Answer:
0.296 mg
Explanation:
8.00/2.90 half lives have passed, so this means the remaining mass is
[tex]2.00 {(0.5)}^{8.00 \div 2.90} [/tex]
which is about 0.296 mg.
The amount of polonium remaining after 8.00 years is 0.296 mg. This is obtained by using rate law of first order kinetics.
What is the rate law of first order kinetics and the half-life of the compound?The expression for the rate law for first order kinetics is
k = [tex]\frac{2.303}{t}log\frac{a}{a-x}[/tex] years⁻¹
Where,
k - rate constant
t - time passed by the sample
a - initial amount of the reactant
a-x - final amount of the reactant
The expression for the half-life of the compound is
[tex]t_{\frac{1}{2}}=\frac{0.693}{k}[/tex] years
Calculating the amount of polonium remained after 8.00 years:Given that,
A Polonium-208 is an alpha emitter with a half-life of 2.90 years.
I.e., [tex]t_{\frac{1}{2}}[/tex] = 2.90 years
Then,
2.90 = (0.693)/k
⇒ k = (0.693)/(2.90) = 0.2389 years⁻¹
Then,
for t = 8.00 years,
Since we have rate law of first order kinetics as
k = [tex]\frac{2.303}{t}log\frac{a}{a-x}[/tex]
⇒ k = (2.303/8.00) log(a/a-x)
Where the initial amount of the reactants is a = 2.00 mg
So,
k = 0.287 log (2.00/a-x) (a-x is the final amount of the reactants)
⇒ 0.238 = 0.287 log(2.00/a-x)
⇒ (0.238/0.287) = log(2.00/a-x)
⇒ 0.829 = log(2.00/a-x)
⇒ (2.00/a-x) = [tex]10^{0.829}[/tex] = 6.745
⇒ (a-x) = 2.00/6.745 = 0.296 mg
Therefore, the remaining polonium is 0.296 mg after 8.00 years.
learn more about first order kinetics here:
https://brainly.com/question/21681256
#SPJ4
500 ml of nitrogen and 500 ml of hydrogen are kept together in one vessel at the same constant temperature and pressure. Which of the following is true for their number of molecules?
A. NN2 > NH2
B. NN2 < NH2
C. NN2 = N H2
D. NN2 + NH2 = 1 mole
The number of molecules of nitrogen will be the same as the number of molecules of hydrogen. The correct option is C.
What is Avogadro's law?The law states that different gases of the same volume stored at the same temperature and pressure will contain the same number of molecules.
Going by Avogadro's law, 500 ml of nitrogen and 500 ml of hydrogen kept together in one vessel at the same constant temperature and pressure will have the same number of molecules.
More on Avogadro's law can be found here: https://brainly.com/question/4133756
#SPJ1
Increasing which factor will cause the gravitational force between two objects to decrease?
weights of the objects
distance between the objects
acceleration of the objects
masses of the objects
Answer:
mass increase!
Explanation:
<3
Answer:
b.distance between the objects
Explanation:
If you pull objects apart from each other they don't have as strong of a gravitational pull. think of it like a magnet the heavier the magnets the more power they can hold, the bigger they are the more surface area they have, and when you pull 2 magnets apart they slowly come weaker to each other.
Experiments were done on a certain pure substance ex to determine some of his properties there’s a description of each experiment and the table below the side whether the experiment was a physical or chemical property
Answer:
1.) Physical
2.) Physical (probably)
3.) Chemical
Explanation:
Physical changes are changes to substances in which the intramolecular structure does not change. The intermolecular bonds (bonds between molecules) may change, but the actual chemicals involved are not altered.
Chemical changes occur when intermolecular bonds are broken/formed, changing the old substance into something new. Chemical reactions are taking place and the ratio of the elements in molecules are changing.
1.) Melting is an example of a physical change. When melting occurs, the intermolecular bonds between molecules are breaking in response to the introduction of more heat. However, the substance is still the same substance (ex. ice melting is still water as H₂O has not been changed). In this example, scientists are most likely calculating velocity.
2.) Because the original substance is able to be completely removed from the water in the flask, this is probably just a physical change. I say probably because no changes are really occurring here. It is unclear but not probably that any reactions are taking place between the water and the sample as they are easily separated. This may be an example of (can't decide) depending on how must they want you to assume. The property being measured is probably density.
3.) While dissolving the sample was an example of a physical change because just the state of matter changed, when it reacts with sodium hydroxide, a chemical change occurs. Most likely, new bonds are being formed between the elements in the original sample and the elements in sodium hydroxide. This is what allows scientists to measure the pH of a solution.
mention one real life significance of the covalent bond.
