Answer:
https://socratic.org/answers/220339
this is the answer , my grandpa create this page
Explanation:
PLEASE QUICKLY. I'll give BRAINLIEST. A sample contains 25% parent isotope and 75% daughter isotopes. If the half-life of the parent isotope is 72 years, how old is the sample?
144 years old
216 years old
288 years old
360 years old
From the calculations and the principles of radioactivity, the age of the parent isotope is 144 years
What is radioactivity?The term radioactivity has to do with the spontaneous decay of a substance.
We know that we have about 25% parent isotope still remaining hence;
[tex]0.693/t1/2 =2.303/t log No/N\\When N =0.25 No and t1/2 = 72 years\\0.693/72 =2.303/t log No/0.25No\\0.0096 = 2.303/t *0.60206\\0.0096 = 1.3865/t\\t = 1.3865/0.0096\\t =144 years[/tex]
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Answer:
A. 144 years old
Explanation:
Identify each statement below as an example of science or pseudoscience. Magnets can cure arthritis.
Answer:
pseudoscience
Explanation:
A pseudoscience may be defined as certain beliefs and statements or practices that are mistakenly regarded as a practice that is based on scientific method. These practices are claimed and thought to be factual as well as scientific, but they are incompatible with any scientific method.
One such pseudoscience is the belief that magnets can cure arthritis. It is a common belief that magnet therapy cab ease and provide a relief from the arthritis pain but scientific studies have confirmed that such treatments are ineffective for the arthritis pains and problems.
If anyone could answer this that would be great! Will mark brainliest!
Answer: I think it's 1 ATM and 0 F
Explanation:
What is the formula for percent by mass in chem
Answer:
mass percent = (mass of solute / mass of solution) x 100%
Explanation:
the tissue which continually forms new cells in plants
Answer:
Meristematic Tissues. Tissues where cells are constantly dividing are called meristems or meristematic tissues. These regions produce new cells.
Explanation:
thank me later
Thermal energy is a measure of the __________ of particles of matter. *
(subject is science I just cant change it right now)
How many formula units are there in 14.50 moles of any compound?
___X 10^___formula units
Answer:
8.73 × 10²⁴ formula units
Explanation:
To calculate the number of formula units a substance contain, we multiply the number of moles by Avagadro number (6.02 × 10²³)
number of formula units = 14.50 moles × 6.02 × 10²³
= 87.29 × 10²³
= 8.73 × 10²⁴ formula units.
A sample of unknown gas in a closed container has a temperature of 37oC and a pressure of 2 atm. What will be the pressure if the sample is heated to 127oC?
note: Put your answer up to 1 decimal and the unit, in the blank
Answer:
hdfcghbjhaiedg
Explanation:
How can I solve this pls
Explanation:
A= Mercury (ll) oxide
B= Mercury and Oxygen
This is an oxidation-reduction (redox) reaction:
2 HgII + 4 e- → 2 Hg0
(reduction)
2 O-II - 4 e- → 2 O0
(oxidation)
HgO is an oxidizing agent, HgO is a reducing agent.
The half-lives of both zero-order and second-order reactions depend on both initial concentrations and rate constants. Why does the half-life for second order decrease with increasing initial concentration
Answer:
This is because the half life of second order reactions is inversely proportional to the initial concentration of the reactant.
Explanation:
The equation to half life in the second order reactions is given by:
t1/2=1/[A]initial
From the equation, you can see that as the initial concentration of A increases the denominator also increases ,thus overall value (t1/2) decreases.
Hope this helps:)
QUICK HELP!?Where do you think all the rain that falls goes ? Be detailed and specific
Answer:
Back into the sky and sewers/drainage holes
Explanation:
Water becomes evaporated from the sun and Rain also goes into drainage holes
Into the Earth of course! Rain falls from the sky then onto the ground in the dirt making grass or flowers, or perhaps crops. Rain kan also go onto the tress in the rainforest, or maybe the beautiful Niagara Falls.
