1. What is the maximum amount of NaCl that can dissolve in
200 g of water? (The solubility of NaCl is 35 g/100 g H20 at
20°C.) *

Final answer:

STP for thermochemical equations is 273.15 K and 1 bar, previously it was 1 atm. It serves as a reference for reporting thermodynamic properties.

Explanation:

The standard conditions of temperature and pressure (STP) for a thermochemical equation are defined as a temperature of 273.15 K (0°C) and a pressure of 1 bar (100 kPa). It is important to note that previously, the old definition used a standard pressure of 1 atm. Under these conditions, we can calculate properties of gases and thermochemical data such as enthalpies of formation. For species in solution, the standard condition is a concentration of 1 Molar (1 mol/L). Pure substances are considered in their most stable form at 1 atm and at the standard temperature, unless otherwise noted in a specific text.

Significance of STP in Thermochemical Equations

The significance of STP in thermochemical equations lies in its use as a benchmark for reporting the thermodynamic properties of substances. This consistent baseline allows for the comparison and understanding of data, such as enthalpies of formation, which are essential for studying chemical reactions and processes.

The answer is option A - 0°C and 101 kPa. Standard conditions of temperature and pressure for a thermochemical equation are 0°C and 101 kPa.

Standard conditions of temperature and pressure (STP) for thermochemical equations are 0°C and 101 kPa, equating to 0°C (273.15 K) and 1 bar (100 kPa). This set of conditions is referred to as standard temperature and pressure (STP), which is defined as 0°C (273.15 K) and 1 bar (100 kPa). However, it's important to note that there have been different definitions over time, with an older definition using 1 atm (101.325 kPa) instead. For most thermochemical data and calculations, STP is used as a reference point to enable comparisons of the properties of different gases.

The question is:

Standard conditions of temperature and pressure for a thermochemical equation are _____.

A. 0°C and 101 kPa.

B. 25°C and 101 kPa.

C. 0°C and 0 kPa.

D. 25°C and 22.4 kPa.

Answer:

nucleus

Explanation:

it holds information needed to regulate most of the cell functions

The 'brain' of the cell is the nucleus, which regulates cell activities by managing genetic material and essential functions like growth and protein synthesis. It ensures the proper functioning of the cell, similar to the role of the human brain, which controls both mental and physical processes.

The "brain" of the cell is commonly referred to as the nucleus. Like the human brain, which is the control center of the body, the nucleus regulates the activities of the cell. It holds the cell's genetic material and is responsible for managing activities such as growth, metabolism, protein synthesis, and cell division.

The human brain, on the other hand, controls mental processes such as reasoning, imagination, memory, and language as well as physical processes like breathing and heartbeat. Both the nucleus and the human brain are essential for the proper functioning of their respective systems.

A typical day in the life of a cell involves the nucleus sending instructions for protein synthesis, which are necessary for the cell to carry out specific functions. Without the nucleus, a cell would not be able to operate efficiently, just as without the human brain, a body could not function.

Answer: This is because their valence electrons are located in the S - orbital

Explanation:

This is because their valence electrons are located in the S - orbital.

Answer:

4.704625 kJ (or 4704.625 J) is the amount of heat absorbed when the temperature of 75 grams of water increases from 20.°C to 35°C.

Explanation:

The measurement and calculation of the amounts of heat exchanged by a body or system is called calorimetry.

In this way, there is a direct proportionality relationship between heat and temperature. The constant of proportionality depends on the substance that constitutes the body as its mass, and the product of specific heat is produced by the body's mass. So, the equation that allows to calculate heat exchanges is:

Q = c * m * T

Where Q is the heat exchanged for a body of mass m, constituted by a specific heat substance c and where T is the temperature variation.