Answer:
it helps in respiration
calculate the electrons in 2.3 kg sodium
Answer:
6.627 x10^26 electrons
Explanation:
Each Na atom has 11 electrons
Mole weight = 22.989 gm/mole
2300gm /22.989 gm/mole * 6.022 x 10^23 atoms/mole * 11 electrons/atom
= 6.627 x 10 ^26 electrons
i will mark brainliest. Calculate the wavelength corresponding to a frequency of 98.8MHzl
Answer:
3.0395m
Explanation:
What type of system is a home, school, or room?
Answer:
room
Explanation:
because it'd in your house and u go there everyday and sleep and live there
A helium-filled balloon has a volume of 10 000 L at 20°C. Determine the volume of the
gas at 25 °C
Answer:
12,500 L
Explanation:
Because you are dealing with volume and temperature, you need to Charles' Law to find your missing value. The equation looks like this:
V₁ / T₁ = V₂ / T₂
In this equation, "V₁" and "T₁" represent the initial volume and temperature. "V₂" and "T₂" represent the final volume and temperature. You can plug the given values into the equation and simplify to find the final volume of the gas.
V₁ = 10,000 L V₂ = ? L
T₁ = 20 °C T₂ = 25 °C
V₁ / T₁ = V₂ / T₂ <----- Charles' Law equation
(10,000 L) / (20 °C) = V₂ / (25 °C) <----- Insert values
500 = V₂ / (25 °C) <----- Divide 20 from 10,000
12,500 = V₂ <----- Multiply both sides by 25
A mixture of He , Ar , and Xe has a total pressure of 3.00 atm . The partial pressure of He is 0.200 atm , and the partial pressure of Ar is 0.200 atm . What is the partial pressure of Xe ? Express your answer to three significant figures and include the appropriate units.
The partial pressure of Xe is 2.60atm
The sum of the partial pressures is equal to the total pressure. Ptotal = P1 + P2 + P3... .To calculate the partial pressure of one of the components of a mixture, subtract the sum of known partial pressures of the other components from the total pressure.
Given the values of
PHe=0.20 atm
PAr=0.20 atm
Ptotal=3.00 atm
We need to find PXe
Solution: Determine the sum of the partial pressures of helium and argon, then subtract the sum from the total pressure.
PHe+PAr =0.20 atm + 0.20=0.400 atm
PXe=3.00atm−0.400=2.60 atm
Each gas that makes up a mixture of gases has a partial pressure, which is the notional pressure of that gas as if it alone filled the original combination's complete volume at the same temperature.
According to Dalton's Law, a perfect gas mixture's total pressure equals the sum of its constituent gases' individual partial pressures.
The thermodynamic activity of a gas's molecules is gauged by its partial pressure.
Gases react, disperse, and dissolve based on their partial pressures rather than the concentrations they have in liquids or other gas combinations.
This general characteristic of gases holds true in biological chemical interactions involving gases.
Hence the partial pressure of Xe is 2.60atm
Learn more about partial pressure here
https://brainly.com/question/19813237
#SPJ4
In an electrolytic cell, the electrode that acts as a source of electrons to the solution is called the __________; the chemical change that occurs at this electrode is called __________.
In an electrolytic cell, the electrode that acts as a source of electrons to the solution is called the cathode; the chemical change that occurs at this electrode is called reduction.
Define Electrolyte:-An electrolyte is a material that separates into charged ions when it is in contact with water. Cations are positively charged ions. Anions are ions that are negatively charged. A substance that may conduct an electric current when melted or dissolved in water is known as an electrolyte.
Electrochemical cellThere are three main categories of electrochemical cells. the galvanic cell, the concentration cell, and the electrolytic cell. These cells all share the same four fundamental components. These are the elements
The electrolyte serves as the conduit for current flow between the anode and the cathode. In an aqueous solution, it normally is homogeneous, but in moist soil, the concentration or kind of dissolved compounds may vary locally.The anode, which can conduct electricity and is in contact with the electrolyte, corrodes when it combines with the chemicals in the electrolyte.A metal also contacts the electrolyte at the cathode. It is protected from corrosion rather than corroded.Anode and cathode are connected by the conductor, which also completes the circuit.Learn more about Electrochemical cells here:-
https://brainly.com/question/25749323
#SPJ4
What is the temperature of 0.460 mol of gas at a pressure of 1.2 atm and a volume of 12.5 L ? Express your answer using two significant figures.
The temperature is 370K.
The volume of a given fuel pattern is immediately proportional to its absolute temperature at regular pressure (Charles's law). The volume of a given amount of fuel is inversely proportional to its pressure whilst temperature is held steady (Boyle's regulation).
