Really stuck on this question !! Pls help

Answer:

The half life for radioactive can be calculated as:

N /N0 = (1 /2) ^ n

n = T /T half

According to question there are n number of half life are present which would result in remaining amount of element as n.

Explanation:

Sorry if wrong

Answer:

1. atom

2. 0.5n

Explanation:

Because half of the atom's nuclei will decay during each cycle.

Answer:

P₄ + 6 H₂ ⇒ 4 PH₃

Explanation:

Let's consider the unbalanced reaction that takes place when phosphorus reacts with hydrogen to form phosphine. This is a synthesis reaction.

P₄ + H₂ ⇒ PH₃

We will balance this reaction using the trial and error method. First, we will balance P atoms by multiplying PH₃ by 4.

P₄ + H₂ ⇒ 4 PH₃

Finally, we get the balanced equation by multiplying H₂ by 6.

P₄ + 6 H₂ ⇒ 4 PH₃

Answer:

A. It secretes hormones that regulate blood sugar levels.

Explanation:

The pancreas is the organ that helps in the process of digestion of the food. The location of the pancreas is in the abdomen. It helps in the process of digestion of the food and regulating the blood sugar level in the body. It helps in regulating and controlling the glucose level in the body during the process of digestion. Pancreas produces enzymes that are useful in the process of digestion.

Answer:

A

Explanation:

Explanation:

Description. Regardless of the type of hydrocarbon, combustion with oxygen produces 3 products: carbon dioxide, water and heat, as shown in the general reaction below.

Answer:

[tex]P_2=16atm[/tex]

Explanation:

Hello there!

In this case, according to the given information, we can infer we need to use the Gay-Lussac's equation it order to understand this pressure-temperature relationship as shown below:

[tex]\frac{P_1}{V_1}=\frac{P_2}{V_2}[/tex]

Thus, we solve for P2 and plug in P1, T1 and T2, to obtain:

[tex]P_2=\frac{P_1T_2}{T_1}\\\\P_2=\frac{8atm*600K}{300K}\\\\P_2=16atm[/tex]

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Answer:

moles =60.05/12

moles=5.0041

moles=5(approx)

Answer:What is the volume of 37% HCl?

If however you meant to say 0.025M and assuming you want to prepare 1L solution then the volume of 37% HCl needed should be= (1000 X 0.025X 36.5)/ (37X1.19X10)=2.07 mL diluted to 1 L using DI water. Good day. If you want 0.025 mole HCl solution, you should take a 2.09 ml of your acid.

Explanation:To prepare 5% solution from this acid; simply take 5 ml. of the acid and add it to 95 ml of distilled water.You get a 5%HCl solution. By the way, Hydrogen Chloride is the name designated to the gas evolved from HCl acid

To determine the volume of a 5% solution that can be made from 25 mL of HCl, we need to use the equation: C1V1 = C2V2

Where:

C1 = Initial concentration of HCl

V1 = Initial volume of HCl

C2 = Final concentration of the solution (5% or 0.05 in decimal form)

V2 = Final volume of the solution (unknown)

HCl stands for hydrochloric acid. It is a strong, highly corrosive acid that is commonly used in various industrial, laboratory, and chemical applications. In its pure form, hydrochloric acid is a colorless liquid with a pungent odor. It is composed of hydrogen (H) and chlorine (Cl) and is known for its acidic properties.

Let's plug in the known values:

C1 = 100% (since the initial HCl is undiluted)

V1 = 25 mL

C2 = 5% or 0.05

V2 = Unknown

Solving for V2:

C1V1 = C2V2

(1)(25 mL) = (0.05)(V2)

25 mL = 0.05V2

Divide both sides by 0.05 to isolate V2:

V2 = 25 mL / 0.05

V2 = 500 mL

Therefore, from 25 mL of HCl, you can make a 500 mL solution with a concentration of 5%.

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Answer:

0.20 moles of Pb(CH3COO)4

Explanation:

89g Pb(CH3COO)4 x 1 mol Pb(CH3COO)4 / 443.376 g Pb(CH3COO)4

= 0.20 moles of Pb(CH3COO)4

One mole of lead acetate weighs 443.29 g. Then, 89 grams of lead acetate contains 0.20 moles of Pb (CH₃COO)₄.

One mole of a substance is its amount containing 6.02 × 10²³  atoms or molecules. This number is called Avogadro number. One mole of every elements contains Avogadro number of atoms.

Similarly one mole of every compound contains 6.02 × 10²³  molecules. The mass of one mole of compound is called its molar mass. The number  of moles of the compound can be determined by dividing the given mass by molar mass.

Molar mass of lead acetate = 443.29 g/mol

given mass  = 89 grams

then , no.of moles = weight/molar mass

n = 89 g/ (443.29 g/mol) = 0.20 moles

Therefore, the number of moles of Pb (CH₃COO)₄ in 89 g is 0.20 moles.

