Answer:
12 mmilligrams of Po-218 was the mass of the original starting material
Explanation:
The half-life of a radioactive material is the time taken for half the amount ofnthe original material present in a radioactive material to decay or disintegrate.
After each half-life, half the original material present at the start remains.
For the radioactive polonium-218 having a half-life of 3.04 minutes, it means that if 1 g is the starting material, after 3.04 minutes, 1/2 g will be remaining; after, 6.08 minutes 1/2 of 1/2 which is 1/4 of the starting material will be remaining; and after 9.12 minutes, 1/2 of 1/4 = 1/8 g will be remaining.
From the question, number of half-lives undergone after 9.12 minutes = 9.12/3.04 = 3 half-lives.
After 3 half-lives, 1/8 of the original material is remaining.
1/8 = 1.50 mg
The original mass of the sample at the start = 1.50 mg × 8 = 12 mg
Therefore, 12 milligrams of Po-218 was the mass of the original starting material.
Does the excess reactant get used up completely in a reaction??
Answer:
In a chemical reaction, reactants that are not used up when the reaction is finished are called excess reagents. The reagent that is completely used up or reacted is called the limiting reagent, because its quantity limits the amount of products formed.
Explanation:
Organize the following list of elements from highest to lowest Ionization Energy:
Phosphorus, Bismuth, Arsenic, Antimony, Nitrogen
Answer: The list of elements from highest to lowest Ionization Energy is Nitrogen > Phosphorus > Arsenic > Antimony > Bismuth.
Explanation:
The amount of energy required to remove the most loosely bound electron from an isolated gaseous atom or ion is called ionization energy.
Element with a half-filled orbital requires much more energy to remove an electron. This is because element with a half-filled electronic configuration is the most stable in nature.
More stable or tightly electrons are bound to the nucleus of an atom more will be its ionization energy. This also means that smaller is the atom higher will be its ionization energy.
When we move from top to bottom in a group the size of atom increases and the attraction between nucleus of atom and its valence electrons decreases. Hence, less will be the ionization energy.
Therefore, ionization energy decreases on moving down a group.
So, the given elements Phosphorus, Bismuth, Arsenic, Antimony, Nitrogen are all group 15 elements. Hence, decreasing order of their ionization energy is as follows.
Nitrogen > Phosphorus > Arsenic > Antimony > Bismuth
Thus, we can conclude that the list of elements from highest to lowest Ionization Energy is Nitrogen > Phosphorus > Arsenic > Antimony > Bismuth.
The total mass of reactants and products is _______ during a chemical reaction
Answer: The total mass of reactants and products is the same during a chemical reaction.
Explanation:
the total mass of reactants is equal to the total mass of products.
4. There are 1.9 moles of Oxygen gas at a pressure of 3.50 atm, and the temperature is 65°C. What is the
volume of the gas? Remember that R = 0.0821 L x atm/Kx mol AND that you must convert °C to K.
Fill in the variables chart:
Answer:
15.06 L
Explanation:
Using the ideal gas law equation:
PV = nRT
Where;
P = pressure (atm)
V = volume (L)
n = number of moles (mol)
R = gas law constant (0.0821 Latm/molK)
T = temperature (K)
According to the information provided in this question,
P = 3.50 atm
n = 1.9 moles
V = ?
T = 65°C = 65 + 273 = 338K
Using PV = nRT
V = nRT/P
V = (1.9 × 0.0821 × 338) ÷ (3.5)
V = 52.725 ÷ 3.5
V = 15.06 L
10 points. Please help.
A balloon can hold 10 liters of a gas. If you blow up this balloon with 2 moles of oxygen gas at a pressure of 0.76 atmospheres, what is the temperature of the balloon? Pay attention to the unit of pressure used.
Answer:
The temperature of the balloon is 46.34 K.
Explanation:
An ideal gas is a theoretical gas that is considered to be composed of point particles that move randomly and do not interact with each other. Gases in general are ideal when they are at high temperatures and low pressures.
An ideal gas is characterized by three state variables: absolute pressure (P), volume (V), and absolute temperature (T). The relationship between them constitutes the ideal gas law, an equation that relates the three variables if the amount of substance, number of moles n, remains constant and where R is the molar constant of the gases:
P * V = n * R * T
In this case:
P= 0.76 atmV= 10 Ln= 2 molesR= 0.082 [tex]\frac{atm*L}{mol*K}[/tex]T= ?Replacing:
0.76 atm* 10 L= 2 moles* 0.082 [tex]\frac{atm*L}{mol*K}[/tex] *T
Solving:
[tex]T=\frac{0.76 atm* 10 L}{2 moles* 0.082\frac{atm*L}{mol*K}}[/tex]
T= 46.34 K
The temperature of the balloon is 46.34 K.