Density is immediately proportional to stress and indirectly proportional to temperature. As stress increases, with temperature constant, density will increase. Conversely when temperature increases, with strain regular, density decreases.
The equations describing those legal guidelines are unique cases of the best gasoline regulation, PV = NRT, wherein P is the pressure of the gas, V is its extent, n is the number of moles of the gas, T is its kelvin temperature, and R is the ideal (common) gas constant.
Learn more about pressure here: https://brainly.com/question/25736513
#SPJ4
The conversion of 1 mol of fructose 1,6-bisphosphate to 2 mol of pyruvate by the glycolytic pathway results in a net formation of:
Net Product formed:
The conversion of 1 mol of fructose 1,6-bisphosphate to 2 mol of pyruvate by the glycolytic pathway results in a net formation of 2 mol of NADH and 4 mol of ATP.
Glycolysis:
The energy-intensive stages also known as the first half of glycolysis. It divides the six-carbon sugar molecule evenly into two three-carbon molecules. The energy-releasing stages, or the second half of glycolysis, draw energy from the molecules and store it as ATP and NADH, the reduced form of NAD.
Two pyruvate molecules form the final product of glycolysis, which begins with glucose and two ATP molecules and two NADH molecules are gained by the cell as a net result.
The first half of the process requires the utilization of two ATP molecules to set up the six-carbon ring for cleavage. But since this pathway is starting from fructose 1,6-bisphosphate, the utilization step is omitted thus four molecules of ATP and two molecules of NADH are produced in total.
Learn more about the glycolysis here,
https://brainly.com/question/27178607
#SPJ4
The half-life of 131I is 80 days. How much of a 500.0 mg sample remains after 3 half lives?
Answer:
62.5 mg
Explanation:
Just multiply the original amount by 1/2 three times:
500 mg x 1/2 x 1/2 x 1/2 = 62.5 mg
The electron configuration of an element is 1s22s22p¹. How many valence electrons does the element have
a) 1
b) 2
c)3
d)4
Answer:
[tex]\huge\boxed{\sf 3 \ electrons}[/tex]
Explanation:
Electronic configuration:[tex]1s^22s^22p^1[/tex]
The outermost/valence shell is the second one, seeing from the electronic configuration.
Valence electrons:= 2 + 1 = 3 (electrons are raised to the power in the electronic configuration)
Since, the valence shell here is 2, the electrons of second shell will be counted as valence electrons.
[tex]\rule[225]{225}{2}[/tex]
Classify the chemical reaction: Cl₂O5 + H₂O → 2HCIO3
The reaction is an addition reaction.
What is an addition reaction?Addition reactions are chemical reactions involving 2 or more reactants reacting to produce a single product.
Addition reactions are different from decomposition reactions. In the latter, a single reactant decomposes to give two or more products.
In the illustrated reaction, Cl₂O5 and H₂O react together to form a single product, HCIO3.
More on addition reactions can be found here: https://brainly.com/question/13669873
#SPJ1
Which type of molecule is shown below?
O A. Alkane
•
B. Cyclic alkane
•
C. Alkene
O
D. Alkyne
Answer:
[tex]\huge\boxed{\sf Alkene}[/tex]
Explanation:
The molecule shown is an Alkene, since:
There is a double bond between the carbon atoms.[tex]\rule[225]{225}{2}[/tex]
A 2.0 L party balloon at 98 kPa is taken to the top of a mountain where the pressure is 75
kPa. Assume that the temperature and chemical amount of the gas remain the same,
determine the new volume of the balloon.
Answer:
2.61 L
Explanation:
p1v1 = p2v2
p1v1 / p2 = v2
98 * 2 / 75 = v2 = 2.61 L
What is the chemical formula for acetic acid?
O CHO
O C₂H4O2
O C₂OH
O C₂0₂H
Answer:
The answer is C2H4O2
The vapor pressure of water at 25c is 23.76 torr. if 1.25g of water is enclosed in a 1.5l container, will any liquid be present? if so, what mass of liquid?
Mass of liquid present in the container:
Yes, the liquid will be present, and of 1.2481 g
Calculation:
Given:
Volume = 1.5L
Temperature = 25 + 273 = 298K
P = 23.76 torr = 0.0312 atm
Using the ideal gas equation:
PV = nRT
Where:
P: PressureV: Volumen: number of molesR: gas constant = 0.0821 L atm [tex]K^{-1}[/tex] [tex]mol^{-1}[/tex]T: Temperaturemaking n subject of formula:
n = [tex]\frac{PV}{RT}[/tex]
By putting all the values in the given equation, we get,
n = 0.0312 x 1.5 / 0.0821 x 298
n = 0.0019 moles
So, 0.00189 are moles of water in the vapor
Now, subtract 1.25g of water from moles of water vapor, and we will get the mass of the liquid left,
1.25 - 0.0019 = 1.2481 g
Learn more about the ideal gas equation here,
https://brainly.com/question/14478699
#SPJ4
PLEASE HELP !!!