(hope this helps!)
what type of heat transfer when you get warm standing infront a fireplace,explain your reasoning
Answer:
Radiation refers to the emission of energy in rays or waves. Heat moves through space as energy waves. It is the type of heat one feels when sitting in front of a fireplace.
Explanation:
What is the molar mass of H3PO4?
(Molar mass of H = 1.0079 g/mol; P = 30.974 g/mol; O = 15.999 g/mol)
72.98 g/mol
O 78.22 g/mol
88.24 g/mol
97.99 g/mol
Answer:
Molar mass of H3PO4 = 97.99 g/mol (Approx.)
Explanation:
Find:
Molar mass of H3PO4
Given;
Molar mass of H = 1.0079 g/mol
Molar mass of P = 30.974 g/mol
Molar mass of O = 15.999 g/mol
Computation:
Molar mass of H3PO4 = (1.0079)(3) + 30.974 + 15.999(4)
Molar mass of H3PO4 = 3.0237 + 30.974 + 63.996
Molar mass of H3PO4 = 97.9937
Molar mass of H3PO4 = 97.99 g/mol (Approx.)
Answer:
The above answer is correct
Explanation:
I took the test
How many grams of NaCl are in 1.25 X 1024
molecules of Naci? Use one decimal place
Answer:
121.1g
Explanation:
First, we need to convert the number of molecules of NaCl to moles (n) by dividing by Avagadro number
That is, n = number of molecules ÷ 6.02 × 10²³
n = 1.25 X 10²⁴ ÷ 6.02 × 10²³
n = 1.25/6.02 × 10^ (24-23)
n = 0.207 × 10¹
n = 2.07moles
Using the formula; mole = mass ÷ molar mass
Molar mass of NaCl = 23 + 35.5 = 58.5g/mol
mass = molar mass × mole
mass = 58.5 × 2.07
mass = 121.1g
Describe you would obtain a sample of lead via electrolysis
Answer: Electrolysis is defined as the process by which electrolyte allows electric current to pass through it and is decomposed in the process.
Explanation:
Substances that allow the passage of electric current are known as conductors. Examples of conductors are metals, graphites. Metals are good conductors of electricity of which an example is LEAD.
Lead is a metal which can be extracted through the process of electrolysis. A substance in solution or liquid state like lead (II) bromide which allows electric current to pass through it and at the same time decompose by it is known as an ELECTROLYTE.
In the electrolysis of lead (II) bromide to obtain Lead,the electrolyte ionize into positive and negative ions. The positive ions migrate to the cathode and are known as captions. The negative ions migrate to the anode and are known as anions.
--> At the CATHODE: Pb2+ gains electrons and Lead is deposited
Pb2+(aq) + 2e -----> Pb(s)
--> At the anode: Br- gives up electrons and is liberated as bromine vapour.
2Br- (aq) ------> Br2(g) + 2e.
Which of the following represents an endothermic reaction?
Question 12 options:
A + B --> C + D + Heat
heat pack getting hot
Heat + A + B --> C + D
burning wood
Answer:
ANSWERThe second one would be one of the application of an endothermic reaction as because endothermic reaction always have the heat in the process to mix the reactants and form the products as here in a burning wood when the wood is supplied with heat then it change into products as ashes and smoke fumes So here due to the heat is involved to form the products thats the reaction is endothermic reaction.
Hope it helps
2. How many atoms of each element does a mole of Aspartame contain?
Answer:
The molecular formula for aspartame is C14H18N2O5, and its molar mass is about 294 g/mol. 1.2 g / 294 g/mol = 4.08 X 10-3 moles aspartame. Since each mole of aspartame has 2 moles of nitrogen, you have 8.16 X 10-3 moles of N in your 1.2 grams of aspartame.
Explanation:
What is the percent by volume of 12.5 mL of ethanol in 250 mL of water?
3%
5%
4%
6%
A pencil has about 2.4 grams of graphite(carbon) in it. How many atoms is this?
Answer:
2
Explanation:
Which of the following has the greatest effect on colligative properties?
