If the half life of iridium-182 is 15 years, how much of a 3 gram sample is left after 2 half-lives?
A) .57 grams
B) .70 grams
C) 2.25 grams
D) .75 grams

Answers

Answer 1

Answer:

D. 0.75 grams

Explanation:

The data given on the iridium 182 are;

The half life of the iridium 182, [tex]t_{(1/2)}[/tex] = 15 years

The mass of the sample of iridium, N₀ = 3 grams

The amount left, N(t) after two half lives is given as follows;

[tex]N(t) = N_0 \left (\dfrac{1}{2} \right )^{\dfrac{t}{t_{1/2}} }[/tex]

For two half lives, t = 2 × [tex]t_{(1/2)}[/tex]

∴ t = 2 × 15 = 30

[tex]\dfrac{t}{t_{(1/2)}} = \dfrac{30}{15} = 2[/tex]

[tex]\therefore N(t) = 3 \times\left (\dfrac{1}{2} \right )^2 = 0.75[/tex]

∴ The amount left, N(t) = 0.75 grams


Related Questions

Question
Calculate the total energy, in kilojoules, that is needed to turn a 35 g block
of ice at -10 degrees C into water vapor at 100 degrees C.

Answers

Answer:

34545 J

Explanation:

Applying,

E = mc'+cm(t₂-t₁)+Cm(t₂-t₀).............. Equation 1

Where E = Total energy, m = mass of the ice, c' = latent heat of ice, c = specific heat capacity of ice, t₂ = final temperature, t₁ = initial temperature, C = specific heat capacity of water, t₀ = temperature of ice at 0°C

From the question,

Given: m = 35 g = 0.035 kg, t₁ = -10°C, t₂ = 100°C, t₀ = 0°C

Constant: C = 4200 J/kg.K, c = 2100 J/kg.K, c' = 336000 J/kg

Susbtitute these values into equation 1

E = [336000(0.035)]+[0.035×2100(100+10)]+[4200×0.035(100-0)]

E = 11760+8085+14700

E = 34545 J

Plz help it’s due very soon

Answers

Answer:

192g

Explanation:

so for this find out there moles of CH4 by moles=mass/mr

48/16=3 then use molar ratio 1:2 so times it by 2 which is 6 moles. then uses mass =moles*mr so 6*32=192g is the answer hope this helps to understand.

Answer:

64

Explanation:

How many atoms are there in total in a molecule of sulfur trioxide SO3??​

Answers

Answer:

I got 1.14 mol So3 as the answer

hopefully if this could help

2. When we lift a stool, its ____________
A) gravitational potential energy is increased
B) gravitational potential energy is decreased
C) kinetic energy is decreased
D) gravitational potential energy remains unchanged

Answers

A.)

Standing on an elevated ledge would be more potential energy than standing on the ground. Same applies for anything else -- Including a chair!


Ethanol has a heat capacity of 2.46 Jig 'c. If 50 g of ethanol has a temperature of 30°C and a piece of hot Copper is added to the ethanol causing the
temperature to increase to 70°C. What is the amount of heat absorbed by the ethanol?

Answers

Explanation:

there it is fella tried on ma own consciousness

A certain element has two naturally occurring isotopes. The atomic mass of isotope 1 (35.4723 % natural abundance) is 184.9529 amu. Determine the atomic mass of isotope 2. The average atomic mass of the element is 186.2071 amu. Do not include units; report answer to 4 decimal places.

Answers

Answer:

the value

Explanation:

The part of an atom that has an overall positive charge is called
A)
an electron
B)
the nucleus
C)
the first shell
D)
the valence shell

Answers

Answer: I think it’s B


[tex]what \: is \: acid \: \: \: {?} [/tex]

Answers

meaning:An acid is a chemical substance, usually a liquid, which contains hydrogen and can react with other substances to form salts. Some acids burn or dissolve other substances that they come into contact with.

Answer:

Hope it help you#CarryOnLearning

three functions of the stem​

Answers

The three functions of the stem:

To support the leaves,To conduct water, and To conduct minerals to the leaves.
1.Stems support the plant body

2. Stems transport materials between the root system, the leaves and the reproductive structures

3.Stems hold up reproductive structures, like flowers, which helps pollinators, such as bees, find the flowers.