In this case:

Then:

[tex]Q= 4.181 \frac{J}{g C} * 75 g *15 C[/tex]

Q≅4704.625 J

Being 1 kJ = 1000 J:

Q=4.704625 kJ

Finally, 4.704625 kJ (or 4704.625 J) is the amount of heat absorbed when the temperature of 75 grams of water increases from 20.°C to 35°C

When the temperature of 75 grams of water increases from 20 °C to 35 °C, the heat absorbed is 1125 calories, calculated using the specific heat formula (q = mcΔT).

The question asks about the amount of heat absorbed when the temperature of a certain amount of water increases. We can calculate this using the specific heat formula: q = mcΔT, where 'q' is the heat absorbed, 'm' is the mass of the water, 'c' is the specific heat of water, and 'ΔT' is the change in temperature.

Given: m = 75 g (mass of water), c = 1.00 cal/g °C (specific heat of water), and ΔT = 35°C - 20°C = 15°C (change in temperature).

Plugging these values into the formula gives: q = (75 g) x  (1.00 cal/g °C) x (15°C) = 1125 cal.

So, when the temperature of 75 grams of water increases from 20°C to 35°C, it absorbs 1125 calories of heat.

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Answer:

Only 10 mole of water will react with 10 mole of Na metal

and produce

                     10Na + 10H₂O --------------> 10NaOH + 5H₂

Explanation:

2Na + 2H₂O -------------> 2NaOH + H₂

Exothermic Reaction:

This reaction is supper exothermic and when sodium metal react with water it produce a lot of heat.

Limiting Reagent:

Limiting reagent is the amount of reactant in a chemical reaction that determines the amount of products that will be produce.

For instance we will use the same equation

2Na + 2H₂O --------------> 2NaOH + H₂

The reaction shows that 2 mole of sodium combine with 2 mole of water and will produce 2 mole of NaOH and 1 mole of Hydrogen gas.

if we increase the amount of  water  to 4 mole then the same amount of product will form, and the extra water will remain unracted.

Similarly if we increase amount of Na to 4 mole then only 2 mole will react and will produce same amount.

Now

if we add 10 mole of Na to a large Volume of water following thing will happen

Given Reaction:

                  2Na + 2H₂O --------------> 2NaOH + H₂

Data from Reaction:

                   2Na +  2H₂O --------------> 2NaOH + H₂

                   2 mole   2mole                   2mole      1mole

Applying unity formula:

2 mole of Na will react with 2mole of water

So

                       2 mole of Na ≅ 2mole of H₂O

                       10 mole of Na = 10 mole of H₂O

So the same reaction will occur and produce NaOH and hydrogen gas

So, From the above reaction

                          2 mole of Na ≅ 2mole of NaOH

if 2 mole of Na produces 2 mole of NaOH then 10 mole will produce how much NaOH

apply the unity formula

2 mole of the Na ≅ 2 mole of NaOH

10 mole of the Na ≅ X mole of NaOH

so by cross multiplication

2 mole of Na x X mole of NaOH ≅ 2 mole of NaOH x 10 mole of the Na

we have to find moles of NaOH ....so by rearrangement of the above equation

X mole of NaOH = 2 mole x 10 mole

                                       2 mole

X mole of NaOH= 10 mole

So

10 mole of Na will produce 10 mole NaOH

*****For Hydrogen Gas that produce :

                         2 mole of Na ≅ 1 mole H₂

If 2 mole of Na produces 1 mole of H₂ then 10 mole will produce how much H₂

apply the unity formula

2 mole of the Na ≅ 1 mole of H₂

10 mole of the Na ≅ X mole of H₂

so by cross multiplication

2 mole of Na x X mole of H₂ ≅ 1 mole of H₂ x 10 mole of the Na

we have to find moles of H₂ ....so by rearrangement of the above equation

X mole of H₂ = 1 mole x 10 mole

                                       2 mole

X mole of H₂ = 5 mole

So

The following will be reaction if 10 moles Na thrown in large volume of water

Only 10 mole of water will react with it

                     10Na + 10H₂O --------------> 10NaOH + 5H₂ and heat

Answer:

Sodium and Magnesium are the two different element having same number of neutrons.

