an unknown radioactive substance has a half-life of 3.20 hours . if 21.1 g of the substance is currently present, what mass a0 was present 8.00 hours ago?

Answer:

Because Environmental Risks

Explanation:

Medicines poured down the drain can enter the environment and your community’s drinking water supplies. And it can cause a lot of diseases!

The process of turning the raw materials gathered by mining corporations into finished goods is known as material processing.

Manufacturing is the process of converting raw materials or component components into completed products using tools, labor, machinery, and chemical processing.

The objective of material processing is to create the structural characteristics (such as crystal structure, microstructure, size, and shape) required for the product to function effectively in its intended use. Processing materials is essential to production and is at the heart of the area of materials science and engineering.

We manipulate materials to improve their strength, durability, water proofness, or even merely their aesthetic appeal. When new materials are created by combining other components, they are sometimes referred to as mixtures.

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To determine which 0.100 m solution will have the lowest vapor pressure, we need to consider the number of solute particles each substance will produce when dissolved in water. The more solute particles present, the lower the vapor pressure.

a. Sucrose: Since it is a non-electrolyte, it will not dissociate in water. Number of particles produced = 1.

b. Al(ClO₄)₃: When dissolved, it will dissociate into 1 Al³⁺ ion and 3 ClO₄⁻ ions. Number of particles produced = 1 + 3 = 4.

c. NaCl: When dissolved, it will dissociate into 1 Na⁺ ion and 1 Cl⁻ ion. Number of particles produced = 1 + 1 = 2.

d. KClO₄: When dissolved, it will dissociate into 1 K⁺ ion and 1 ClO₄⁻ ion. Number of particles produced = 1 + 1 = 2.

e. Ca(ClO₄)₂: When dissolved, it will dissociate into 1 Ca²⁺ ion and 2 ClO₄⁻ ions. Number of particles produced = 1 + 2 = 3.

The 0.100 m solution of Al(ClO₄)₃ (option b) will have the lowest vapor pressure, as it produces the highest number of solute particles (4) when dissolved in water.

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The substance in the image above would be classified as a mixture of elements (option E).

A compound is a substance formed by chemical bonding of two or more elements in definite proportions by weight.

On the other hand, a mixture is made when two or more substances are combined, but they are not combined chemically.

According to this question, an image is shown with two different substances or elements as distinguished by coloration (white and purple). These elements are combined but not chemically bonded, hence, is a mixture.

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Answer:

P₂ = 0.13880 atm

Explanation:

Given info are;

Initial volume = 13.0 L

Initial pressure = 3.15 atm

Initial temperature = 213.0 K

Final temperature = 398.0 K

Final volume = 35.0 L

Final pressure = ?

Note;

Base on general gas equation:

P₁V₁/T₁ = P₂V₂/T₂

Formula = P₁V₁/T₁ = P₂V₂/T₂  

Solution:

P₂ = P₁V₁ T₂/ T₁ V₂

P₂ = 3.15 atm x 13.0 L x 398.0k/213.0 k x 35.0 L  

P₂ = 1034.8 atm .L.K/ 7455 K.L

P₂ = 0.13880617035

P₂ = 0.13880 atm  

When we multiply or divide the values the number of significant figures must be equal to the less number of significant figures in given value.

Thus we will include five significant figures in answer because 1034.8 have five significant figure.

[RevyBreeze]

Ideal gas law is valid only for ideal gas not for vanderwaal gas. Combined Boyle's and Charles' gas law is used here. Therefore the new pressure of gas is 0.13880 atm .

Ideal gas equation is the mathematical expression that relates pressure volume and temperature.

Mathematically the relation between Pressure, volume and temperature can be given as

PV=nRT

where,

P = pressure of gas

V= volume of gas

n =number of moles of gas

T =temperature of gas

R = Gas constant = 0.0821 L.atm/K.mol

Combining Boyle's and Charles' gas law

P₁V₁/T₁ = P₂V₂/T₂

P₂ = P₁V₁ T₂/ T₁ V₂

P₂ = 3.15 atm x 13.0 L x 398.0k/213.0 k x 35.0 L  

P₂ = 1034.8 atm .L.K/ 7455 K.L

P₂ = 0.13880617035

P₂ = 0.13880 atm  

Therefore the new pressure of  gas is 0.13880 atm  when the temperature is changed to 398.0 K  and volume is increased to 35.0 liters.

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Answer:

The elements are helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), radon (Rn), and oganesson (Og).

