation for the reaction that occurs when aqueous solutions of sodium hydroxide and hydrocyanic acid are combines is
OH−(aq)+HCN(aq)→CN−(aq)+H2O(l)
What is ionic equation?
A chemical equation known as an ionic equation expresses the electrolytes in aqueous solution as dissociated ions.
Deprotonation of the acid by the hydroxide ion from the base occurs when weak acids like hydrocyanic acid are mixed with strong bases like sodium hydroxide. The conjugate base of the acid and water is created as a result of this reaction.
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The number of calories needed to raise the temperature of 32 g of water from 12 °c to 54 °c is.
1349.13 calories are required in order to raise the temperature of 32g of water from 12°C to 54°C.
what is specific heat capacity?
"The amount of heat required to change the temperature of a unit mass of the substance by one degree" is the definition of specific heat capacity for any substance. This is expressed as: Specific heat capacity is a sort of thermal inertia since it shows how resistant a substance is to changes in temperature.
Water has a specific heat capacity of about 4.2 J/g°C. As a result, to increase 1 gramme of water by 1 degree Celsius, 4.2 joules of energy are required.
By formula,
Q = mcΔT = 32*4.2*42 = 5644.8 J
One calorie= 4.184 joules
thus, Q = 5644.8/4.184 calorie = 1349.13 calories.
Thus 1349.13 calories are required in order to raise the temperature of 32g of water from 12°C to 54°C.
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Nonpolar amino acid residues are typically found in the interior of globular proteins like trypsin. Which chemical force is most directly responsible?.
The chemical force most directly responsible in the given case is hydrophobic interactions.
The interactions between hydrophobes and water, or low water-soluble compounds, are illustrated by the hydrophobic interactions. Nonpolar hydrophobes often have a longer carbon chain than polar molecules and do not interact with the water molecules. By removing a peptide from the N terminus of trypsinogen, it can become trypsin, which allows a salt bridge to develop between the new N-terminal.
The trypsin "activation domain" undergoes a conformational shift in response to the development of this salt bridge, resulting in the establishment of the oxyanion hole and S1 binding site. Trypsinogen activation thus seems to be an illustration of protein folding influenced by electrostatic interactions. The activation domain receives 5 kcal/mol of stabilization energy through hydrophobic interactions with the Ile16 side chain.
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How many ml of a 5.0 m solution of sodium borate must be added to a 200 ml solution of 50 mm boric acid in order for the ph to be 9.6?
4.6 ml of a 5.0 M solution of sodium borate must be added to a 200 ml solution of 50 mM boric acid in order for the pH to be 9.6.
Henderson–Hasselbalch equation for buffer solution:
pH = pKa + log(cs/ck)
pH = 9.6; pH of the buffer solution of sodium borate and boric acid
pKa = 9.24
log(cs/ck) = 9.6 - 9.24
log(cs/ck) = 0.36
cs/ck = 2.29; ratio of sodium borate and boric acid
nk = 0.05 M × 0.2 l
nk = 0.01 mol; amount of boric acid
Vs = 200 ml ÷ 100 × 2.29
Vs = 4.6 ml; volume of sodium borate
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If+a+250-ml+solution+of+ethanol+in+water+is+prepared+with+4+ml+of+absolute+ethanol,+what+will+be+the+concentration+of+ethanol+in+%+v+/v?
% v/v = (volume of ethanol/total volume) x 100%
% v/v = 4 ml/250 ml x 100 % 1.6 % (v/v) ethanol 98.4% water 1.6% ethanol
Mixtures of ethanol and water are not ideal (i.e. have linear properties) so you cannot mix 4 mL of ethanol with 246 mL of water to get a 250 mL mixture and precious 100 But also 250ml contains the same amount of ethanol as the previous 4ml. But the volume is 250/4 = 62.5 times larger. This is therefore the dilution factor by volume.
The concentration of a substance is the amount of solute present in a given volume of solution. Concentration is usually expressed in molarity, defined as the number of moles of solute in 1 L of solution.
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What would happen if styrene taken directly from a commercial bottle was used in this reaction?
Direct usage of styrene from a commercial bottle will result in a radical reaction known as polymerization.
In the process of polymerization, monomer molecules are brought together chemically to create chains of polymer or three-dimensional networks.
Easily polymerizing to polystyrene, styrene does so by a reasonably common free radical chain process. The polymerization will start either with heat or using initiators. As initiators thermally break down, active free radicals are created that are useful for igniting the polymerization reaction.
There would not be any polymerization unless a lot of tert-butyl peroxybenzoate was employed. Commercial styrene contains tert-butycatechol, which functions as a scavenger of radicals to transform radicals into non-radicals and halt the start of polymerization.