Explanation:

Neutron:

It is a subatomic particle,but without an electric charge,present in all the atomic nuclei except those of ordinary hydrogen.

Its symbol is n with no charge on it.

sodium and magnesium have the same number of neutrons.

name of the element : Sodium

symbol: Na

atomic number: 11

number of protons: 11

number of neutrons: 12

number of electrons: 11

distribution of electrons: 2 , 8 , 1  

valency: 1

name of the element : Magnesium

symbol: Mg.

atomic number: 12

number of protons: 12

number of neutrons: 12

number of electrons: 12

distribution of electrons: 2 , 8 , 2  

valency: 2

Both are considered mixtures - that is, they are made up of two or more pure substances. ... A heterogeneous mixture appears to be made of different substances. A solution appears the same throughout. In the fluid phase (gas or liquid, or any combination of those) a solution is transparent (thought not colourless).

Final answer:

Heterogeneous mixtures have non-uniform composition and can be differentiated by eye, while solutions have uniform composition throughout and no settling occurs.

Explanation:

A heterogeneous mixture is a combination of two or more substances in which the composition is not uniform throughout the sample, and the individual substances can be differentiated by eye. Examples of heterogeneous mixtures include trail mix, salad, and blood. On the other hand, a solution is a type of homogeneous mixture where the composition is uniform throughout and no settling occurs. Solutions can be colored but are transparent, and the dissolved species are molecules or ions. Examples of solutions include air, simple syrup, and seawater.,

Answer:

x = 5.9

Explanation:

The volume of a gas sample at STP (2.5 L and 273 K) that is heated to 273 degrees Celsius at constant pressure will double to 5.0 L.

To solve this, we'll use Charles's Law, which states that the volume of a gas is directly proportional to its temperature (in Kelvins) when pressure is held constant. The formula for Charles's Law is V1/T1 = V2/T2. The initial volume (V1) is 2.5 L and the initial temperature (T1) is 273 K (which is STP). The final temperature (T2) is 273 degrees Celsius, which needs to be converted to Kelvins by adding 273, resulting in T2 = 546 K.

Now, we can solve for the new volume (V2):

So, when the temperature is raised to 273 degrees Celsius and the pressure remains constant, the new volume of the gas will be 5.0 L.

Answer:

'Low reactivity'  is common property of noble gases.

Explanation:

The properties of noble gases are:

Answer:

nani

Explanation:

omeo wa moo shindau nani

(proberly spelt it wrong too.)

Answer:

The final mass of sample is 1.3 g.

Explanation:

Given data:

Half life of H-3 = 12.32 years

Amount left for 15.0 years = 3.02 g

Final amount = ?

Solution:

First all we will calculate the decay constant.

t₁/₂ = ln² /k

t₁/₂ =12.32 years

12.32 y =  ln² /k

k = ln²/12.32 y

k = 0.05626 y⁻¹

Now we will find the original amount:

ln (A°/A) = Kt

ln (3.02 g/ A) = 0.05626 y⁻¹ × 15.0 y

ln (3.02 g/ A) = 0.8439

3.02 g/ A = e⁰°⁸⁴³⁹

3.02 g/ A = 2.33

A = 3.02 g/ 2.33

A = 1.3 g

The final mass of sample is 1.3 g.

Answer:

The anwer is 1.30 in plato

Explanation:

Answer:

27.7  × 10²³ atoms

Explanation:

Given data:

Number of moles of Potassium = 4.6 mol

Number of atoms = ?

Solution:

The given problem will solve by using Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.

The number 6.022 × 10²³ is called Avogadro number.