Explanation:

We are given –

\(\qquad\)\( \pink{\bf\longrightarrow { Molar \:mass \:of \: N_2:-} }\)

\(\qquad\)\( \bf \twoheadrightarrow 14\times 2 \)

\(\qquad\)\( \bf \twoheadrightarrow 28\)

\(\qquad\)____________________

Now,Let's calculate the number of moles present in 57.1 g of \( \bf N_2\)

\(\qquad\)\( \purple{\bf\longrightarrow { No \:of \:moles = \dfrac{Given \:mass}{Molar\: mass}}}\)

\(\qquad\)\( \bf \twoheadrightarrow \dfrac{57.1}{28}\)

\(\qquad\)\( \bf \twoheadrightarrow 2.04\: moles\)

__________________________________

Answer:

increases the gravitional pull on tge pane

Answer:

generates  more lifting on the plane

Explanation:

To determine the number of moles of hydrogen needed to crack one mole of the long saturated hydrocarbon chain (C40H82), we can analyze the reactants and products involved in the cracking reaction.

The cracking reaction is given as: C40H82 -> 3 C8H18 + n C2H6. From the equation, we can see that one mole of the long hydrocarbon chain (C40H82) produces three moles of octane (C8H18) and n moles of ethane (C2H6). Since the cracking process involves breaking the carbon-carbon bonds and forming new carbon-hydrogen bonds, the number of hydrogen atoms in the products should remain the same as in the reactant.

The long hydrocarbon chain (C40H82) contains 82 hydrogen atoms, and the products, 3 moles of octane (C8H18), contain (3 moles) * (18 hydrogen atoms/mole) = 54 hydrogen atoms. Therefore, the number of moles of hydrogen needed for cracking one mole of the long hydrocarbon chain can be calculated as: Number of moles of hydrogen = 82 - 54 = 28 moles. Hence, 28 moles of hydrogen are required to crack one mole of the long saturated hydrocarbon chain (C40H82).

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Answer:

C₆H₁₂O₆ + 6O₂→6CO₂ + 6H₂O + Energy=chemical equation for cellular respiration

Explanation:

hope this help

this is james not jade

Ferns reproduce with spores which existed the longest in Earth history.

Gymnosperms reproduce with cones and has needle-like, waxy leaves.

Angiosperms reproduce with flowers and newest type of plant in Earth history.

Ferns reproduce with spores that existed the longest in Earth, gymnosperms reproduce through the formation of cones having needle-like, waxy leaves whereas angiosperms reproduce with flowers which turns into seed. The newest type of plant in Earth history is also belongs to this group.

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The element whose isotope is represented as  \(_{6}^{14}X\) is carbon -14. The atomic number of carbon is 6 and the mass number for the given isotope is 14 amu.

Isotopes are atoms of same element with different  mass numbers. Isotopes slightly changes in chemical and physical properties between each other.

Almost elements in the periodic table are having isotopes. However not all of them are stable. Some of them for heavy metals are radioactive isotopes and are not stable.

The isotope is represented by showing mass number in top of the symbol and atomic number at the bottom. The atomic number 6 corresponds to carbon. Hence, option A is correct. Carbon -14 isotope is given here.

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Answer:

\(1 \: mole = 6.02 \times {10}^{23} \: atoms \\ 6.5 \: moles = (6.5 \times {6.02 \times 10}^{23} ) \: atoms \\ = 3.913 \times {10}^{24} \: atoms\)

Explanation:

hey can I please get the passage so that I can help you

Answer:

DD

Explanation:

Answer:

22.4L

Explanation:

The mass ratio of magnesium in magnesium oxide (MgO) can be calculated by dividing the mass of magnesium (0.712 g) by the mass of magnesium oxide (1.18 g).

To find the mass ratio, we divide the mass of the element of interest (magnesium) by the mass of the compound (magnesium oxide). In this case, the mass of magnesium is given as 0.712 g and the mass of magnesium oxide is given as 1.18 g. So, the mass ratio of magnesium is calculated as follows:
Mass ratio = mass of magnesium / mass of magnesium oxide
= 0.712 g / 1.18 g
Calculating this gives us the mass ratio of 0.604.
Therefore, the mass ratio of magnesium in magnesium oxide is approximately 0.604.

The mass ratio of magnesium in magnesium oxide can be found by dividing the mass of magnesium by the mass of magnesium oxide. In this case, the mass of magnesium is given as 0.712 g and the mass of magnesium oxide is given as 1.18 g. By dividing these two values, we get a mass ratio of approximately 0.604. This means that for every gram of magnesium oxide, there are approximately 0.604 grams of magnesium. This mass ratio is useful in determining the composition of compounds and can be used in various chemical calculations.