Which two elements have the same number of dots around their chemical symbols in their electron dot diagrams.
The two elements have the same number of dots around their chemical symbols in their electron dot diagrams are: (C). P and As
Meaning of chemical symbolsChemical symbol can be defined as a representation of an element using letters.
Chemical symbol are given to each element distinctively and this is an easier way to represent an element.
Some examples of chemical symbols are; O for oxygen, Zn for zinc, and Fe for iron etc.
In conclusion, The two elements have the same number of dots around their chemical symbols in their electron dot diagrams are: (C). P and As
Learn more about Chemical symbol: https://brainly.com/question/15045637
#SPJ1
What would be the vital capacity be for a man that has a tidal volume of 500mL, a residual volume of 1100 mL, an expiratory reserve of 1100 mL and an inspiratory reserve of 3000 mL
The vital capacity will be 4600ml.
What is vital capacity?The highest amount of air a person can inhale following their maximal exhalation is known as their vital capacity. It is equivalent to the total of the inspiratory, tidal, and expiratory reserve volumes. It roughly corresponds to Forced Vital Capacity. A wet or conventional spirometer can assess a person's vital capacity.
Normal people have a 3 to 5-liter vital capacity.
It enables simultaneous inhalation of the greatest possible volume of clean air and exhalation of the greatest possible volume of stale air. So, by increasing gaseous exchange between the body's various tissues, it improves the amount of energy available for bodily function.
VC = TV₊IRV₊ERV
where,
VC = Vital capacity
TV = Tidal volume
IRV = inspiratory reserve volume
ERV = expiratory reserve volume
VC = 500 ₊ 3000 ₊ 1100
VC = 4600ml
Therefore, the vital capacity will be 4600ml.
To know more about vital capacity refer to: https://brainly.com/question/14877276
#SPJ4
How many H2O molecules are there in 4.5 g of water (see picture)
What is the empirical formula for a compound if a sample contains 3.72 g of p and 21.28 g of cl? pcl5 pcl3 p2cl10 p2cl5
Answer:
A.) PCl₅
Explanation:
To determine the empirical formula, you need to (1) identify the atomic masses of both elements (from the periodic table), then (2) convert each element from grams to moles (via atomic masses), then (3) divide both elements by the smallest molar value of both, and then (4) construct the empirical formula.
(Step 1)
Atomic Mass (P): 30.974 g/mol
Atomic Mass (Cl): 35.453 g/mol
(Step 2)
3.72 g P 1 mole
--------------- x ------------------ = 0.120 mole P
30.974 g
21.28 g Cl 1 mole
----------------- x ------------------- = 0.600 mole Cl
35.453 g
(Step 3)
Because 0.120 mole is smaller than 0.600 mole, you need to divide both elements by this value to determine the ratio of the elements in the empirical formula.
0.120 mole P / 0.210 mole = 1.00 mole P
0.600 mole Cl / 0.210 mole = 5.00 moles Cl
(Step 4)
The molar value of each element represents the amount of each element in the formula. This value shows itself in the form of subscripts in the formula. This makes the correct empirical formula:
PCl₅
The Ksp of Al(OH)3 is 2.0 x 10-31 at 298 K. What is \DeltaGo (at 298 K) for the precipitation of Al(OH)3 according to the equation below?
Al3+(aq) + 3OH- (aq) -> Al(OH)3 (s)
ΔG° = -RT ln K
ΔG° = -RT ln 1/Ksp (reverse reaction, solid (Al(OH)₃ not count for equilibrium constant-K)
ΔG° = -RT ln 1/Ksp
ΔG° = -8.314 x 10⁻³ x 298 ln 1/(2 x 10⁻³¹)
ΔG° = -175.132 kJ/mol
D. how many milliliters of a 0.8 m solution of citric acid would be needed to react with 15 grams of baking soda
The volume of 0.8 M solution of citric acid required would be 75mL.
