read carefully and do this questions all part all questions if someone do this questions I will make you brainly and give you thanks.

a. This reaction is endothermic because energy is absorbed during the reaction.

b. ΔH = +187 kJ

c. The balanced chemical equation for the decomposition of calcium carbonate is:

CaCO3(s) → CO2(g) + CaO(s)

d. We can use the molar mass of calcium carbonate to convert 21.0 g of CaCO3 to moles:

21.0 g CaCO3 x (1 mol CaCO3 / 100.09 g CaCO3) = 0.210 mol CaCO3

From the balanced equation, we can see that the molar ratio of CaCO3 to ΔH is 1:1. Therefore, the energy absorbed can be calculated as:

0.210 mol CaCO3 x 187 kJ/mol = 39.3 kJ

Therefore, 39.3 kJ of energy is absorbed during the decomposition of 21.0 g of calcium carbonate.

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Answer:

Explanation:Canguru comeu algumas folhas de 3 galhos de eucalipto. Cada galho tinha inicialmente20 folhas. Canguru comeu algumas folhas do primeiro galho e depois comeu tantas folhas do segundo galho quantas tinham sido deixadas no primeiro galho. Depois ele comeu 2 folhas do terceiro galho. No total, quantas folhas foram dei-xadas nos 3 galhos?Canguru comeu algumas folhas de 3 galhos de eucalipto. Cada galho tinha inicialmente20 folhas. Canguru comeu algumas folhas do primeiro galho e depois comeu tantas folhas do segundo galho quantas tinham sido deixadas no primeiro galho. Depois ele comeu 2 folhas do terceiro galho. No total, quantas folhas foram dei-xadas nos 3 galhos?Canguru comeu algumas folhas de 3 galhos de eucalipto. Cada galho tinha inicialmente20 folhas. Canguru comeu algumas folhas do primeiro galho e depois comeu tantas folhas do segundo galho quantas tinham sido deixadas no primeiro galho. Depois ele comeu 2 folhas do terceiro galho. No total, quantas folhas foram dei-xadas nos 3 galhos?Canguru comeu algumas folhas de 3 galhos de eucalipto. Cada galho tinha inicialmente20 folhas. Canguru comeu algumas folhas do primeiro galho e depois comeu tantas folhas do segundo galho quantas tinham sido deixadas no primeiro galho. Depois ele comeu 2 folhas do terceiro galho. No total, quantas folhas foram dei-xadas nos 3 galhos?Canguru comeu algumas folhas de 3 galhos de eucalipto. Cada galho tinha inicialmente20 folhas. Canguru comeu algumas folhas do primeiro galho e depois comeu tantas folhas do segundo galho quantas tinham sido deixadas no primeiro galho. Depois ele comeu 2 folhas do terceiro galho. No total, quantas folhas foram dei-xadas nos 3 galhos?

This element is in group 1.

According to the octet rule, this element would be expected to form an ion with a charge of +1.

If X is in period 5, the ion formed has the same electron configuration as the noble gas Krypton

The symbol for the ion is Rb⁺

Electronic configuration refers to the arrangement of electrons in the orbitals of an atom or molecule, indicating the energy level of the electrons, the number of electrons in each energy level, and the number of electrons in each orbital.

Considering the given element:

It has one valence electron, hence it is in group 1. Group 1 elements form ions with a charge of +1.

Losing one electron will give the ion the same electron configuration as Kyrton since it is the noble gas in Period 4.

The element is rubidium and the ion is Rb⁺.

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Answer:

--->

Explanation:

the change of oxygen from solid to liquid would be that at the solid phase the color would be light blue and changes to colorless on the liquid phase

When oxygen transitions from solid to liquid, its colour changes from bright blue in the solid state to colourless in the liquid state.

The periodic table's Group 16 (also known as the oxygen group) contains the nonmetallic chemical element oxygen (O). Oxygen is a colourless, odourless, and tasteless gas that is necessary for all living things. Animals take it up and then change it into carbon dioxide, which plants then use as a source of carbon and release the oxygen back into the atmosphere.