Se realiza una mezcla de minerales de Cu y Fe: 20 kg FeS2 (pirita), 70 kg de Fe2O3 (hemetita) 15 kg de CuFe2 (calcopirita) y 90 kg de CuO (tenorita). Calcule: Porcentaje de hierro Porcentaje de cu Porcentaje de azufre y oxigeno

Answers

Answer:

34.78% Fe

39.66% Cu

5.48% S

20.07% O

Explanation:

Para resolver esta pregunta debemos hallar la masa de cada átomo en cada mineral. Así, podremos hallar el porcentaje de cada átomo:

Pirita (Fe: 55.845g/mol; S: 32.065g/mol; FeS2: 119.975g/mol)

Masa Fe:

20kg FeS2 * (1*55.845g/mol / 119.975g/mol) = 9.31kg Fe

Masa S:

20kg FeS2 * (2*32.065g/mol / 119.975g/mol) = 10.69kg S

Hemetita (Fe: 55.845g/mol; O: 16g/mol; Fe2O3: 159.688g/mol)

Masa Fe:

70kg Fe2O3 * (2*55.845g/mol / 159.688g/mol) = 48.96kg Fe

Masa O:

70kg Fe2O3 * (3*16g/mol / 159.688g/mol) = 21.04kg O

Calcopirita (Fe: 55.845g/mol; Cu: 63.546g/mol; CuFe2: 175.236 g/mol)

Masa Fe:

15kg CuFe2 * (2*55.845g/mol / 175.236 g/mol) = 9.56kg Fe

Masa Cu:

15kg CuFe2 * (1*63.546g/mol / 175.236 g/mol) = 5.44kg Cu

Tenorita (O: 16g/mol; Cu: 63.546g/mol; CuO: 79.545 g/mol)

Masa O:

90kg CuO * (1*16g/mol / 79.545 g/mol) = 18.10kg O

Masa Cu:

90kg CuO * (1*63.546g/mol / 79.545 g/mol) = 71.90kg Cu

Masa Total: 20kg + 70kg + 15kg + 90kg = 195kg

Porcentaje Hierro:

9.31kg Fe + 48.96kg Fe + 9.56kg Fe / 195kg * 100 =

34.78% Fe

Porcentaje Cobre:

5.44kg Cu + 71.90kg Cu / 195kg * 100 =

39.66% Cu

Porcentaje Azufre:

10.69kg S / 195kg * 100 =

5.48% S

Porcentaje Oxígeno:

21.04kg O + 18.10kg O/ 195kg * 100 =

20.07% O

another name for constant boiling mixture​

Answers

Answer:

Azeotrope

Explanation:

An azeotrope is a liquid mixture that has a constant boiling point and whose vapor has the same composition as the liquid

Another name for constant boiling mixture.

[tex]\sf\purple{Azeotrope.}[/tex] ✅

An azeotrope or a constant boiling point mixture is a mixture that has the same composition in liquid and vapour phase.

[tex]\large\mathfrak{{\pmb{\underline{\orange{Happy\:learning }}{\orange{!}}}}}[/tex]

How much mass does 1 mol of O2 gas have?
O A. 16.00 x 2g
O B. 16.00 x (6.02 x 10^23) g
C. 2 x (6.02 x 10^23) g
D. 16.00 g

Answers

Answer:

Option A.

Explanation:

1 mol of anything contains 6.02×10²³ particles.

We know that 1 mol of oxygen gas contains 2 moles of O.

1 mol of oxygen weighs 16 g/mol, the mass for 1 molecule of O.

By the way, the mass for 1 mol of O₂ may be:

Option A  →  16 g/mol . 2 mol

32 g

Oyxgen is a dyatomic molecule, that's why we have 2 moles of O.

Another example can be:

1 mol of water (H₂O) contains 2 moles of H and 1 mol of O.

What is the gram molecular mass of a compound if 5 moles of the compouns has a mass of 100 grams?

Answers

Answer:

20 grams.

Explanation:

5 mols of a compound has a mass of 100 grams

1 mol of the same compound has a mass of 100/5 = 20 grams

hyy guys.... can you plz writ me a journal plz ..... connection with science... any topic will be done today is my submition​

Answers

ur best try is to copy and paste and change some words.

what form of the ideal gas law would you use to calculate the volume of gas

Answers

Answer:

V = nRT/P

Explanation:

The ideal gas law states that

PV=nRT

where P = pressure, V = volume, n = number of moles, R = ideal gas constant, and T= temperature

P V = n R T

to get V on its own, divide both sides of the equation by P

V = (nRT)/P

¿Cual es la sustancia que puede causar la muerte? (Estoy poniendo cualquier cosa para registrarme) 3

Answers

Answer:

Veneno.

Explicación:

El veneno es la sustancia que puede causar la muerte porque el veneno destruye las células que entran en contacto con el veneno. Si el veneno causa menos daño por lo que no ocurre la muerte del paciente mientras que por otro lado, si el veneno entra en contacto con los órganos vitales y causa más destrucción, el paciente eventualmente morirá, por lo que podemos decir que las sustancias tóxicas y venenosas causan daño y muerte. de la gente.

Calculate the molarity of the following solution: 1.0 mole of KCl in .75 L of solution.
1.3 M
2.0 M
0.750 M
99 M

Answers

Answer:

1.3 M

Explanation:

1 mole= Concentration * Volume

1 mole=C*0.75 L

C=1.3 M

which of these elements has two valence electrons?

a. hydrogen (H)
b. barium (Ba)
c. nitrogen (N)
d. krypton (Kr)
e. bromine (Br)​

Answers

Hydrogen only has 1 electron so not A.
Barium has 2 valence electrons so answers B!

The
volume
occupied by 5.0g in neon
03368 atm and
a temperatureof
35°C will be?​

Answers

Answer:

uryehrufurudududjehshsyshzyyxzhsu

Use the periodic table to determine the amount of copper and aluminum nitrate formed in the reaction.

Type the correct answer in the box. Express your answer to the correct number of significant figures.

In the reaction,
moles of Cu and
moles of Al(NO3)3 are formed.

Answers

Answer:

23, 51

Explanation:

Edmentum/plato

As per the balanced reaction, 2 moles of aluminum metal and 3 moles of copper nitrate gives 2 moles of aluminum nitrate and 3 moles of copper metal.  10 g  of Al and 25g of copper nitrate gives 0.08 moles of aluminum nitrate and 0.13 moles of copper.

What is limiting reactant ?

A limiting reactant is the reacting species which is not sufficient in amount to complete the reaction. Hence, the limiting reactant determines the yield of the reaction.

The given reaction is written as:

[tex]\rm 3Cu(NO_{3})_{2} + 2Al \rightarrow 2 Al(NO_{3})_{3} + 3Cu[/tex]

2 moles of Al and 3 moles of copper nitrate gives 2 moles of aluminum nitrate and 3 moles of Cu.

Molar mass of copper nitrate = 187.5 g/mol

atomic mass of aluminum = 27 g/mol

then, number of moles in 10 g of Al = 10 g/27 g/mol = 0.37 moles.

number of moles in 25 g of copper nitrate = 25 g/187.5 g/mol = 0.13 moles.

0.37 moles of Al needs 0.5 moles of copper nitrate to react with. Hence, copper nitrate is the limiting reactant.

3 moles of copper nitrate gives 2 moles of aluminum nitrate. Then 0.13 moles will give 2/3rd of 0.13 i e., 0.08 moles of aluminum nitrate. Similarly 0.13 moles copper nitrate gives 0.13 moles of copper metal.

Find more on limiting reactant:

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Your question is incomplete. But your complete question probably was:

10 g of aluminum metal reacts with 25 g of copper nitrate. Use the periodic table to determine the amount of copper and aluminum nitrate formed in the reaction.

In the reaction,

moles of Cu and

moles of Al(NO3)3 are formed.

What is the two major types of chemical bonding?

Answers

Answer:

Ionic bond and covalent bond

Explanation:

The two main types of chemical bonding are ionic bond and covalent bond.

In an ionic bond, there is a transfer of electrons from one atom to another. Usually from a metal to a nonmetal leading to the existence of an ion pair. Ionic compounds are soluble in water and have high melting and boiling points due to the strong electrostatic interaction between ions in the compound.

A covalent bond involves sharing of electrons between atoms. In an ordinary covalent bond, the shared electrons are furnished by the two bonding atoms while in a dative covalent bond, the two bonding electrons are furnished by only one of the bonding species.

PLEASE ANSWER! WILL GIVE A LOT OF POINTS! NEEDS EXPLANATION! NO LINKS OR I'LL REPORT!! PLEASE

distilling ethanol from a wine to determine the percentage of alcohol in a wine uses what type of property

physical property
bonding property
homeowner's property​

Answers

Answer:

Bonding property

Explanation:

Distillation deals with boiling solutions. Therefore the boiling point has a major part to play. Boiling point of a substance deals with the type of bonds present. For example water has hydrogen bonding which is a weak intermolecular force therefore the boiling point of water isn't that high. If we were to focus on an ionic compounds the boiling point would be higher because ionic compounds have ionic bonding which are stronger bonds which therefore requires more energy to break those bonds therefore a higher boiling point.

In this case for the ethanol to distill the property it's focusses on is the bonds. The strength of the bonds really.

The compounds that form from the bonding of the hydroxyl group (-OH) to a hydrocarbon are called the aldehydes.
True
False

Answers

i think its true, not 100% sure tho

Answer:

False.

I just got it right, lol.

What is the molarity of a solution of 58.7 grams of MgCl2 in 359 ml of solution?

Answers

Answer:

1.72 M

Explanation:

Molarity is the molar concentration of a solution. It can be calculated using the formula a follows:

Molarity = number of moles (n? ÷ volume (V)

According to the information provided in this question, the solution has 58.7 grams of MgCl2 in 359 ml of solution.

Using mole = mass/molar mass

Molar mass of MgCl2 = 24 + 35.5(2)

= 24 + 71

= 95g/mol

mole = 58.7g ÷ 95g/mol

mole = 0.618mol

Volume of solution = 359ml = 359/1000 = 0.359L

Molarity = 0.618mol ÷ 0.359L

Molarity = 1.72 M

What type of molecule is shown below?

A. Ether
B. Alcohol
C. Aldehyde
D. Ketone

Answers

The answer is choice C. Adlehyde

The given molecule is an aldehyde with the formula HCHO. It is the simplest and primary aldehyde . Hence, option c is correct.

What are aldehydes ?

Aldehydes are a class of organic compounds that contain a carbonyl group (a carbon double-bonded to an oxygen) at the end of a carbon chain. The general formula for an aldehyde is RCHO, where R is a substituent or side chain attached to the carbonyl group.

Aldehydes are often characterized by their distinctive odor, which can be described as pungent and irritating. Some common aldehydes include formaldehyde (used in building materials and as a disinfectant), acetaldehyde (found in alcoholic beverages), and benzaldehyde (used in food flavorings).

Aldehydes are important intermediates in many chemical reactions, and they are used in a variety of industrial and laboratory applications. They can be synthesized by the oxidation of primary alcohols or by the partial oxidation of hydrocarbons. The given compound is formaldehyde HCHO.

Find more on aldehydes:

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How many silicons atoms are there in 0.0356 moles of silicon

Answers

Answer:

2.14 × 10²² atoms Si

General Formulas and Concepts:

Atomic Structure

Reading a Periodic TableMoles

Stoichiometry

Using Dimensional Analysis

Explanation:

Step 1: Define

Identify

[Given] 0.0356 mol Si

[Solve] atoms Si

Step 2: Identify Conversions

Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.

Step 3: Convert

[DA] Set up:                                                                                                       [tex]\dipslaystyle 0.0356 \ mol \ Si(\frac{6.022 \cdot 10^{23} \ atoms \ Si}{1 \ mol \ Si})[/tex][DA] Multiply [Cancel out units]:                                                                        [tex]\dipslaystyle 2.14383 \cdot 10^{22} \ atoms \ Si[/tex]

Step 4: Check

Follow sig fig rules and round. We are given 3 sig figs.

2.14383 × 10²² atoms Si ≈ 2.14 × 10²² atoms Si

Write the electron configuration for Gold (Au). You may choose to write it in the long form or in the noble gas configuration form (shortcut).

Answers

Answer:

1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s²4d¹⁰5p⁶6s¹4f¹⁴5d¹⁰

Explanation:

how many moles are in 150 grams of water​

Answers

Answer:

Solution given:

H20=1+1+16=18grams

we have

1 mole of water =18grams

now

150grams of water=1/18*150=25/3 =8.33mole.

150 grams of water =8.33mole.

Note:

mole =given mass/actual mass of molecule/atom

1 mole of water is 18 grams.

Then,

150 grams of water,

→ 1/18 × 150

→ 25/3

→ 8.33333 . . .

Hence, 150 grams of water is 8.3 moles.

Calculate the pressure kPa of 0.421 mole of helium gas at 254 degree celsius when it occupies a volume of 3.32 L.

Answers

I didn’t understand the question ♥️

Need the answer ASAP!!!

Select the correct answer.
A student puts a glass of water in the freezer. Later, he notices ice forming on the surface of the water. Which property of water best explains
why ice forms on its surface?
OA
Ice has more surface tension than liquid water,
OB.
Ice is less dense than liquid water.
OC.
Ice has a lower freezing point than liquid water.
OD
Ice is more cohesive than liquid water.
O E.
Ice can dissolve more oxygen than liquid water.

Answers

Answer:

The Ice is Less Dense than the Water

Explanation:

I just answered this one myself, and the explanation is also just that Ice isn't dense enough to sink.

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