A. Calcium chloride (CaCl2)
B. Aluminum Nitrate (Al(NO3)3)
C. Epsom salt (MgSO4)
D. Sodium chloride (NaCl)
A cat gets squirted with a water gun after peeing on the carpet. After a few weeks, the no longer pees on the
carpet. This is an example of...
An instinct
An individual adapting due to memories formed from experiences with stimuli
A species adapting due to a genetic mutation
An individual adapting due to a genetic mutation
Answer:
An individual adapting due to memories formed from experiences with stimuli
Explanation:
What is a limiting factor?
A limiting factor determines where an organism can live.
O A limiting factor helps an organism outcompete other organisms.
O A limiting factor helps an organism survive in a habitat.
container has 3 moles of gas with a volume of 60 liters and at a temperature of 250 K, Calculate the pressure inside the container in kPa
Answer:
103.9 KPa
Explanation:
From the ideal gas equation;
PV=nRT
From the parameters given;
P= ?
T=250 K
V= 60L
n=3
R=0.082 atmLK-1mol-1
P= nRT/V
P= 3 × 0.082 × 250/60
P= 1.025 atm
1 atm=101325 pascals
1.025 atm = 1.025 atm × 101325 pascals/1atm
= 103.9 KPa
Answer:
103.9kPa
Explanation:
To solve this question we must use the equation:
PV = nRT
P = nRT / V
Where P is pressure in atm
n are moles of the gas = 3mol
R is gas constant = 0.082atmL/molK
T is absolute temperature = 250K
V = 60L
P = 3mol*0.082atmL/molK*250K / 60L
P = 1.025atm
As 1atm = 101.325kPa
1.025atm * (101.325kPa / 1atm) = 103.9kPa
Which statement about pollination is
TRUE?
Flowers are always pollinated
by insects.
Pollen is always transferred
from the same flower
When pollination occurs.
pollen sticks to the anther.
When pollination occurs
pollen sticks to the stigma.
Answer:
D; the pollen sticks to the stigma
Explanation:
When a flower is pollinated, the pollen sticks to the stigma. However, it is not always pollinated by insects (birds and other factors can as well), pollen can be transferred from different flowers (as long as they're the same species) and pollination doesn't stick to the anther.
Answer:
d
Explanation:
because when pollution occurs than the insects move to the flower to sick nectar and then pollan giains stuck in the insect body
How does the overall charge of oxygen of -16 compare to the overall charge of oxygen -17 and oxygen -18?
Answer:
-2
The charge on an oxygen ion is -2. An oxygen atoms contain six electrons in its valence electron shell.
Explanation:
Qué volumen (en metros cúbicos) deberá tener un gas que se encuentra a 3.3 atm en un recipiente cilíndrico de radio de 2.8 m y altura 4.6 m para que la presión final sea de 1.9 atm.
Answer:
Volumen = 65.199 metro cúbico
Explanation:
Tal como lo conocemos
P1V1 = P2 V2
Aquí
P1 = 1,9 atmósferas
V1 = (pi) * r ^ 2 * h
Sustituyendo los valores dados, obtenemos
V1 = 3.14 * 2.8 * 2.8 * 4.6 = 113.241 metros cúbicos
V2 = por determinar
P2 = 3.3 atmósferas
Sustituyendo los valores dados y derivados en la fórmula principal, obtenemos -
1.9 atm * 113.241 metros cúbicos = 3.3 atm * V2
V2 = 1.9 atm * 113.241 metros cúbicos / 3.3 atm
V2 = 65.199 metro cúbico
How are people responsible for marine debris
Answer:
Marine debris comes from many different sources and enters the ocean in many ways. Intentional littering and dumping are a big cause of marine debris. ... Those rivers and streams can eventually carry the trash to the ocean. Improper or careless waste disposal is another big cause.
hope this helps
have a good day :)
Explanation:
The ratio of the mass of U-238 to the mass of Pb-206 can be used to
1.
diagnose thyroid disorders
2.
diagnose kidney function
3.
date geological formations
4.
date once-living things
Answer:3)date geological formations
Explanation:
The ratio of the mass of U-238 to the mass of Pb-206 can be used to date geological formations.