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Answer:

7.05 × 10⁻²² nm

Explanation:

Step 1: Given and required data

Step 2: Calculate the wavelength (λ) of the light evolved

We will use Planck-Einstein's relation.

E = h × c/λ

λ = h × c/E

λ = (6.63 × 10⁻³⁴ J.s) × (3.00 × 10⁸ m/s)/(282 × 10³ J) = 7.05 × 10⁻³¹ m

We will convert λ to nm using the conversion factor 1 m = 10⁹ nm.

7.05 × 10⁻³¹ m × 10⁹ nm/1 m = 7.05 × 10⁻²² nm

Answer:

Assuming that all of the oxygen is used up, 1.53×4111.53×411 or 0.556 moles of C2H3Br3 are required. Because there are only 0.286 moles of C2H3Br3 available, C2H3Br3 is the limiting reagent.

Limiting Reagent What is the limiting reagent if 76.4 grams of C2H3Br3 were reacted with 49.1 grams of O2? C2H3Br3 + 11O2 → 8CO2 + 6H2O + 6Br2 SOLUTION Using Approach 1: A. 76.4g × (1 mol/ 266.72 g) = 0.286 moles C2H3Br3 49.1g × (1 mole/ 32 g) = 1.53 moles O2 B.

Explanation:

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https://chem.libretexts.org/Bookshelves/Introductory_Chemistry/Map%3A_Introductory_Chemistry_(Tro)/08%3A_Quantities_in_Chemical_Reactions/8.04%3A_Limiting_Reactant_and_Theoretical_Yield

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Answer:

The first group to contain a non-metal is Group 18.

Answer:

Explanation:

The net force on electron is electrostatic force between electron and proton in the nucleus .

Fc = [tex]\frac{1}{4\pi\epsilon} \times \frac{e\times e}{r^2}[/tex]

This provides the centripetal force for the circular path of electron around the nucleus .

Centripetal force required = [tex]\frac{m\times v^2}{r}[/tex]

So

[tex]\frac{m\times v^2}{r}=\frac{1}{4\pi\epsilon} \times \frac{e\times e}{r^2}[/tex]

[tex]v^2=\frac{e^2}{4\pi \epsilon m r}[/tex]

[tex]v=(\frac{e^2}{4\pi \epsilon m r})^{\frac{1}{2} }[/tex]

Answer:

When the temperature and the amount of gas decrease, the pressure decreases.

Explanation:

At the base of the mountain, the temperature is 20 °C (293 K) and as she climbs, the temperature on the summit decreases to -15 °C (258 K). We can see the effect of the temperature on the pressure using Gay-Lussac's law.

P/T = k

P = k × T

As we can see, there is a direct relationship between P and T. So, when the temperature decreases, the kinetic energy of the gas does as well, and consequently, the pressure decreases.

Also, as the mountaineer consumes oxygen, the number of moles (n) of oxygen decreases. We can appreciate the effect on the pressure using the gas ideal equation.

P × V = n × R × T

P = n × R × T / V

There is also a direct relationship between n and P. When the amount of gas decreases, so does the pressure.

Strata are the layers of rock or soil that are distinguishable from other layers that have been laid down upon one another over the history of the earth.

A strata is the horizontal layer of rocks or sedimentary rocks that are laid upon another or arranged one on top of another that is separated by adjacent beds planes or layers.

Therefore, Strata are the layers of rock or soil that are distinguishable from other layers that have beenlaid down upon one another over the history of the earth.

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Answer:

A

Explanation:

edge21

Answer:

We often want to decrease the rates of certain reactions rather than speeding them up. For example, to prolong the shelf lives of certain foods, the chemical reactions by which they spoil must be slowed down.

Answer:

A) Chocolate Milk

Explanation:

A homogeneous mixture is one that is made of one substance. Technically, none of these are, but chocolate milk would be the closest. Pizza has cheese, pepperoni, and crust. Chocolate chip cookies have chips and the cookie. Peanut butter sandwiches have peanut butter and bread. Therefore, chocolate milk is right, as it has no other parts.

Answer: I believe the answer is A. The order of amino acids in the protein.

Explanation:

Answer:

potassium carbonate

Explanation:

Let us consider the equilibrium for the dissociation of copper I carbonate;

Cu2CO3(s)------>2Cu^+(aq) + CO3^2-(aq)

Now we need to add a substance that has a common ion with the solute. The addition of this substance will decrease the solubility of the solute thereby increasing the concentration of the promote the precipitation of copper(I) carbonate precipitate in the system.

Hence, addition of potassium carbonate  promotes the precipitation of copper(I) carbonate.

Explanation:

Cu + 2 AgNO3 → Cu(NO3)2 + 2 Ag

Cu is oxidized

Ag+ is reduced

Cu is the reducing agent

To solve such this we must know the concept of displacement reaction. The balanced reaction of silver nitrate with copper is of  displacement type of reaction.

AgNO[tex]_3[/tex] + Cu [tex]\rightarrow[/tex] Cu(NO[tex]_3[/tex])[tex]_2[/tex] + Ag

Balanced equation is the one in which the total number of atoms of a species on reactant side is equal to the total number of atoms on product side. The mass of the overall reaction should be conserved. There are so many types of chemical reaction reaction like combination reaction, displacement reaction.

The reaction between silver nitrate and copper is example of displacement reaction. Copper displaces silver from silver nitrate. to form copper nitrate.

Therefore, the balanced equation is of displacement type of reaction.

AgNO[tex]_3[/tex] + Cu [tex]\rightarrow[/tex] Cu(NO[tex]_3[/tex])[tex]_2[/tex] + Ag

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Answer:

not sure hope you have a good day

If the molar heat of vaporization for water is 40.7 kJ/mol. -40.7 kJ/mol is the molar heat of condensation.

Condensation, which is the opposite of vaporization, is the transformation of matter from its gaseous state into its liquid state. The water cycle is the most frequent use of the phrase. Another way to describe it is as the transformation of water vapor into liquid water when it comes into touch with a solid, liquid, or cloud condensation nucleus in the atmosphere.

Deposition is the term for the change that occurs when the gaseous phase directly transitions into the solid phase. Condensation is started when atomic or molecule clusters of such a species form within their gaseous volume, similar to how raindrops or snowflakes form within clouds, or when their gaseous phase comes into contact with a liquid and solid surface.

molar heat of vaporization = 40.7 kJ/mol

molar heat of condensation = -40.7 kJ/mol

Therefore, if the molar heat of vaporization for water is 40.7 kJ/mol. -40.7 kJ/mol is the molar heat of condensation.

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Answer:

When it rains or snows. Basically as soon as it hits the ground.

Explanation:

Groundwater begins as rain or snow that falls to the ground. This is called precipitation but only a small portion of this precipitation will become groundwater

Answer:

i am dancing and you ok hom

Answer:

7.19 g of Fe2O3 will produce 0.092 mole of iron

Explanation:

One mole of Fe2O3 reacts with 2 mole of Aluminum to produce one mole of Al2O3 and 2 mole of iron.

Mass of one mole of Fe2O3 = 159.69 g/mol

Thus, 159.69 g/mol of Fe2O3 produces two mole of Fe

7.19 g of Fe2O3 will produce

[tex]\frac{2}{156.9} * 7.19\\= 0.092[/tex]moles of iron

Answer:

Major periodic trends include: electronegativity, ionization energy, electron affinity, atomic radius, melting point, and metallic character.

Explanation:

These six are the major trends.

Answer:

d- The resulting pH will be equal to 7 because a strong base will neutralize a strong acid.

Explanation:

The reaction between potassium hydroxide and hydrochloric acid of equal volume and equal concentration yields a solution of pH 7 at equivalence point. We must note that KOH is a strong base while HCl is a strong acid. This fact influences the pH of the system at equivalence point.

Owing to the fact that the acid is exactly neutralized by the base; at the equivalence point of such titration, it is expected that hydrogen ions(H+) and hydroxide ions (OH-) must have reacted to form water, this leads to a final pH of 7.  

Answer:

Greenhouse gases absorb some of the energy and trap it in the lower atmosphere. Less heat radiates into space, and Earth is warmer. Many greenhouse gases occur naturally. Carbon dioxide, methane, water vapor, and nitrous oxide are naturally present in Earth's atmosphere. Since some of the extra energy from a warmer atmosphere radiates back down to the surface, Earth's surface temperature rises.

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Answer: The new pressure is 1.34 atm.

Explanation:

Given: [tex]P_{1}[/tex] = 10.8 atm,         [tex]T_{1} = 118^{o}C[/tex]

[tex]P_{2}[/tex] = ?,                  [tex]T_{2} = 948^{o}C[/tex]

Formula used to calculate the new pressure is as follows.

[tex]\frac{P_{1}}{T_{1}} = \frac{P_{2}}{T_{2}}\\\frac{10.8 atm}{118^{o}C} = \frac{P_{2}}{948^{o}C}\\P_{2} = 1.34 atm[/tex]

Thu, we can conclude that the new pressure is 1.34 atm.

Removal of an electron from stable, fully filled orbital requires more energy than removal of electron from partially filled orbital. Thus, ionisation enthalpy for Mg is greater than ionisation enthalpy for Al. So, the correct order of first ionization enthalpies is: Na<Mg>Al<Si.