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A combustion device was used to determine the empirical formula of a compound containing only carbon hydrogen and oxygen. A 2.62 g sample of unknown produced 2.45 g carbon dioxide and 1.50 g water. What is the empirical formula of a compound
The empirical formula of the compound is C₂H₃O₄.
Mass of composition of the atoms in the compound
mass of carbon in the carbon dioxide, C = (12 x 2.45)/44 = 0.668 g
note molar mass of carbon dioxide = 44 g/mol
mass of hydrogen in the water, H = (1 x 1.5)/18 = 0.083 g
note molar mass of water = 18 g/mol
mass of oxygen, O = 2.62 g - (0.668g + 0.083 g) = 1.869 g
Molar composition of the atomsC = 0.668 g / 12 = 0.056 mole
H = 0.083 g/ 1 = 0.083 mole
O = 1.869 g/16 = 0.1168 mole
Divide through by the smallest number of mole
C = 0.056/0.056 = 1
H = 0.083/0.056 = 1.5
O = 0.1168/0.056 = 2
C = 1 x 2 = 2
H = 1.5 x 2 = 3
O = 2 x 2 = 4
C₂H₃O₄
Thus, the empirical formula of the compound is C₂H₃O₄.
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The reaction of 9.90 g of carbon with excess o2 yields 11.6 g of co2. what is the percent yield of this reaction?
The % yield of this reaction is 31.95%
Given:
Mass of C = 9.90g
Actual yield of CO2 (AY) = 11.6g
To Find:
% yield = ?
Formula:
% yield = (actual yield / theoretical yield) x 100
Calculations:
C + O2 –> CO2
mols C = mass C (g) / atomic mass C (g/mol)
mols C = 9.90 / 12 = 0.825 mols
mols CO2 = 0.825 since 1 mol CO2 for each mol C.
Theoretical CO2 yield = mols CO2 x molar mass CO2
TY = 0.825 x 44.01
TY = 36.308g
% yield = (AY / TY) x 100
% yield = (11.6 / 36.308) x 100
% yield = 31.95%
Result:
31.95% is the yield of CO2 in this reaction.
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PLEASEEEE HELPPPP I’ll make you Brainlys Summary
Now, create of summary of what you've learned.
1. Complete the table below for protons, neutrons, and electrons. Respond with a Y for yes or N of no.
1
2
3
***
***
***
Question
Score: 0/4
Identifies Element?
Affects Mass?
Affects Charge?
***
Proton
***
Neutron
***
Electron
***
Answer:
Explanation:
For the first row, only protons identify an element. For the second row, protons and neutrons affect mass. For the third row, protons and electrons affect charge.
Coffee has a ph of approximately 5. 0. What results would you predict if we added lactase to a solution of milk and coffee? would glucose be produced? provide your rationale.
Lactose contains sugar and glucose, which is found in lactose, glucose will be formed when coffee is added to milk and then lactose is added to the coffee and milk combination.
Because milk contains calcium, it is white in colour and contains the known sugars lactose and glucose. Lactose, a type of sugar present in milk, turns into glucose when combined with coffee.
Farmers dry the brownish bean-shaped coffee seed, which is then ground into a fine powder and combined with milk and sugar to make coffee. In general, Brazil and other nations are where you may find coffee.
Because lactose contains sugar and glucose, when coffee is added to milk and then lactose is added to the coffee and milk solution, glucose will be created.
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Read and record the temperature on each of these thermometers.
100
09
50
40
30
20
Ro
°C
100
90
06
70
60
50
40
30
20
10
100
80
70
60
50
40
30
220
°C
100
06
50
100-
90
08
70
60
eel heat and measure
40
°C
100
30
20
100
80
50
°℃
-100
40
R20
Answer:
Most thermometers have two scales for temperature, Fahrenheit and Celsius. Read the numbers for °F (degrees of Fahrenheit). Each long line is for 1°F temperature. The four shorter lines between each long line are for 0.2°F (two tenths) of a degree of temperature.
Explanation:
when stored energy burns what is it converted/transformed to
Answer:
The energy changes into heat and light energy.
Explanation:
pls mark brainliest
What is the net ionic formula if aqueous hypochlorous acid and aqueous calcium hydroxide react?
Calcium hypochlorite is created when aqueous hypochlorous acid and aqueous calcium hydroxide combine.
What is a ionic formula?
The positive ion, also known as a cation, comes first in the formula of an ionic compound, followed by the negative ion, also known as an anion. A balanced formula has a neutral electrical charge, or zero net charge. Ionic compounds can be described using chemical formulas, which show the proportions of interacting components present in an ionic solid or salt.