It took 20.0 mL of NaOH to neutralize 25 mL of 0.50 M HCl. What is the molarity of the base?
Answer:
5/8 M
Explanation:
NaOH + HCl ====> NaCl + H2O
in 25 mL of 0.5M acid, we have 1/80 Mol of HCl
it mean we must have 1/80 Mol of NaOH.
20 mL = 1/50 L
(1/80)Mol / (1/50)L = 5/8 M
based on the graph below, which statement
Answer:
4. Atmospheric pressure decreases as altitude increases.
Explanation:
hope this helps and is right. p.s i really need brainliest :)
What is the correct name for the chemical formula N408?
Answer:
molar mass (molar weight)
Explanation:
Which of the following phase changes describes what is
happening in the following endothermic process?
H20 (1) + heat --> H2O (g)
O melting
o freezing
o boiling
O condensing
Answer:
I think the answer is boiling
90 grams of NaNO3 were added to solution at 10 degrees Celsius. What type of solution was formed?
Answer:
friend me on here and imma send you the link Explanation:
what is acid? Explain it
Answer:
An acid is a chemical that is posining or sometimes not
Explanation:
This is the best I could explain brainliest
Phenolphthalein meaning
Answer:
Phenolphthalein is a chemical compound with the formula C20H14O4 and is often written as "HIn" or "phph" in shorthand notation. Phenolphthalein is often used as an indicator in acid–base titrations. For this application, it turns colorless in acidic solutions and pink in basic solutions.
Answer:
Phenolphthalein is a chemical compound, a colorless crystalline solid, though pink in a alkaline solution, and is also used as an acid-base indicator.
Explanation:
Study the particle below carefully and answer
the questions that followed.
a)ldentify the particle.
b)Write the electronic configuration of the
particle.
c)State
i.Atomic number
ii.Mass number
iii.Proton number
iv.Electron number
d) Calculate the neutron number
e) State the valency
f)What is the valence electrons?
Answer:
b is the answer hope that helps
Balance this equation
Fe2O2 + C -> Fe + CO2
2 FeO + 1 C ===》2 Fe + 1 CO2
Explanation:
Fe2O2+C-----> 2Fe+CO2
balanced equation..
hope it helps.
stay safe healthy and happy.......3. Which model has properties most similar to chlorine?
Model A
Model B
Model C
Model D
Answer:
bnsjsbbakakaisbsbwnsjznss
Explanation:
cnsjzjsnsnsjs ssnsnsnzksmnznnzna
Which half-reaction shows conservation of charge? * 5 points A) Cu + e– → Cu+ B) Cu2+ + 2e– → Cu C) Cu+ → Cu + e– D) Cu2+ → Cu + 2e–
Answer:
B) Cu2+ + 2e– → Cu.
Explanation:
Hello there!
In this case, in the regard of redox reactions, we must keep in mind that half-reactions show us how the flow of electrons when an element undergoes a change in its oxidation state, say increasing or decreasing. In such a way, if the element is oxidized, increase the oxidation state, we add electrons on the right side and the contrary if the element is reduced, decrease the oxidation state.
In such a way, we can see that the reaction B) Cu2+ + 2e– → Cu, shows how the Cu2+ cations are reduced by adding electrons to produce Cu and thus, conserve the charge.
Best regards!
What is the percent by volume of 12.5 mL of ethanol in 250 mL of water?
3%
5%
4%
6%
The movement of water from an area of high concentration to one of low concentration through a semipermeable membrane is called ?
How many significant figures are in the measurement 1.3000 meters
Answer:
5
Explanation:
mark me brainliest!
In your OWN words, what is the difference between a solute, solvent, and solution?
Answer:A solution is a homogeneous mixture consisting of a solute dissolved into a solvent . The solute is the substance that is being dissolved, while the solvent is the dissolving medium.
Explanation:A solution is a homogeneous mixture consisting of a solute dissolved into a solvent . The solute is the substance that is being dissolved, while the solvent is the dissolving medium.
PLEASEEEEE CAN SOMEONE HELP MEEE??? (iI have TWO questions PLSPLSPLSPSLPLSPLSPLSP)
3.) What happened to Patroclus at the end of yesterday's reading?
He won the battle.
He went to Mt. Olympus to talk to Zeus.
He died.
-------------------------------------------------------------------------------------------------------
4.Who was Agamemnon trying to persuade to come fight with him again?