As well as reactions that remove elements from their combinations with one another, oxygen may react with nearly any other element to produce compounds. These reactions, which are frequently accompanied by the development of heat and light, are known as combustions. Water is the most significant component.

Therefore, when oxygen transitions from solid to liquid, its colour changes from bright blue in the solid state to colourless in the liquid state.

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The balanced equation for the reaction is:

Zn + 2HCl → ZnCl2 + H2

According to the stoichiometry of the equation, 1 mole of Zn reacts with 2 moles of HCl to produce 1 mole of H2 and 1 mole of ZnCl2.

Therefore, if 6.0 moles of Zn react with 6.0 moles of HCl, we need 12.0 moles of HCl to react completely with all the Zn. This means that HCl is the limiting reactant, as there are not enough moles of HCl to react with all the Zn.

So, the answer is (D) HCl.

Answer:

when placed in water, a sodium pellet catches on fire as hydrogen gas is liberated and sodium hydroxide forms. chemical change = fire is a sign of chemical reaction.

Explanation:

When placed in water the sodium pellets catch the fire and liberate the hydrogen gas. On mixing with water solid sodium forms a colorless basic solution.

Sodium is a soft metal. It is a very reactive element with a low melting point. Sodium reacts very quickly with water, snow, and ice to produce sodium hydroxide and hydrogen. It is an alkali metal and the sixth most abundant metal on earth. It has a silvery white color.

It has a strong metallic luster. On reacting with oxygen it produces sodium oxide which on reacting with the water produces sodium hydroxide.

It is used to improve the structure of certain alloys and soaps. It is also used in the purification of metals. Sodium is also present in sodium chloride, an important compound found in the environment.

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The net ionic equation for the reaction between potassium sulfide and magnesium iodide is S2- + Mg2+ -> MgS, as the potassium and iodide ions are spectator ions and do not participate in the reaction.

To determine the net ionic equation for the reaction between potassium sulfide (K2S) and magnesium iodide (MgI2), we first need to identify the ions present in each compound and then determine the products formed when they react.

Potassium sulfide (K2S) dissociates into two potassium ions (K+) and one sulfide ion (S2-):

K2S -> 2K+ + S2-

Magnesium iodide (MgI2) dissociates into one magnesium ion (Mg2+) and two iodide ions (I-):

MgI2 -> Mg2+ + 2I-

Now, we need to determine the possible products when these ions combine. Since potassium (K+) has a +1 charge and iodide (I-) has a -1 charge, they can combine to form potassium iodide (KI):

K+ + I- -> KI

Similarly, magnesium (Mg2+) and sulfide (S2-) can combine to form magnesium sulfide (MgS):

Mg2+ + S2- -> MgS

Now, we can write the complete ionic equation by representing all the ions present before and after the reaction:

2K+ + S2- + Mg2+ + 2I- -> 2KI + MgS

To obtain the net ionic equation, we remove the spectator ions, which are the ions that appear on both sides of the equation and do not participate in the actual reaction. In this case, the spectator ions are the potassium ions (K+) and the iodide ions (I-).

Thus, the net ionic equation for the reaction between potassium sulfide and magnesium iodide is:

S2- + Mg2+ -> MgS

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Answer:I think it's in the same column as a sodium on the periodic table because chemical properties are based on their electron structure and the columns called groups are elements with the same shell structure which increases in mass as you go down the column, therefore the elements which are similar to sodium must be in the same group.

Explanation:

The balanced chemical equation for the reaction is:

PCl5 + H2O → H3PO4 + HCl

To balance this equation, we need to make sure that the number of atoms of each element is equal on both sides of the equation.