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Of the molecules given below, the bond in HF is the most polar. Option D) is correct.

Polarity is the extent to which different atoms' electrons are shared in a chemical bond. In a molecule, the unequal distribution of charge leads to a dipole moment. The greater the electronegativity difference between the bonded atoms, the more polar the bond and molecule become.

A polar bond is created when two atoms with different electronegativity values join together. The atom with a greater electronegativity has a stronger pull on the shared electrons in the bond, resulting in a partial negative charge, while the atom with a lower electronegativity has a partial positive charge.

Fluorine is the most electronegative element on the periodic table. The electronegativity values of the elements in the bond between HF are 2.20 and 0.98 for fluorine and hydrogen, respectively. Because there is such a significant difference in electronegativity, the bond between them is highly polar.

Hence, of the molecules listed above, the bond in HF is the most polar. Hence, option D) is correct.

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Answer:

5.9 × 10² kJ

Explanation:

When carbon disulfide, CS₂, forms from its elements, heat is absorbed. The corresponding value for the standard enthalpy of formation of carbon disulfide is 117.36 kJ/mol. The thermochemical equation that represents this process is:

C(graphite) + 2 S(s, rhombic) ⇒ CS₂(g)   ΔH°f = 117.36 kJ/mol

117.36 kJ of heat are absorbed when 1 mole of CS₂ is formed. The amount of heat absorbed when 5.0 moles of CS₂ are formed is:

5.0 mol × 117.36 kJ/mol = 5.9 × 10² kJ

Answer:

B. Group 17

Explanation:

The element is Bromine. Its electron configuration is:

1s2 2s2p6 3s2p6d10 4s2p5  

You can see that its last orbital is 4p^5 for 5 electrons in the 4p orbital.

The systematic name of this molecule is 4-((2-hydroxy-3-methoxybenzyl)amino)-N-(p-tolyl)benzamide.

1. First, the molecule should be broken down into its component parts: the amide group, the amino group, the benzene ring, the tolyl group, and the hydroxy-methoxybenzyl group.

2. The amide group is composed of an acyl group (the N-(p-tolyl)acetamide part) and an amine group (the N-(2-hydroxy-3-methoxybenzyl) part).

3. The acyl group is composed of an acyl chain (the p-tolyl group) and an acid group (the acetamide group).

4. The amine group is composed of an amino group (the 2-hydroxy-3-methoxybenzyl group) and an alkyl group (the N part).

5. The benzene ring is composed of a phenyl group (the benzene ring) and a substituent (the tolyl group).

6. Using this information, the systematic name of the molecule can be constructed. The systematic name is 4-((2-hydroxy-3-methoxybenzyl

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The percent by mass composition of nitrogen:

Solution :

Total mass = Nitrogen + Oxygen

Percent mass composition of nitrogen =mass of nitrogen*2/ total mass*100

The percent by mass composition of nitrogen is 30.4.

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Answer:

2, 6, 1

Explanation:

Ag3N is dissolved into Ag and N2. Since N2 is a molecule, there should be two Ag3Ns.

The approximate atomic radius of nickel is 1.532 × 10^(-8) cm.

In a cubic unit cell, the body diagonal length (diagonal that passes through the center of the unit cell) is equal to four times the atomic radius (4r). We can use this relationship to find the atomic radius of nickel.

Given: Edge length of the unit cell (a) = 3.524 × 10^(-8) cm

The body diagonal length is given by:

Diagonal length (d) = a√3

Substituting the given values:

d = (3.524 × 10^(-8) cm) × √3

Now, we can calculate the atomic radius (r) by dividing the diagonal length by 4:

r = d / 4

Performing the calculations:

r = [(3.524 × 10^(-8) cm) × √3] / 4

r ≈ (3.524 × 10^(-8) cm) × (1.732 / 4)

r ≈ 1.532 × 10^(-8) cm

Therefore, the approximate atomic radius of nickel is 1.532 × 10^(-8) cm.

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Your lab write-up confirmed that the third mechanism, which involves an iodide ion and a persulfate ion coming together, is the rate determining step for your experiment.

If the first mechanism is correct (two iodide ions coming together), then doubling the concentration of iodide ions would increase the rate of the reaction. This is because the rate-determining step involves two iodide ions coming together, so increasing the concentration of iodide ions would increase the likelihood of this step occurring.