For example,

18 g of water = 1 mole = 6.022 × 10²³ molecules of water

1.008 g of hydrogen = 1 mole = 6.022 × 10²³ atoms of hydrogen

For 4.6 moles of K:

One mole = 6.022 × 10²³ atoms

4.6 mol × 6.022 × 10²³ atoms= 27.7  × 10²³ atoms

Answer:

fossils

land features

Explanation:

if some lands had similar fossil types, it must mean that the lands were once in the proximity of each other. For example, if Africa had the same fossils as South America, it must mean that they once we're connected, so that the animals can move freely from one continent to another. Additionally, the land features of some continents are similar to a jigsaw puzzle. It seems as though we can connect the edges based on their shape.

new SUBSTANCES are fomed

Answer:

Mass =  0.89 g

Explanation:

Given data:

Moles of diphenylmethanol = 4.82 mmol

Mass = ?

Solution:

we will convert the mmol into mols.

4.82 /1000 = 0.0048 mol

Molar mass of  diphenylmethanol  = 184.23 g/mol

Formula:

Mass = number of moles × molar mass

Mass =  0.0048 mol × 184.23 g/mol

Mass =  0.89 g

Answer:

20 Liters

Explanation:

If the pressure is supposed to be constant, one of Charles - Gay Lussac's laws can be used to solve the exercise. His statement says that "the volume of the gas is directly proportional to its temperature at constant pressure", mathematically it would be:

[tex]\frac{V1}{T1} = \frac{V2}{T2}[/tex]

Considering T₁ = 50 ° C; V₁ = 10.0 L; and T₂ = 100 ° C, we can calculate the volume V₂ Clearing it from the equation and replacing the values to perform the calculation:

V2= (V1 x T2) / T1  = (10.0 L x  100°C)  / 50 °C = 20 L

Therefore, the gas at 100 ° C will occupy a volume of 20.0 L.

To find the volume a gas will occupy at a higher temperature at constant pressure, use Charles's Law formula V1/T1 = V2/T2. After converting Celsius to Kelvin, solving the problem indicates the new volume at 100 °C would be approximately 11.54 L.

The question involves calculating the change in volume of a gas when it is subjected to a change in temperature, knowing that the pressure is held constant. This is a problem that can be addressed using Charles's Law, which states that the volume of a gas is directly proportional to its temperature on a Kelvin scale. To solve the problem, you must first convert the temperatures from Celsius to Kelvin by adding 273.15 to each temperature. Once you have the temperatures in Kelvin, you can use the formula V1/T1 = V2/T2, where V1 is the initial volume, T1 is the initial temperature, V2 is the final volume, and T2 is the final temperature.

In this case, the initial temperature is 50 °C (323.15 K) and the final temperature is 100 °C (373.15 K). The initial volume is 10.0 L, and you are solving for the final volume.

Using the formula:

V2 = V1 * (T2/T1) = 10.0 L * (373.15 K / 323.15 K) = 11.54 L

This is the volume the gas will occupy at 100 °C at constant pressure.

Answer:Energy is coverted into a waterfall

Explanation:Answer:A waterfall is a sudden drop in a river as it flows over a rock cliff. This happens when the river passes from a layer of hard rock to a layer of softer rock, and the water erodes away the softer rock. A watershed is the term given to the land that drains water into a particular stream, lake, or river.

Answer:

N₂ + 3H₂  →  2NH₃

2H₂O →  2H₂ + O₂

CH₄ + 2O₂  →  CO₂ + 2H₂O

Explanation:

A) Make ammonia:

Chemical equation:

N₂ + H₂  →  NH₃

Balanced chemical equation:

N₂ + 3H₂  →  2NH₃

Step one:

N₂   +   H₂      →     NH₃

N = 2                    N = 1

H = 2                    H = 3

Step 2:

N₂   +   3H₂      →          2NH₃

N = 2                              N = 1

H = 2×3 = 6                    H = 3×2 = 6

Step 3:

N₂   +   3H₂      →          2NH₃

N = 2                              N = 1×2 = 2

H = 2×3 = 6                    H = 3×2 = 6

B) separate water:

Chemical equation:

H₂O →  H₂ + O₂

Balanced chemical equation:

2H₂O →  2H₂ + O₂

Step one:

H₂O        →        H₂ + O₂

H = 2                    H = 2

O = 1                     O = 2

Step 2:

2H₂O                →        H₂ + O₂

H = 2×2 = 4                  H = 2

O = 1×2 =2                     O = 2

Step 3:

2H₂O                →        2H₂ + O₂

H = 2×2 = 4                  H = 2×2 = 4  

O = 1×2 =2                     O = 2

C) Combust methane

Chemical equation:

CH₄ + O₂  →  CO₂ + H₂O

Balanced chemical equation:

CH₄ + 2O₂  →  CO₂ + 2H₂O

Step one:

CH₄ + O₂  →  CO₂ + H₂O

C = 1                    C = 1

H = 4                   H = 2

O = 2                    O = 3

Step 2:

CH₄ + 2O₂  →  CO₂ + H₂O

C = 1                     C = 1

H = 4                    H = 2

O = 2×2 = 4          O = 3

Step 3:

CH₄ + 2O₂  →  CO₂ + 2H₂O

C = 1                    C = 1

H = 4                   H = 2×2 = 4  

O = 2×2 = 4         O = 2 + 2 = 4

Answer:

The explanation is given below

Explanation:

Dalton was the first who putted forward the theory about atom. he describe the properties of atoms of the element. Dalton based his theory on the law of conservation of mass and the law of constant composition.

His theory has 5 basic postulates and these five principals are still true.

1. Dalton stated that all matter composed of atoms are very small in size. these smallest unit of matter (atom) take part in chemical reaction.

2. All the atoms of an element are similar in shape, size, and other properties but different from the atoms of other element.

3. This theory states all matter is made up of atoms and atom can not be created nor destroy.

4. Law of constant composition:

According to this: atoms of different elements combine in a simple, fixed and whole number ratio to form compound.

5. Atoms the element can combine in more than one ratio and form two or more compounds.

The atomic theory of Dalton explained many things.

Other models are its modification and explanation. Dalton was the first who recognize difference between atom of an element compound.

Although there are some discrepancies to explain other points but these 5 points are still workable and true.

The principle that still holds true from Dalton's atomic theory is the law of conservation of matter.

Even though new models were discovered after Dalton created his five principles, one principle that still holds true is the idea that atoms are neither created nor destroyed during a chemical change, which is known as the law of conservation of matter. This means that the total mass of matter present in a chemical reaction remains constant.

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Answer:

B. A chart of frequencies of light waves

Explanation:

Answer:

b

Explanation:

Answer:

Here's what I get  

Explanation:

In a single replacement reaction, one element must displace another element from its compound.

Thus, we must consider the reactivity series, because an element lower down in the series cannot replace one that is above it.

In a double replacement reaction, the cations change partners with the anions. All we need consider are the solubilities of the new cation-anion partners.

In a single replacement reaction, it is mandatory that one element displaces the other according to their reactivity on the reactivity series.

On the other hand, In a double- displacement reaction; the cations just exchange anions and vice versa.

An example of a single displacement reaction is;

An example of a double displacement reaction is;

As such, there's no preference in double displacement reactions as ions are swapped.

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Answer:

There will be more repulsive force between the electrons.

Explanation:

Electrons contain negative charge.As a result the electron will repulse another adjacent negatively charged electron.

   According to the given question addition of electrons to en energy level without adding more protons will increase the overall negative charge in the the energy level in which the electrons are added.

  This ultimately leads to generate more repulsive force between the electrons.

Lead-205 (Pb-205)

We are given;

We are supposed to identify its product after an alpha decay;

²⁰⁹₈₄Po → ²⁰⁵₈₂Pb + ⁴₂He

Explanation:

The gravitational force between two 50kg objects could be less than the gravitational force between a 50kg and a 5kg object if the two 50kg objects are much farther apart.