To do this, we can start by balancing the phosphorus (P) and chlorine (Cl) atoms. There is one P atom and five Cl atoms on the left side of the equation, and one P atom and one Cl atom on the right side of the equation. We can balance these by adding a coefficient of 5 in front of HCl:

PCl5 + H2O → H3PO4 + 5HCl

Now we have five Cl atoms on both sides of the equation. Next, we can balance the hydrogen (H) atoms. There are two H atoms on the left side of the equation and five H atoms on the right side of the equation. We can balance these by adding a coefficient of 2 in front of H2O:

PCl5 + 2H2O → H3PO4 + 5HCl

Now we have two H atoms on both sides of the equation. Finally, we can balance the oxygen (O) atoms. There are two O atoms on the left side of the equation and four O atoms on the right side of the equation. We can balance these by adding a coefficient of 2 in front of H3PO4:

PCl5 + 2H2O → 2H3PO4 + 5HCl

Therefore, to balance this reaction, we need to use this balanced chemical equation:

PCl5 + 2H2O → 2H3PO4 + 5HCl

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The rate constant for the reaction is either 7.14×10−3 s−1 or 2.50×10−3 s−1, depending on which rate was used to calculate it.

The rate of the reaction is given by the equation:

Rate = -k[A]

where k is the rate constant and [A] is the concentration of the reactant.

Rate at t=140 s:

Rate = (8.00×10−2 M - 0 M) / (140 s - 0 s)

= 5.71×10−4 M/s

Rate at t=400 s:

Rate = (4.00×10−2 M - 0 M) / (400 s - 0 s)

= 1.00×10−4 M/s

Since this is a zero-order reaction, the rate of the reaction is constant, and we can use either rate to calculate the rate constant:

k = Rate / [A]

Using the rate at t=140 s:

k = 5.71×10−4 M/s / 8.00×10−2 M = 7.14×10−3 s−1

Using the rate at t=400 s:

k = 1.00×10−4 M/s / 4.00×10−2 M

= 2.50×10−3 s−1

The rate constant for the reaction is either 7.14×10−3 s−1 or 2.50×10−3 s−1.

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Answer:

\(f=2x10^8Hz\)

Explanation:

Hello!

In this case, given that frequency of the electromagnetic radiation showing off a wavelength of 1.25 m is computed by using the speed of light as shown below:

\(f=\frac{c}{\lambda }\)

We plug in the wavelength and speed of light to obtain:

\(f=\frac{3x10^8m/s}{1.25m } \\\\f=2x10^8Hz\)

Best regards!

The frequency will be "\(2\times 10^8 \ Hz\)".

Radiation which thus travels throughout waves as well as which has both electromagnetic energy.

The power of electromagnetic radiation could range from minimum to maximum. Radio waves, radiation, x-rays, and gamma radiation are all examples of electromagnetic radiation.

Given value:

Wavelength, \(\lambda = 1.25 \ m\)

Speed of light, \(c = 3\times 10^8\) m/s

The frequency be:

→ \(f = \frac{c}{v}\)

By putting the values,

     \(= \frac{3\times 10^8}{1.25}\)

     \(= 2\times 10^8\) Hz

Thus the above response is right.

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Answer:

A. 52.11%

Explanation:

Percentage of Oxygen= (mass of Oxygen in glycerol/ mass of glycerol) x 100

                                     = ((16*3)/ 92.11) x 100

                                     =52.11%

The number of moles of the sodium chlroide from the calculation is 0.11 moles.

We can connect a substance's mass to its particle count using the concept of a mole. A material's molar mass, which is measured in grams per mole, is the mass of one mole of that substance. One mole of carbon-12 atoms, for instance, weighs 12 grams according to its molar mass of 12 grams/mol.

We have that;

Number of moles = Mass/molar mass

mass = 6.37 grams

Molar mass =  58.5 g/mol

Number of moles = 6.37 g/58.5 g/mol

= 0.11 moles

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Calculations:

• Let ,x , represent electron in a body.

• use the following formula tocalculagte excess electrons acquired.

• Charge = 125mC /10000 =1.25 x10^-2

Answer:

correct answer is 0.197 g!