Use of radioactive elementsRadioactive elements have unstable nucleus and they can be used for dating.
Examples of radioactive elementsUranium 238Lead 206The ratio of the amounts of U 238 and Pb 206 in a rock sample enables the age of the rock to be estimated using the technique of radiometric dating.
Thus, the ratio of the mass of U-238 to the mass of Pb-206 can be used to date geological formations.
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Akosua has observed that anytime she drinks sobolo, her stool appears dark green. On one occasion
Akosua observed that her stool, which appeared dark green, turned quickly to bright red upon mixing with the perchloric acid-treated WC water.
i. What about the sobolo drink (bright red) that made the stool of Akosua green?
ii. Why did the stool of Akosua, which appeared green because she took sobolo drink, turn into
bright red upon mixing with the acidic WC water?
iii. Suggest a practical use of sobolo drink in the identification of chemicals in the science laboratory .
Answer:
i. Sobolo is a Ghanian drink that is produced from red hibiscus flower that has an average pH of 6.7
It contains cyanidin and anthocyanins, which is a red pigment that is red in an acidic medium and changes green when introduced in a basic medium that has a high pH
The pH at the rectum of the digestive system = 5 to 8 (Slightly basic)
Therefore, what made the stool of Akosua green is that the sobolo drink changes to green in basic solution
ii. The stool which appeared green because she took sobolo turn into bright red upon mixing with the acidic WC water because of the presence of anthocyanins in sobolo, it turns red in an acidic medium
iii. Sobolo which turns green, or blue in a basic medium and red in an acidic medium can be used as a litmus solution to test the pH of a given substance
Explanation:
Sobolo or soobolo in Ghana is a name for the Hibiscus tea or tisane, which is made from calyces of the hibiscus plant, and has a sour (tangy) taste and appears bright red in color
What volume of 2M NaOH is required to completely neutralize 25mL of 1M HCl?
Answer:
[tex]\boxed {\boxed {\sf 12.5 \ mL \ NaOH}}[/tex]
Explanation:
In a neutralization reaction, an acid and base react to form salt and water. The hydrogen ions (H+) and hydroxide ions (OH-) combine to form water, while the other spectator ions bond to make salt.
For this reaction, the acid is HCl (hydrochloric acid) and NaOH (sodium hydroxide).
The H (from HCl) and OH (from NaOH) combine to make water (HOH or H₂O). The other ions, Cl and Na combine to form NaCl or sodium chloride. Let's write the neutralization reaction.
[tex]HCl _{(aq)}+NaOH _{(aq)} \rightarrow NaCl _{(aq)} + H_2O _{(l)}[/tex]
Now let's perform the calculation. We should use the titration equation or:
[tex]M_AV_A= M_BV_B[/tex]
where M is the molarity of the acid or base and V is the volume.
We know there are 25 milliliters of 1 molar HCl (acid) and an unknown volume of 2 molar NaOH (base).
[tex]\bullet M_A= 1 \ M \\\bullet V_A= 25 \ mL \\\bullet M_B= 2 \ M[/tex]
Substitute the known values into the formula.
[tex]1 \ M * 25 \ mL = 2 \ M * V_B[/tex]
Since we are solving for the volume of the base, we must isolate the variabel. it is being multiplied by 2 M and the inverse of multiplication is division. Divide both sides by 2 M.
[tex]\frac { 1 \ M * 25 \ mL}{2 \ M }=\frac{2 \ M * V_B}{2 \ M}[/tex]
[tex]\frac { 1 \ M * 25 \ mL}{2 \ M }= V_B[/tex]
The units of M cancel.
[tex]\frac { 1 * 25 \ mL}{2 }=V_B[/tex]
[tex]\frac {25}{2} \ mL= V_B[/tex]
[tex]12.5 \ mL= V_B[/tex]
12.5 milliliters of 2 M sodium hydroxide are required to neutralize 25 mL of 1 M hydrochloric acid.