Answer:

By increasing the distance between the two 50 kg objects compared with the distance between the 5 kg objects.

Explanation:

The formula for the force between 2 objects is

Fg   = (G m1 m2) / r^2

where Fg is the force,  G = gravitational constant, m1 and m2 are the masses of the objects and r = the distance between the objects.

So as r is increased  Fg is  decreased.

The water molecules are not completely removed so additional heating is required.

Explanation:

We have the copper (II) sulfate pentehydrate with the chemical formula CuSO₄ · 5H₂O.

molar mass of CuSO₄ · 5H₂O = 159.6 + 5 × 18 = 249.6 g/mole

Knowing this, we devise the following reasoning:

if in       249.6 g of CuSO₄ · 5H₂O there are 90 g of H₂O

then in         8 g of CuSO₄ · 5H₂O there are Y g of H₂O

Y = (8 × 90) / 249.6 = 2.88 g of water

mass of dried CuSO₄ = mass of CuSO₄ · 5H₂O -  mass of H₂O

mass of dried CuSO₄ = 8 - 2.88 = 5.12 g

5.12 g is less that the weighted mass of 6.50 g. We deduce from this that the sample needs additional heating in order to remove all the water (H₂O) molecules.

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hydrates

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Answer:

Details are below

Explanation:

A Compound is made of number of atom of element, that have a specific ratio.

Below are the details of elements and the number of its atoms:

1) NaOH

Element    :  #of atoms

Na                      1

O                        1

H                        1

__________________

Total                  3

---------------------------------

2) HNO₃

Element    :  #of atoms

H                      1

N                      1

O                      3

___________________

Total                 4

----------------------------------

3) Li₂O

Element    :  #of atoms

Li                     2

O                      1

__________________

Total                3

------------------------------------

4) Li₂SO₄

Element    :  #of atoms

Li                     2

S                      1

O                      4

____________________

Total                 7

------------------------------------------

5) NH₄Cl

Element    :  #of atoms

N                     1

Cl                     1

H                      4

____________________

Total                6

------------------------------------------

6) CaClO₃

Element    :  #of atoms

Ca                    1

Cl                     1

O                      3

____________________

Total                 5

------------------------------------------

7) H₂COCH₂

Element    :  #of atoms

C                     2

H                     4

O                     1

____________________

Total                 7

------------------------------------------

8) Mg(OH)₂

Element    :  #of atoms

Mg                   1

H                     2

O                     2

____________________

Total                5

------------------------------------------

9) Al(OH)₃

Element    :  #of atoms

Al                    1

H                     3

O                     3

____________________

Total                 7

------------------------------------------

10) NH₄C₂H₃O₂

Element    :  #of atoms

N                     1

H                     7

C                     2

O                     2

____________________

Total                12

------------------------------------------

11) NaC₂H₃O₂

Element    :  #of atoms

Na                     1

H                       3

C                       2

O                       2

____________________

Total                 8

------------------------------------------

12) (NH₄)₃ PO₄

Element    :  #of atoms

N                     3

H                     12

P                      1

O                      4

____________________

Total                20

----------------------------------------------

Each molecule has a distinct composition of atoms, and the total number of atoms varies based on the elements present and their respective quantities in each compound.