Explanation:

To find the mass of sodium iodide in 50.0 ml of 2.65 x 10^-2 M Nal (aq), you need to first determine the moles of sodium iodide present in the solution. You can do this by using the concentration of the solution and the volume of the solution.

First, convert the concentration of the solution from molarity to moles per liter: 2.65 x 10^-2 M x (1 L/1000 ml) = 2.65 x 10^-5 moles/ml

Next, multiply the moles per milliliter by the volume of the solution in milliliters to find the total number of moles of sodium iodide present: 2.65 x 10^-5 moles/ml x 50.0 ml = 1.325 x 10^-4 moles

Finally, multiply the number of moles of sodium iodide by its molecular weight to find its mass: 1.325 x 10^-4 moles x 149.89 g/mol = 0.197 g. Therefore, the mass of sodium iodide in 50.0 ml of 2.65 x 10^-2 M Nal (aq) is 0.197 g. This means that the correct answer is 0.197 g.

Answer:

Hi, there!

Monoculture is the agricultural practice of growing a single crop, plant, or livestock species, variety, or breed in a field or farming system at a time.

xXxAnimexXx

Have a great day!

Answer:

Explanation:

Xen canh

Answer:

2.28bar

Explanation: Boyle's law P1V1=P2V2 manipulate formula in favor of V2 the new formula should beP1V1/V2

0.895*318/125=2.2768 but to same sigfig it is 2.28

Compound S (C8H16) reacts with one mole of bromine to form a compound with molecular formula C8H16Br2. Its unsaturation is demonstrated by the fact that S decolorizes bromine.

The atomic number 35 and symbol Br are assigned to the chemical element bromine. At room temperature, it is a flammable red-brown liquid that readily evaporates to form a vapour of a similar hue. It is the third-lightest element in group 17 of the periodic table (halogens). Its properties are halfway between those of chlorine and iodine. It was independently discovered by two chemists, Carl Jacob Löwig (1825) and Antoine Jérôme Balard (1826), and was given the name o (bromos), which in Ancient Greek indicates to its pungent and potent smell. The mineral halide salts, which resemble table salt and are white, soluble, and crystalline, contain the element bromine because of its strong reactivity, which prevents it from occurring naturally as a native element. All halogens, including bromine, are actually so reactive that they can only ever form pairs of bonds with other atoms. Despite being very infrequent in the crust of the Earth, the bromide ion (Br) has accumulated in the oceans due to its high solubility.

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250 L of 5.0% w/v glucose solution can be prepared using 125 g of glucose.

w/v = [ mass of solute (g) / volume of solution (mL) ] × 100

5.0 % w/v = [ 125 g / volume of solution (mL) ] × 100

volume of solution (mL) = [ 125 g / 5.0 % w/v ] x 100

volume of solution (mL) = [ 125 g / (5.0 / 100) ] x 100

volume of solution (mL) = [ 125 g / 0.05 ] x 100

Answer:

A logic bomb and a time bomb are both types of malicious software or code that are designed to cause harm to a computer system or network. Here's a brief explanation of each:

Logic Bomb:

A logic bomb is a piece of code or software that is intentionally inserted into a system to execute a malicious action when specific conditions are met. It remains dormant until triggered by a predefined event or circumstance, such as a specific date, time, or user action. Once triggered, the logic bomb may perform various harmful actions, such as deleting files, corrupting data, or disrupting system functionality. The purpose of a logic bomb is often to cause damage or to gain unauthorized access to a system.

Time Bomb:

A time bomb is similar to a logic bomb, but it is specifically designed to activate or execute its malicious payload at a certain date or time. It is usually programmed to remain undetected until the predetermined time arrives. The time bomb can be set to trigger after a specific time period or on a particular date, at which point it may carry out destructive actions. Time bombs can be used by attackers to target specific events or to coordinate an attack to occur simultaneously across multiple systems.

Both logic bombs and time bombs are considered forms of malicious code or malware and are used with malicious intent to disrupt, damage, or compromise computer systems or networks. They can be extremely harmful, and it is important to have strong security measures, such as antivirus software and regular system updates, to protect against such threats.