If the first mechanism is correct, then doubling the concentration of persulfate ions would not have any effect on the rate of the reaction. This is because the rate-determining step does not involve persulfate ions, so increasing their concentration would not affect the rate.

If the second mechanism is correct (persulfate ion decomposing), then doubling the concentration of iodide ions would not have any effect on the rate of the reaction. This is because the rate-determining step does not involve iodide ions, so increasing their concentration would not affect the rate.

If the second mechanism is correct, then doubling the concentration of persulfate ions would increase the rate of the reaction. This is because the rate-determining step involves persulfate ions decomposing, so increasing their concentration would increase the likelihood of this step occurring.

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Grams of nh3 are needed to provide the same number of molecules as in 0. 65 g of sf6 is 0.09 grams.

A mole is a very important unit of measurement that chemists use. A mole of something way you have got 602,214,076,000,000,000,000,000 of that thing, like how having a dozen eggs method you've got twelve eggs. Chemists have to degree the use of moles for very small such things as atoms, molecules, or different debris.

calculation:-

Avogadro's number A = 6.022 x 1023

Molecules of NH3 = Molecules of SF6

An x Weight of NH3 / Molecular Weight of NH3

= A x Weight of SF6 / Molecular Weight of SF6

Weight of NH3 = (Weight of SF6 / Molecular Weight of SF6) x Molecular Weight of NH3

                        = (0.75 / 146.05) x 17.03 = 0.09 grams

The weight of NH3 needed is 0.09 grams

The mole, image mol, is the unit of amount of substance within the international system of devices. the quantity of the substance is a measure of what number of elementary entities of a given substance in an item or sample. The mole is defined as containing exactly 6.02214076×10²³ basic entities

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Answer:

Net: 1N

Explanation:

1.) Net:1N, direction: left

2.) Net: 1N, direction: down

3.) Net: 0N, no motion

4.) Net: 1N, direction: up

5.) Net: 1N, direction: up

The rank of groups in order of increasing reaction rate in regards to E2 mechanism is F, Cl, Br and I.

Iodine is often non-reactive, while fluorine has an explosive reaction that makes it challenging to manage. Bromination and chlorination are typically exothermic reactions.

Group 7's halogens, which are non-metal elements, become less reactive as you move down the group. In contrast to the alkali metals in Group 1 of the periodic table, this trend is the opposite.

Halogens react at a rate of "F (2) gt Cl (2) gt Br (2) gt l (2)." Alkane react quickly with F2, but slowly with I2, necessitating the use of a catalyst. Fluorine's high electronegativity is the reason.

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Complete question: in regards to the E2 mechanism rank the leaving groups of increasing reaction rate

a) F b)I c)Br d)Cl

A) 6.19 mL of 0.268 M perchloric acid solution is required to neutralize 12.9 mL of 0.128 M calcium hydroxide solution.

B) 31.7 mL of 0.182 M potassium hydroxide solution is required to neutralize 25.4 mL of 0.228 M perchloric acid solution.

A) To solve this problem, we need to use the balanced chemical equation for the reaction between perchloric acid and calcium hydroxide, which is:

HClO₄ + Ca(OH)₂ → Ca(ClO4)₂ + 2H₂O

From the equation, we can see that one mole of perchloric acid reacts with one mole of calcium hydroxide. Therefore, we can use the following formula to calculate the volume of perchloric acid solution required:

Molarity of perchloric acid x Volume of perchloric acid solution = Molarity of calcium hydroxide x Volume of calcium hydroxide solution

Plugging in the values given in the problem, we get:

0.268 M x Volume of perchloric acid solution = 0.128 M x 12.9 mL

Solving for Volume of perchloric acid solution, we get:

Volume of perchloric acid solution = (0.128 M x 12.9 mL) / 0.268 M = 6.19 mL

B) Similar to part A, we need to use the balanced chemical equation for the reaction between potassium hydroxide and perchloric acid, which is:

KOH + HClO₄ → KClO₄ + H₂O

From the equation, we can see that one mole of potassium hydroxide reacts with one mole of perchloric acid. Therefore, we can use the following formula to calculate the volume of potassium hydroxide solution required:

Molarity of potassium hydroxide x Volume of potassium hydroxide solution = Molarity of perchloric acid x Volume of perchloric acid solution

Plugging in the values given in the problem, we get:

0.182 M x Volume of potassium hydroxide solution = 0.228 M x 25.4 mL

Solving for Volume of potassium hydroxide solution, we get:

Volume of potassium hydroxide solution = (0.228 M x 25.4 mL) / 0.182 M = 31.7 mL

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