1. **NaOH (Sodium Hydroxide):**

  - Sodium (Na): 1 atom

  - Oxygen (O): 1 atom

  - Hydrogen (H): 1 atom

  - Total: 3 atoms

2. **HNO3 (Nitric Acid):**

  - Nitrogen (N): 1 atom

  - Oxygen (O): 3 atoms

  - Hydrogen (H): 1 atom

  - Total: 5 atoms

3. **Li2O (Lithium Oxide):**

  - Lithium (Li): 2 atoms

  - Oxygen (O): 1 atom

  - Total: 3 atoms

4. **Li2SO4 (Lithium Sulfate):**

  - Lithium (Li): 2 atoms

  - Sulfur (S): 1 atom

  - Oxygen (O): 4 atoms

  - Total: 7 atoms

5. **NH4Cl (Ammonium Chloride):**

  - Nitrogen (N): 1 atom

  - Hydrogen (H): 4 atoms

  - Chlorine (Cl): 1 atom

  - Total: 6 atoms

6. **CaClO3 (Calcium Chlorate):**

  - Calcium (Ca): 1 atom

  - Chlorine (Cl): 1 atom

  - Oxygen (O): 3 atoms

  - Total: 5 atoms

7. **H2COCH2 (Formaldehyde):**

  - Carbon (C): 2 atoms

  - Oxygen (O): 1 atom

  - Hydrogen (H): 4 atoms

  - Total: 7 atoms

8. **Mg(OH)2 (Magnesium Hydroxide):**

  - Magnesium (Mg): 1 atom

  - Oxygen (O): 2 atoms

  - Hydrogen (H): 2 atoms

  - Total: 5 atoms

9. **Al(OH)3 (Aluminum Hydroxide):**

  - Aluminum (Al): 1 atom

  - Oxygen (O): 3 atoms

  - Hydrogen (H): 3 atoms

  - Total: 7 atoms

10. **NH4C2H3O2 (Ammonium Acetate):**

   - Nitrogen (N): 1 atom

   - Hydrogen (H): 7 atoms

   - Carbon (C): 2 atoms

   - Oxygen (O): 2 atoms

   - Total: 12 atoms

11. **NaC2H3O2 (Sodium Acetate):**

   - Sodium (Na): 1 atom

   - Hydrogen (H): 3 atoms

   - Carbon (C): 2 atoms

   - Oxygen (O): 2 atoms

   - Total: 8 atoms

12. **(NH4)3PO4 (Ammonium Phosphate):**

   - Nitrogen (N): 3 atoms

   - Hydrogen (H): 12 atoms

   - Phosphorus (P): 1 atom

   - Oxygen (O): 4 atoms

   - Total: 20 atoms

In summary, each molecule has a distinct composition of atoms, and the total number of atoms varies based on the elements present and their respective quantities in each compound.

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Answer:

1. The atoms in propane and oxygen rearrange to form other substances after the reaction.

Explanation:

Chemical change:

The changes, that occur due to change in the composition of a substance and result in a different compound is known as chemical change.

These changes are irreversible

These changes occur due to chemical reactions

These may not be observed with naked eye

Example:

Combustion of fuel or wood: that oil or wood convert into energy, CO2 and ash in case of wood

Boiling of egg: that change the chemical composition of protein in the egg .

The burning of propane is also a chemical change because propane and oxygen converted into water and carbon dioxide by rearrangement of atoms.

C₃H₈ + 5O₂ → 3CO₂ + 4H₂O

Answer:

the answer is a

Explanation:

According to the pH scale, baking soda is a weak base while bleach is a strong base. Therefore, option (A) is correct.

An acid is any substance that is capable of donating a proton to another substance.  A base is a molecule or ion that is capable to accept a hydrogen ion from an acid.

Acidic substances are generally identified by their sour taste. An acid is commonly a molecule that can donate an H⁺ ion and can be energetically favorable after a loss of H⁺ ion. Acids are also known to turn blue litmus paper into the red.

Bases are characterized by a bitter taste and a slippery texture. A base t can dissolve in water is also referred as an alkali. When bases chemically react with acids, they yield salts and water as products. Bases are also known to turn red litmus paper into the blue.

The pH value of the acids lies between 0 to 7 and the pH value of the acids lies between 7 to 14. Baking soda is a weak base that has a pH value of around 8 to 9 and bleach is a strong base that has a pH value of around 13.

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