Given:
Concentration of citric acid =0.8M
Mass of baking soda = 15 g
Balanced chemical equation for the reaction of baking soda(NaHCO₃ ) with citric acid (C₆H₈O₇) is:
C₆H₈O₇ + 3NaHCO₃ -----> 3H₂O + 3CO₂ + Na₃C₆H₅O₇
Therefore, 1 mole of citric acid needs 3 moles of baking soda
Molar mass of baking soda = 84g/mol
No. of moles of baking soda = mass of baking soda / molar mass of baking soda = 15g ÷ 84g/mol = 0.178 moles
Thus no. of moles of citric acid required = (1 ÷ 3) × 0.178mole =0.06mole
Molarity = no. of moles of / volume (in mL) x 1000
Volume of citric acid solution required= (0.06mole ÷ 0.8M) × 1000ml
=75ml
Learn more about molarity here:
https://brainly.com/question/8732513
#SPJ4
2. A chemical analysis of a sample provides the following elemental data:
364.8 g C
61.2 g H
324.0 g 0
Determine the empirical formula for this compound.
Answer:
C3 H6 O2
Explanation:
first divide their mass by their respective molar mass, we get:
30.4 moles of C
61.2 moles of H
20.25 moles of O
now divide everyone by the smallest one of them then we get
C= 1.5
H= 3
O= 1
since our answer of C is not near to any whole number so we will multiply all of them by 2
so,
C3 H6 O2 is our answer
Using a chemical equation to find moles of the product for moles of reactant
Answer:
0.10 moles H₂O
Explanation:
The unbalanced equation:
NH₃ (g) + O₂ (g) ----> NO (g) + H₂O (g)
Reactants: 1 nitrogen, 3 hydrogen, 2 oxygen
Products: 1 nitrogen, 2 hydrogen, 2 oxygen
The balanced equation:
4 NH₃ (g) + 5 O₂ (g) ----> 4 NO (g) + 6 H₂O (g)
Reactants: 4 nitrogen, 12 hydrogen, 10 oxygen
Products: 4 nitrogen, 12 hydrogen, 10 oxygen
Now that the reaction is balanced, you can use the coefficients of the desired molecules to construct the mole-to-mole ratio. This ratio should be multiplied by the given value (0.085 moles). It is important to arrange the ratio in a way that allows for the cancellation of units (the desired unit should be in the numerator). The final answer should have 2 sig figs to match the given value.
0.085 moles O₂ 6 moles H₂O
------------------------- x ------------------------ = 0.10 moles H₂O
5 moles O₂
A mixture of 0.0636 g of hydrogen and 0.0315 mol of oxygen in a closed container is sparked to initiate a reaction. How many grams of water can form
0.03154 mol H₂O is formed from 0.0636 g of hydrogen if we consider that O₂ is a limiting reagent.
The balanced equation is
[tex]2H_{2} (g)[/tex] + [tex]O_{2} (g)[/tex] → [tex]2H_{2} O (l)[/tex]
Here, we are calculating the moles [tex]H_{2}O (l)[/tex] from the moles of H₂ if we consider O₂ is a limiting reagent:
Given:
The mass of H₂ = 0.0636 g
We know that,
The moles of H₂ = (0.0636 g of H₂) × [tex]\frac{1.0 mol H_{2} }{2.016 g H_{2} }[/tex]
= 0.03154 mol H₂
Moles of H₂O (l) from H₂ = ( 0.03154 mol H₂) × [tex]\frac{2.0 mol of H_{2} O (l)}{2.O mol H_{2} }[/tex]
= 0.03154 mol H₂O
Therefore, 0.03154 mol H₂O is formed from 0.0636 g of hydrogen if we consider that O₂ is limiting reagent.
Learn more about limiting reagent here:
brainly.com/question/26905271
#SPJ4
Please help i dont have much time cause i have to give it in soon :,)
Balance the following neutralization reactions:
_______ HBr + _______ KOH _______KBr + _______H2O
_______ HF + _______ Fe(OH)3 _______FeF3 + ______ H2O
______HCl + _______ Ca(OH)2 _______CaCl2 + ______ H2O
Answer:
HBr + KOH = KBr + H2O
3 HF + Fe(OH)3 = FeF3 + 3 H2O
2 HCl + Ca(OH)2 = CaCl2 + 2 H2O
Explanation:
Protons Ha and Hb in the compound given are _________. homotopic enantiotopic diastereotopic mesotopic none of these
Protons Ha and Hb in the compound given are enantiotopic.
What are enantiotopic protons?Enantiotopic protons can be defined as those protons that can be replaced by another groups like deuterium.
What is a compound?A compound is a substance which contains two or more elements chemically combined together.
So therefore, Protons Ha and Hb in the compound given are enantiotopic.
Learn more about enantiotopic protons:
https://brainly.com/question/24106290
#SPJ1