Please help ………………….

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

Answer:

Plants ➯ Mouse ➯ Snake ➯ Hawk ➯ Sun

Explanation:

In Order As A Food Chain

The elements are arranged into food chain like plants ⇒Mouse ⇒ Snake⇒ Hawk ⇒ Sun.

A substance that could not be further decomposed according to any chemical reaction is known as a chemical element.

The flow of nutrients as well as energy through such an ecosystem is described by a food chain. Energy is first produced by plants at the most fundamental level, and then it is used by higher-level species like herbivores. Energy is then transmitted from one carnivore to the next when they eat the herbivores.

The elements are arranged into food chain like plants ⇒Mouse ⇒ Snake⇒ Hawk ⇒ Sun.

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Answer:

27 and 24 zeroes following it

Explanation:

10^25 is 100...(continues for 25 zeroes)

Now we multiply it by 2.7, making it 24 zeroes afterwards.

Avogadro's numbers are used to calculate the number of moles from molecules. There are 44.8 moles in MnO.

Molecules are the unit of the compound that may have the same or different atoms in it. The number of molecules is used to calculate moles from Avogadro's number.

By Avogadros number 1 mole of substance = 6.02 x 10²³ molecules

So, 2.7 x 10²⁵ molecules will have moles:

(2.7 x 10²⁵ molecules × 1 mole) ÷ (6.02 x 10²³ molecules) = 0.448 × 10² moles

Therefore, there are 44.8 moles of MnO.

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Explanation:

the answer will be A

The catalyst cannot be at point A since that's the reactant

Pathway B requires more energy, which makes it slower and harder for the reaction to finish

point D is the product

Answer:

B.

Explanation:

A spotaneous change is one which occurs on its own

A spontaneous change is one that occurs on its own.

A spontaneous process is a process which has a natural tendency to occur in one direction , It has no relation with the speed , It can be fast or it can be slow but it doesn't require any external factors to happen.

such reactions might not face change in energy but it will see change in the way the matter or energy is distributed

The example of a spontaneous reaction is the decay of radioactive elements.

Example of Spontaneous Process is also water flowing downhill, it has the natural tendency to flow in that direction.

A spontaneous change is one that occurs on its own.

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Answer:

It is approximately 9 moles

Explanation:

Divide the aluminum atoms by Avogadro's number

(5.42*10^24)/(6.02*10^23)

= approx. 9 moles

Answer:

40g de cromato sódico serán necesarios

Explanation:

Una solución 20% de Na2CrO4 contiene 20g de Na2CrO4 por cada 100g de solución (Esto es, soluto + solvente). Para preparar 200g de la disolución en mención serán necesarios:

200g solucion * (20g Na2CrO4 / 100g Solución) =

Answer:

Explanation:

125 cm3 -> 0.125 L

M = no. mole / volume (L)

M = 0.25 / 0.125 = 2 M

Answer:

Chlorine has atomic number 17. Its electronic configuration is 2, 8, 7. It is the second-lightest of the halogens, it appears between fluorine and bromine in the periodic table.

Answer:

III

Explanation:

From the periodic table, Chlorine(Cl) has 17 protons.

And when arranging the proton of elements each shell has a number protons it can take, i.e

2,8,8,8..........

The first shell can only take a maximum of 2 protons while the second shell upwards takes a maximum of 8 protons

Now we want to arrange Chlorine;

1st shell = 2

2nd shell = 8

2 + 8 = 10

17(no. of Chlorine protons) - 10

= 7

therefore,

3rd shell = 7

Therefore,

The electronic configuration of chlorine is

2,8,7

Answer: c. Shared equally between two atoms

Electrons are shared equally because the atoms have the same electronegativity.

Answer:

hearing aid

Explanation:

an artificial body part

A hearing aid is an example of a prosthesis. Therefore, option A is correct.

A prosthesis is an artificial device or replacement for a missing body part or function. In the case of a hearing aid, it is a device designed to assist people with hearing loss by amplifying sound. It acts as a substitute for the natural function of the ear.

A textbook is a written educational resource, gloves are protective coverings for the hands, and a pair of boots is footwear. These items do not serve as artificial replacements for missing body parts or functions.

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Answer:increases by a factor of 10

Explanation: the concentration of the solution changed from 4 to 3

Answer:

Matter is made of small particles of atoms or molecules. ... The particles in the solid are touching with very little space between them. The particles in a liquid usually are still touching but there are some spaces between them. The gas particles have big distances between them.

Answer:

Sketch 10 atoms of aluminum and 6 molecules of oxygen gas in the container on the left. In the right container, sketch the contents after the reaction is complete.

Explanation:

The balanced chemical equation of the reaction is:

[tex]4Al + 3 O_2 -> 2Al_2O_3[/tex]

Though there are 10 atoms of Al, only four atoms will react with every three molecules of oxygen.

Hence, right side the product formed is ---  Al2O3.

Answer:

Giant structures

Explanation:

An ionic compound is a giant structure of ions. The ions have a regular, repeating arrangement called an ionic lattice . The lattice is formed because the ions attract each other and form a regular pattern with oppositely charged ions next to each other.

Answer:

i think it is D

Explanation:

i dont know what you are learning but ecological succession is the change of enviroment pretty much.

Answer: The correct option is 1 mole of acetic acid was required for 2 moles of sodium bicarbonate

Explanation:

We are given:

Average number of drops of sodium bicarbonate = 142

The chemical equation for the reaction of sodium bicarbonate and acetic acid in vinegar follows:

[tex]NaHCO_3+CH_3COOH\rightarrow CH_3COONa+H_2CO_3[/tex]

From the stoichiometry of the reaction:

1 mole of sodium carbonate reacts with 1 mole of acetic acid in vinegar.

Hence, the correct option is 1 mole of acetic acid was required for 2 moles of sodium bicarbonate

Answer:

The element that has 16 electrons, 16 protons, and 16 neutrons is sulfur (S)

Explanation:

The atomic number tell you the number of protons.

The atomic configuration tell you the number of electrons.

The mass number minus the protons tell you the number of neutrons.

Answer:

CHCl₃

Explanation:

We have the following data:

C = 5.03 g

H = 0.42 g

Cl= 44.5 g

First, we divide each mass by the molar mass (MM) of the chemical element to calculate the moles:

MM(C) = 12 g/mol

moles of C = mass/MM(C) = 5.03 g/(12 g/mol) = 0.42 mol C

MM(H) = 1 g/mol

moles of H = mass/MM(H) = 0.42 g/(1 g/mol) = 0.42 mol H

MM(Cl) = 35.4 g/mol

moles of Cl = mass/MM(Cl) = 44.5 g/(35.4 g/mol) = 1.26 mol Cl

Now, we divide the moles by the smallest number of moles (0.42):

0.42 mol C/0.42 = 1 C

0.42 mol H/0.42 = 1 H

1.26 mol Cl/0.42 = 3 Cl

Thus, the C:H:Cl ratio is 1:1:3.

Therefore, the empirical formula is CHCl₃

Answer:

CHCl₃

Explanation:

Answer:

A.

Explanation:

PO WATER,AIR,WIND

Answer:

I think it's impure . Hope this helps you

Answer:

I think is pure but not 100% pure.

Explanation:

moles = mass/mr

=60.3/28

=2.15 moles

number of particles = moles × 6.02×10^23

= 2.15×6.02×10^23

= 1.29×10^24 atoms

CO=12+16=28

Answer:

1. Convert the mass of A to moles dividing in molar mass

2. Convert the moles of A to moles of D (2mol A = 3mol D)

3. Convert the moles of D to mass multiplying by its molar mass

Explanation:

As you can see in the equation, 2moles of A produce 3 moles of D, the equation is:

2mol A = 3mol D

But in the problem you are having the mass of A and you need the mass of D. That means you require to convert the mass of A to moles. With the moles of A you can find the moles of D and, as last, you need to convert the moles of A to mass.

To convert mass to moles or vice versa you must use Molar Mass. That means, the answer is:

The complete question is as follows: I want to make a homemade cake recipe you need 100 grams of sugar, calculate the moles to which it is equivalent and the number of molecules of sucrose.

Answer: In 100 grams of sugar there are 0.292 moles and the number of molecules of sucrose are [tex]1.76 \times 10^{23}[/tex].

Explanation:

Given: Mass = 100 g

Molar mass of sugar = 342.3 g/mol

As number of moles is the mass of substance divided by its molar mass.

Hence, moles of sucrose are calculated as follows.

[tex]Moles = \frac{mass}{molar mass}\\= \frac{100 g}{342.3 g/mol}\\= 0.292 mol[/tex]

According to mole concept, 1 mole of every substance contains [tex]6.022 \times 10^{23}[/tex] molecules.

Hence, the number of molecules present in 0.292 mol are calculated as follows.

[tex]0.292 mol \times 6.022 \times 10^{23}\\= 1.76 \times 10^{23}[/tex]

Thus, we can conclude that in 100 grams of sugar there are 0.292 moles and the number of molecules of sucrose are [tex]1.76 \times 10^{23}[/tex].

Explanation:

measuring the change of temperature when 2 liquids are mixed