The term "neutralisation reaction" is typically used to describe the reaction between an acid and a base where salt and water are the end products.In this query, aqueous hypochlorous acid is used as the acid and aqueous calcium hydroxide as the base.Due to the exchange of cations and anions caused by the acid and base, the reaction passes through a double displacement reaction.The net ionic equation primarily demonstrates how water is created because the salt product is typically soluble.Calcium hypochlorite is created when aqueous hypochlorous acid and aqueous calcium hydroxide combine.The graphic that is associated to the solution contains the reaction's balanced equation.To learn more about ionic formula from the given link below,
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iv. Write down the balanced chemical equation for the reaction: a. after bubbling air through the lime water. b. after the disappearance of pink colour of sodium hydroxide reacting with hydrochloric acid and phenolphthalein.
Answer:
sodium hydroxide + Hydrochloric acid -> Sodium chloride + Water
Explanation:
sodium hydroxide + hydrochloric acid = neutral solution
[Base]. [Acid]
This turns the phenophthalein Colourless
The dye ________ turns ________ in the presence of acid products and is included in fermentation broth for some diagnostic tests.
The dye phenol red turns yellow in the presence of acid products and is included in fermentation broth for some diagnostic tests.
Phenol is an ordinary pH indicator and at a lower pH value i.e >7, Phenol red is a colorless compound. It is used to perform some diagnostic tests in the fermentation process.
The compound exhibits a sudden change in color as a result of a higher ph value.
It is composed of both negatively charged and positive charged particles i.e sulfate and ketone groups.
When it reacts with an acid the pH of phenol solution ranges between 6-8 and shows a quick transition from red to yellow indicating a pH change.
The transition from red to yellow is due to the loss of proton by the ketone group.
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Plsssss help me I rlly need an A PLSSSSS When the ground is porous water is able to seep through as ground water.
True
False
Answer:
True
Explanation:
Water that seeps through rocks and soil into the ground is called groundwater. Freshwater is stored underground as groundwater. The total volume of open space in which the groundwater can reside is porosity. Porosity determines the amount of water that a rock or sediment can contain. In sediments or sedimentary rocks, the porosity depends on grain size, the shapes of the grains, the degree of sorting, and the degree of cementation. The combination of water storage (porosity) and flow (permeability) makes a good aquifer—a rock unit or sediment that contains usable groundwater. Well-sorted sediments (i.e., uniform grain size) have higher porosity because smaller sediment particles do not fill in the spaces between the larger particles.
which substance does not have a definite shape, color, or texture?
I believe gases do not have a definite shape, color, or texture.
A solid has definite volume and shape, a liquid has a definite volume but no definite shape, and a gas has neither a definite volume nor shape
So the answer is a gas
The pka values for the amino acid glycine are: pka,1 = 2.3 and pka,2 = 9.6. at what ph value or ph values would glycine be most effective as a buffer?
The pka values for the amino acid glycine are: pka,1 = 2.3 and pka,2 = 9.6. at pH = 2.3 and pH 9.6 value.
What is ph ?The term pH, which originally stood for "potential of hydrogen" (or "power of hydrogen"), is used in chemistry to describe how acidic or basic an aqueous solution is. Greater pH values are seen in basic or alkaline solutions than acidic solutions.
Since hydrogen ions are logarithmic, the pH scale shows how many of them are present in a solution in inverse proportion.
M = mol dm3, where. Acidic solutions have a pH under 7, while basic solutions have a pH over 7, at a temperature of 25 °C (77 °F). At this temperature, solutions with a pH of 7 are neutral (i.e., have the same amount of H+ and OH- ions, like pure water), meaning they don't react with one another. Temperature has an impact on the pH's neutral value.
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If you wear contact lenses, why should you remove them while you are in the laboratory?
A)
They can dry out your eyes while you are doing your experiment.
B)
They can hold chemicals that accidentally splash into your eye next to your eye and cause permanent damage.
C)
They can fall out if you do not remove them.
D)
None of the above
Please select the best answer from the choices provided
A
B
C
D
Contact lenses have adhesive nature
In laboratory perhaps any chemical rushes into your eye then the contact lenses can catch and hold them there
which can cause severe damage to the eye lids
option B is correctWhat mass (in g) of potassium chlorate is required to supply the proper amount of oxygen needed to burn 123.7 g of methane?
So amount of KClO3 required = 123.7*5/3 gms = 206.166 gms.
What amount of KClO3 will be used in the experiment? How long should it be heated?shows how to set the KClO3 crucible on a clay triangle with the cover slightly ajar. Heat the crucible containing the powders gently for about 8 minutes, then vigorously for 10 minutes. Potassium chlorate (KClO3) is a powerful oxidising agent with numerous applications. It's in explosives, fireworks, safety matches, and disinfectants, among other things. You may have used it to generate oxygen in the lab as a high school or college chemistry student. While it is not the most efficient chemical reaction, making potassium chlorate is as simple as boiling bleach, cooling it, and mixing it with a saturated solution of salt substitute in water. Because potassium from the salt substitute displaces sodium from the sodium chlorate formed by boiling the bleach, the synthesis works.
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