Explanation:

Answer:

5.0868 x 10 ^12

or 50868 x 10^8

Explanation:

1kg = 1000000mg

answer= 50868 x 10^2 x 1000000

= 50868 x 10^2 x 10^6

= 50868 x 10^8

= 5.0868 x 10^12

The difference between the numbers,

(2.260×104)−(8.098×103) = 598.539.

Subtraction is a mathematic operation. Which is used to remove terms or objects in an expression.

Given:

Two numbers,

(2.260×104) and (8.098×103).

First, we simplify the numbers,

(2.260×104) = 235.04

And  (8.098×103) = 833.579.

The difference between the numbers,

(2.260×104)−(8.098×103) = 833.579 - 235.04.

(2.260×104)−(8.098×103) = 598.539

Therefore, then value is 598.539.

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The water cycle iss a process which helps to circulate and replenish water on earth.

Hydrology is the scientific study of water bodies , the changes that occur in them as well as the various features and behavior of water bodies such as oceans and rivers.

Water circulation created by prevailing wind systems. The Gulf Stream is an example up of the Coriolis effect.

The length of open sea over which wind can blow steadily to create waves is called fetch.

Salinity is the amount of dissolved salt in a liquid

The distance from the crest of one wave to the crest of another is called wavelength

Water circulation created by differences in density deepwater currents

Energy is what moves forward and through a wave.

The cyclical process of the changing state and movement of water around the Earth through evaporation, condensation, and precipitation is called water cycle.

As the amount of salt in water increases, the density of the water increases.

The type of energy possessed by moving water is called kinetic energy.

The rising of ocean water bringing nutrients up from the deep us called upwelling.

Therefore, the water cycle helps to circulate and replenish water on earth.

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The mass percent of oxygen in Nickel(\(III\))sulfate is \(23.68\) percent.

At first, we look up the atomic masses for the element from the periodic table.

The atomic masses are found to be:

Next, we determine how many grams of each element are present in one mole of \(Ni_{2}(SO_{4})_{3}\)

The mass of one mole  \(Ni_{2}(SO_{4})_{3}\) is:

\(117.4g+96g+192g=405.4g\)

So, The mass percent of oxygen \(=(96g/405.4)*100=0.2368*100%\\\)

                                                    \(=23.68 %\) percent.

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Answer:

c i took the test

Explanation:

Daria had some beach sand with her. The sand has a 72 gramme mass. She calculated the volume using the graduated cylinder below. The graduated cylinder contains 15 mL of sand.

The volume of the sand is calculated using the graduated cylinder below. The sand's bulk is specified as 72 grammes.

We can use the water displacement method to calculate the volume of the sand. Following is a description of how to estimate the amount of sand using the water displacement method:

The graduated cylinder of water should first be measured for volume.

The graduated cylinder's water volume should then be measured after adding the sand to it. The volume of water increases by the same amount.

Let's use the provided problem to implement this approach.

In the beginning, there is 10 mL of water in the graduated cylinder. The graduated cylinder contains 25 mL of water once the sand has been added.

The amount of sand is therefore equal to the difference between the two volumes, which is: Sand volume equals final water volume minus initial water volume (25 - 10 = 15 mL).

As a result, there are 15 mL of sand in the graduated cylinder.

Answer : 15

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Answer:The oxygen is coming from the atmosphere.

Explanation:

The density of water is 1.0 grams per milliliter then it will be sink in water

Density is a word we use to describe how much space an object or substance takes up in the volume and in relation to the amount of matter in that object or substance its mass) and another way to put it is that density is the amount of mass per unit of volume

Here given density is 1.0 grams per milliliter and it will be sink in water because the density of water in 1.0 g/ml and this object is more dense than water and the density of an object determines whether it will float or sink in another substance and an object will float if it is less dense than the liquid it is placed in and an object will sink if it is more dense than the liquid it is placed

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