Patroclus
Achilles
Odysseus
Hector
6 a 100 sample of Au - 198 Au 198 be? Decays to 3.125 g in 13.5 days, what would the half-life of au198 be?
Answer:
Half-life = 2.7 days
Explanation:
The radioactive decay of an isotope follows the equation:
Ln[A] = -kt + ln[A]₀
Where [A] could be taken as the amount of A after t time, k is decay constant, [A]₀ initial amount of A.
Replacing to solve k:
Ln[3.125g] = -k*13.5days + ln[100g]
-3.465736 = -k*13.5days
k = 0.2567days⁻¹
Half-life is:
half-life = ln2 / k
Half-life = 2.7 days
cultura de Australia ?
La cultura de Australia es una cultura occidental derivada principalmente de Gran Bretaña, pero también influenciada por la geografía única del continente australiano, la diversa aportación de aborígenes, isleños del Estrecho de Torres y otros pueblos de Oceanía. ... Los australianos son generalmente relajados, abiertos y directos.
Need help ASAP ( will give 50 points)
Select the correct answer. Which galaxies have light smoothly spread across the
galaxy? A. spiral galaxy B. irregular galaxy C. lenticular galaxy D. elliptical galaxy
Answer:
Your answer would be D, Hope this helps.
Balance this chemical equation
Ca(OH)2 + HCl ---> CaCl2 + H2O
Answer:
The balance equation of Ca(OH)2 + HCl ---> CaCl2 + H2O
is
Ca(OH)2(s) + 2HCl(aq) ---> CaCl2(aq) +2H2O (l) (balanced equation)
you can test carbon dioxide gas with
Answer:
you can test carbon dioxide gas with calcium hydroxide
hope this is what you're looking for
stay safe and have a nice day
✌◕ ◡ ◕✌
please mark all that apply!
Answer:
F G there you go the guy on top is right
Explanation:
F G
Which equation correctly represents the dissociation of a strong acid in water?
Question 26 options:
CH3COOH ↔H++ CH3COO−
NaOH →Na++OH−
HCl →H+ +Cl−
NH3+ H2O↔ NH4++ OH−
The equation that correctly represents the dissociation of a strong acid in water is as follows: HCl → H+ + Cl−
What is acid dissociation?Acid dissociation is the process by which an acid breaks up into it's constituent ions in an aqueous solution.
Acids are known to contain hydrogen ions (H+), hence, dissociate into H+ and an anion.
A strong acid like HCl dissociates completely in an aqueous solution while a weak acid does not dissociate completely.
According to this question, hydrogen chloride (HCl) is said to dissociate into hydrogen ion (H+) and chloride (Cl-) according to the following expression:
HCl → H+ + Cl−
Learn more about acid dissociation at: https://brainly.com/question/4363472
#SPJ1
Tritium (hydrogen-3) has a half-life of 12.3 years. How old is a bottle of wine if the tritium content is determined to be 25% in new bottle of wine
Answer:
24.6 years
Explanation:
Applying,
A = (A')[tex]2^{a/n}[/tex]..................... Equation 1
Where A = Original Tritium content in the wine, A' = Tritium content in the wine after decay, a = age of the old bottle, n = half life of Tritium
From the question,
Let A = X, therefore, A' = 0.25X
Given: n = 12.3 years
Substitute these values into equation 1
X = 0.25X([tex]2^{a/n}[/tex])
1 = 0.25×([tex]2^{a/12.3}[/tex])
1/0.25 =
4 = [tex]2^{a/12.3}[/tex]
[tex]2^{a/12.3}[/tex] = 2²
Equation the base,
a/12.3 = 2
a = 12.3×2
a = 24.6 years
How many moles of Chromium(III) nitrate (Cr(NO3)3) are produced when Chromium reacts with 0.85 moles of Lead(IV) nitrate (Pb(NO3)4) to produce chromium(III) nitrate (Cr(NO3)3) and lead? 4 Cr + 3 Pb(NO3)4 → 4 Cr(NO3)3 + 3 Pb
Answer:
[tex]0.64molCr(NO_3)_3[/tex]
Explanation:
Hello there!
In this case, according to the given chemical equation, it turns out possible for us to realize there is a 4:3 mole ratio of chromium(III) nitrate to lead(IV) nitrate, and therefore, we can calculate the moles of the former by applying the shown below stoichiometry setup:
[tex]0.85molPb(NO_3)_4*\frac{3molCr(NO_3)_3}{4molPb(NO_3)_4} \\\\0.64molCr(NO_3)_3[/tex]
Regards!
Polar bears are adapted to stay warm by growing thick fur. These organisms most likely live in a what
Answer:
They live in the open snow
Explanation: