If a radioactive substance has a half-life of 9 days what fraction of its original mass would remain after 27 days? *

Answer:

Heat waves

Explanation:

Answer: The religious fanaticism of Aurangzeb overshadowed his virtues. His reversal of Akbar's policy of religious toleration resulted in weakening the entire structure of the Mughal empire. It led to several conflicts and wars in different parts of the country.

The energy levels of an atom is the quantized amount of energy found at different levels n = 1,2, 3 etc. Thus option B is correct.

Electrons in an atom are revolving around the nucleus through circular paths of fixed energy. These circular paths are called orbits and the different energy levels in these paths are called orbitals.

The quantized energy levels are termed as n = 1, 2, 3 that is lowest level to higher levels of energy. Electrons are able to transit between these energy levels.

Thus, a level of n=1 is the ground level or first energy level n =2 is second energy level and so on. These energy level cannot be fractions and therefore, they are said to quantised. Hence, option B is correct.

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Answer: n = 1, 2, 3,

a quantized amount of energy found at the different levels

Explanation:

Answer:

0.0835 M

Explanation:

Step 1: Write the balanced equation

NaOH + HCl ⇒ NaCl + H₂O

Step 2: Calculate the reacting moles of HCl

0.0250 L of 0.105 M HCl react.

0.0250 L × 0.105 mol/L = 2.63 × 10⁻³ mol

Step 3: Calculate the reacting moles of NaOH

The molar ratio of NaOH to HCl is 1:1. The reacting moles of NaOH are 1/1 × 2.63 × 10⁻³ mol = 2.63 × 10⁻³ mol.

Step 4: Calculate the molarity of NaOH

2.63 × 10⁻³ moles of NaOH are in 0.0315 L of solution.

M = 2.63 × 10⁻³ mol / 0.0315 L = 0.0835 M

Answer:

F4

Explanation:

Friction is a force that opposes motion

Answer:

b. 1

Explanation:

If we consider it carefully we will notice that the electronic configuration of iron III is; [Ar] 3d5 4s0.

Now, three electrons from the d orbital are paired with the three electrons from three F atoms according to the valence bond theory. This leaves out one pair of electrons localized on the d orbital of iron.

Hence the compound has one lone pair of electrons.

Answer:

This question appear incomplete

Explanation:

This question appear incomplete. However, let's answer the resulting questions. Firstly, let's define mass number since each of the "problems" refers to mass number. Mass number is the total number of protons and neutrons in the nucleus of an atom. It should also be noted that number of protons in any given neutral atom is the same with the number of electrons of such an atom.

1) Make a He atom with a mass of 4. How many protons did you put in the nucleus?

Answer: Helium (He) atom (having a mass number of 4) has an atomic number of 2. Atomic number is the number of protons and thus 2 protons would be in the nucleus of the Helium atom.

2) Make a Li atom with a mass number of 7. How many electrons did you place in the outermost orbital  (ring)?

Answer: Lithium (Li) atom (having a mass number of 7) has an atomic number of 3. Remember that atomic number (number of protons) equals number of electrons in a neutral atom. Thus, lithium atom would have 3 electrons; 2 electrons in it's first shell and 1 electron in it's outermost shell

3) Make a N atom with a mass number of 14. How many neutrons are in the nucleus?

Answer: Nitrogen (N) atom (with a mass number of 14) has an atomic number of 7. Since atomic number is the number of protons and mass number is the number of protons + neutrons. Then, number of neutrons would equal mass number minus atomic number:

number of neutrons = 14 - 7

number of neutrons = 7 neutrons

4) Make a B atom with a mass number of 11. How many electrons did you put in the second orbital (ring)?

Answer: An atom (Boron) with mass number of 11 has an atomic number of 5. Since atomic number eventually equals number of electrons, then Boron has 5 electrons; 2 electrons in it's first shell and 3 electrons in it's second orbital/ring.

Answer:

2 protons in the He nucleus,

1 electron in the outermost,

7 neutrons in the nucleus

3 electrons in the  2nd orbital ring

Explanation:

I just did it on E2020

Answer:

Volume of ammonia produced = 398.7 dm³

Explanation:

Given data:

Volume of N₂ = 200 dm³

Pressure and temperature = standard

Volume of ammonia produced = ?

Solution:

Chemical equation:

N₂ + 3H₂     →      2NH₃

Number of moles of N₂:

PV = nRT

1 atm× 200 L = n× 0.0821 atm.L/mol.K × 273 K

n = 200 atm.L /22.41 atm.L/mol

n = 8.9 mol

Now we will compare the moles of ammonia and nitrogen.

               N₂          :         NH₃

                1            :           2

              8.9          :        2/1×8.9 = 17.8 mol

Volume of ammonia:

1 mole of any gas occupy 22.4 dm³ volume

17.8 mol ×22.4 dm³/1 mol = 398.7 dm³

Answer: The empirical formula is [tex]CH_2[/tex] and molecular formula is [tex]C_4H_8[/tex]

Explanation:

We are given:

Mass of [tex]CO_2[/tex] = 18.95 g

Mass of [tex]H_2O[/tex]= 7.759 g

Molar mass of carbon dioxide = 44 g/mol

Molar mass of water = 18 g/mol

For calculating the mass of carbon:

In 44g of carbon dioxide, 12 g of carbon is contained.

So, in 18.59 g of carbon dioxide, =[tex]\frac{12}{44}\times 18.59=5.07g[/tex] of carbon will be contained.

For calculating the mass of hydrogen:

In 18g of water, 2 g of hydrogen is contained.

So, in 7.759 g of water, =[tex]\frac{2}{18}\times 7.759=0.862g[/tex] of hydrogen will be contained.

Mass of C = 5.07 g

Mass of H = 0.862 g

Step 1 : convert given masses into moles.

Moles of C =[tex] \frac{\text{ given mass of C}}{\text{ molar mass of C}}= \frac{5.07g}{12g/mole}=0.422moles[/tex]

Moles of H=[tex]\frac{\text{ given mass of H}}{\text{ molar mass of H}}= \frac{0.862g}{1g/mole}=0.862moles[/tex]

Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.

For C =[tex]\frac{0.422}{0.422}=1[/tex]

For H =[tex]\frac{0.862}{0.422}=2[/tex]

The ratio of C : H = 1: 2

Hence the empirical formula is [tex]CH_2[/tex].

The empirical weight of [tex]CH_2[/tex] = 1(12)+2(1)= 14 g.

The molecular weight = 56.1 g/mole

Now we have to calculate the molecular formula.

[tex]n=\frac{\text{Molecular weight }}{\text{Equivalent weight}}=\frac{56.1}{14}=4[/tex]

The molecular formula will be=[tex]4\times CH_2=C_4H_8[/tex]

Answer:

Milk's heavy

Explanation:

Answer:

the correct answer is A, Hg22+ on edge 2020

Explanation:

i took the review

The only cation that can form an ionic bond with an anion in the list is Hg22+.

The term "anion" refers to a negatively charged ion. An ionic bond is a kind of bond that is formed between an anion and a cation. As a result, ionic compounds are actually an ion pair.

If we look at the options closely, the only cation that can form an ionic bond with an anion in the list is Hg22+.

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Answer: I think that is C, a light sensor but im not sure

Explanation:

Answer:

temperature probe

Explanation:

Answer:

Metals

Explanation:

Answer:

To balance a reaction, the amount of reactants must be equal to the amount of products, as stated by the Law of Conservation of Matter. It may help you to keep track of  the number of each element in a list as you try to balance. It's not able to be balanced.

Answer:

2,1,1,1

Explanation:

Hope this helped!

Answer:

a. H₂S(aq) + H₂O(l) ⇄ HS⁻(aq) + H₃O⁺(aq)

b. NH₄⁺(aq) + H₂O(l) ⇄ NH₃(aq) + H₃O⁺(aq)

Explanation:

According to Bronsted-Lowry acid-base theory,

a. When dissolved in water, H₂S behaves as an acid according to the following equation.

H₂S(aq) + H₂O(l) ⇄ HS⁻(aq) + H₃O⁺(aq)

b. When dissolved in water, NH₄⁺ behaves as an acid according to the following equation.

NH₄⁺(aq) + H₂O(l) ⇄ NH₃(aq) + H₃O⁺(aq)

Answer:

Explanation:

The time spent in driving can be found by using the formula

[tex]t = \frac{d}{v} \\ [/tex]

d is the distance

v is the velocity

From the question we have

[tex]t = \frac{2952}{82} \\ [/tex]

We have the final answer as

Hope this helps you

Answer:

D) will not form any stereoisomers since the product is a saturated hydrocarbon.

Explanation:

Stereoisomerism, or spatial isomerism,refers to a type of isomerism in which  two or more molecules have the same molecular formula and atom to atom connectivity but different three-dimensional orientations of those atoms in space.

Stereoisomerism occurs in alkenes because free rotation about the C=C bond is hindered. Thus, the molecule is "locked" in a particular orientation. In a saturated alkane, there is unrestricted free rotation about the C-C bond hence straight chain alkanes do not have steroisomers.

The product formed is 3,4-dimethyl hexane which is a straight chain saturated alkane. This compound does not exhibit stereoisomerism.

Answer:

water

Explanation:

because the others are in compounds and can not be considered as  products lonely.

Answer:

29273.178 joules have been added to the gas for the entire process.

Explanation:

The specific heats of monoatomic gases, measured in joules per mol-Kelvin, are represented by the following expressions:

Isochoric (Constant volume)

[tex]c_{v} = \frac{3}{2}\cdot R_{u}[/tex] (1)

Isobaric (Constant pressure)

[tex]c_{p} = \frac{5}{2}\cdot R_{u}[/tex] (2)

Where [tex]R_{u}[/tex] is the ideal gas constant, measured in pascal-cubic meters per mol-Kelvin.

Under the assumption of ideal gas, we notice the following relationships:

1) Temperature is directly proportional to pressure.

2) Temperature is directly proportional to volume.

Now we proceed to find all required temperatures below:

(i) Alice heats the gas at constant volume until its pressure is doubled:

[tex]\frac{T_{2}}{T_{1}} = \frac{P_{2}}{P_{1}}[/tex] (3)

([tex]\frac{P_{2}}{P_{1}} = 2[/tex], [tex]T_{1} = 273.15\,K[/tex])

[tex]T_{2} = \frac{P_{2}}{P_{1}} \times T_{1}[/tex]

[tex]T_{2} = 2\times 273.15\,K[/tex]

[tex]T_{2} = 546.3\,K[/tex]

(ii) Bob further heats the gas at constant pressure until its volume is doubled:

[tex]\frac{T_{3}}{T_{2}} =\frac{V_{3}}{V_{2}}[/tex] (4)

([tex]\frac{V_{3}}{V_{2}} = 2[/tex], [tex]T_{2} = 546.3\,K[/tex])

[tex]T_{3} = \frac{V_{3}}{V_{2}}\times T_{2}[/tex]

[tex]T_{3} = 2\times 546.3\,K[/tex]

[tex]T_{3} = 1092.6\,K[/tex]

Finally, the heat added to the gas ([tex]Q[/tex]), measured in joules, for the entire process is:

[tex]Q = n\cdot [c_{v}\cdot (T_{2}-T_{1})+c_{p}\cdot (T_{3}-T_{2})][/tex] (5)

If we know that [tex]R_{u} = 8.314\,\frac{Pa\cdot m^{3}}{mol\cdot K}[/tex], [tex]n = 2\,mol[/tex], [tex]T_{1} = 273.15\,K[/tex], [tex]T_{2} = 546.3\,K[/tex] and [tex]T_{3} = 1092.6\,K[/tex], the heat added to the gas for the entire process is:

[tex]c_{v} = \frac{3}{2}\cdot \left(8.314\,\frac{Pa\cdot m^{3}}{mol\cdot K} \right)[/tex]

[tex]c_{v} = 12.471\,\frac{J}{mol\cdot K}[/tex]

[tex]c_{p} = \frac{5}{2}\cdot \left(8.314\,\frac{Pa\cdot m^{3}}{mol\cdot K} \right)[/tex]

[tex]c_{p} = 20.785\,\frac{J}{mol\cdot K}[/tex]

[tex]Q = (2\,mol)\cdot \left[\left(12.471\,\frac{J}{mol\cdot K} \right)\cdot (536.3\,K-273.15\,K)+\left(20.785\,\frac{J}{mol\cdot K} \right)\cdot (1092.6\,K-546.3\,K )\right][/tex]

[tex]Q = 29273.178\,J[/tex]

29273.178 joules have been added to the gas for the entire process.

Answer:

Both molarity and formality express concentration as moles of solute per liter of solution. Formality is a substance's total concentration in solution without regard to its specific chemical form. ... The formality of a solution is defined as the number of formula mass of any solute dissolved in 1 litre of solution.

Answer:

M = 0.23 M

Explanation:

Given data:

Molarity of solution = ?

Mass of NH₄Br = 4.50 g

Volume of solution = 213 mL (213 mL× 1L /1000 mL = 0.213 L)

Solution:

Molarity is used to describe the concentration of solution. It tells how many moles are dissolve in per litter of solution.

Formula:

Molarity = number of moles of solute / L of solution

Number of moles of NH₄Br:

Number of moles = mass/molar mass

Number of moles = 4.50 g / 97.94 g/mol

Number of moles = 0.05 mol

Molarity:

M = 0.05 mol/ 0.213 L

M = 0.23 M

Answer: The resulting isotope is [tex]^{231}_{92}\textrm {U}[/tex]

Explanation:

Alpha Decay: In this process, a heavier nuclei decays into lighter nuclei by releasing alpha particle. The mass number is reduced by 4 units and atomic number is reduced by 2 units.

[tex]^{235}_{92}\textrm{U} \rightarrow ^{231}_{90}\textrm {Th}+^{4}_{2}n[/tex]

Beta Decay : It is a type of decay process, in which a proton gets converted to neutron and an electron. This is also known as -decay. In this the mass number remains same but the atomic number is increased by 1.

[tex]^{231}_{90}\textrm{Th}\rightarrow ^{231}_{92}\textrm {Th}+2^{0}_{-1}n[/tex]

The resulting isotope is [tex]^{231}_{92}\textrm {U}[/tex]

Explanation:

[tex]answer[/tex]

The overall cell potential can be calculated by using the equation E0cell=E0red−E0oxid. Step 2: Solve. Before adding the two reactions together, the number of electrons lost in the oxidation must equal the number of electrons gained in the reduction. The silver half-cell reaction must be multiplied by two.

The appetite effect cause one to believe is those who witness violence in the media see the world as threatening.

The appetite effect is used as a slang here, if someone is consuming violent media.

If someone is consuming violent media, then his appetite effect will be threatening from the world.

Thus, the correct option is B. Those who witness violence in the media see the world as threatening.

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Answer:

b

Explanation:

edge 2022

Answer:

yes I would

Explanation:

but I would like to advice you to add more info about project and be precise

Answer:

CaO, CaF2, or CaCl2

Explanation:

In an ionic compound, the charges need to balance out. This is the only set of compounds that fits this criteria.

Answer:

CaO CaF2 CaCl2 are ionic

Explanation:

Because electronegativity difference between calcium and other atom is more than 1.7

Answer: 1.95 g of oxygen is present.

Explanation:

According to Dalton's law, the total pressure is the sum of individual pressures.

[tex]p_{total}=p_{methane}+p_{oxygen}[/tex]

Given : [tex]p_{total}[/tex] =total pressure of gases = 727 mm Hg

[tex]p_{methane}[/tex] = partial pressure of methane = 571 mm Hg

[tex]p_{oxygen}[/tex] = partial pressure of oxygen = ?

[tex]727=571+p_{oxygen}[/tex]  

[tex]p_{oxygen}=156mmHg[/tex]

Also [tex]p_{oxygen}=x_{oxygen}\times p_{total}[/tex]

Given : 3.62 g of methane is present

moles of methane = [tex]\frac{\text{Given mass}}{\text {Molar mass}}=\frac{3.62g}{16g/mol}=0.226moles[/tex]

[tex]x_{oxygen}[/tex] = mole fraction of oxygen  

=[tex]\frac{\text {moles of oxygen}}{\text {total moles}}=\frac{y}{y+0.226}[/tex]

[tex]156=\frac{y}{y+0.226}\times 727[/tex]

[tex]y=0.061[/tex]

mass of oxygen = [tex]moles\times {\text {Molar mass}}=0.061\times 32=1.95g[/tex]

Thus 1.95 g of oxygen is present.

To determine the mass of CO₂, the following must be known :

Reaction

Decomposition of CaCO₃

CaCO₃ ⇒ CaO + CO₂

Given the mass of  CaCO₃, so to determine the mass of CO₂ :

1. Find the mol of  CaCO₃ from the molar mass of  CaCO₃

[tex]\tt n_{CaCO_3}=\dfrac{mass~CaCO_3}{MW~CaCO_3}[/tex]

2. Find the mole ratio of  CaCO₃ : CO₂(from equation = 1 : 1)

[tex]\tt n_{CaCO_3}\div n_{CO_2}=1\div 1[/tex]

3. Find the mass of CO₂ from the molar mass of CO₂

[tex]\tt mass_{CO_2}=n_{CO_2}\times MW_{CO_2}[/tex]

Answer:

1 3 and 5

Explanation: