what is the chemistery​

Answer:

[A] = 8.69x10⁻⁵g

Explanation:

Kinetics law of a radioactive atom, A, is:

Ln[A] = -kt + ln[A]₀

Where [A] could be taken as mass of A after time t (In seconds),

k is rate constant = ln2 / Half-Life

[A]₀ is intial mass of A

k = ln2 / 14.9s = 0.04652s⁻¹

Time in seconds:

5min * (60s / 1min) = 300s

Replacing each value:

ln[A] = -0.04652s⁻¹*300s + ln[100.0g]

ln[A] = -9.35

The gas that has a volume of 752 mL at 1.98 atm and 62°C is most likely NO₂ (option D).

The volume of a sample of gas can be calculated using the following formula:

PV = nRT

Where;

According to this question, the volume of a sample of gas (2.49 g) was 752 mL at 1.98 atm and 62°C. The number of moles is as follows:

1.98 × 0.752 = n × 0.0821 × 335

1.489 = 27.5n

n = 0.054mol

molar mass of the gas = 2.49g ÷ 0.054mol = 45.99g/mol

The gaseous substance with the molar mass of 45.99g/mol is NO₂.

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Answer:

the answer is C.

Explanation:

CH4 and 02

Answer:

1. is Molar (with capital M)

2. is molal (m)

Explanation:

By definition, 1 Molar solutions have 1 mol of solute in 1 L of solution and 1 molal solutions have 1 mol of solute in 1 Kg of solvent

Answer:

B)11

Explanation:

The atomic number is the number of protons and electrons in an atom!!

HOPE THIS HELPS!!!!!!

Answer:

,

Explanation:

Refer to pics.............

26.4g is the percentage yield when 20g of aluminium are produced from 50g of aluminium oxide.

The % ratio of the theoretical yield to the actual yield is known as the percent yield. It is calculated as the theoretical yield increased by 100% divided by the experimental yield. The percentage return is 100% if the theoretical and actual yields are equal. Because the real yield is frequently lower than the theoretical value, percent yield is typically lower than 100%.

This may be due to incomplete or conflicting reactions or sample loss during recovery. If the percent yield is more than 100%, more sample than expected was retrieved from the reaction. This may have happened when other reactions took place and the product was also created.

2Al\(_2\)O\(_3\) → 4 Al + 3O\(_2\)

2 mole of Al\(_2\)O\(_3\) =4 mol of Al

2(2×27+48) =4×27

204g of Al\(_2\)O\(_3\)  = 108g of Al

50g of Al\(_2\)O\(_3\) =x

26.4g =x

Therefore, 26.4g is the percentage yield when 20g of aluminium are produced from 50g of aluminium oxide.

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The oil that can be separated at this temperature is canola oil.

The term melting point has to do with the temperature in which a solid can be converted to liquid. This is the temperature at which the various bonds that holds the molecules of the substance can be broken off.

We are told in the question that;  the melting points of canola oil, corn oil, sunflower oil, and peanut oil are 10°C, -11°C, -17°C, and -2°C respectively. We want to know the oil that can be separated easily at  5°C.

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Answer:

This is not chemistry this is physics

Answer:

the two elements are in the same period, with element R the first element in the period and element Q the last element

Answer:

(going down the line)

1. matter

2. hypothesis

3. energy

4. independent variable

5.  theory

6. quantitative data

7. dependent variable

8. constant

9. law

10. qualitative data

Explanation:

The 0.015 moles of gastric acid will be neutralized by a 1.6 gram antacid pill.

By inhibiting the enzyme that produces acid in the stomach to break down food for digestion, antacids neutralize the gastric acid there. An enzyme called pepsin, which breaks down proteins, is inhibited by the antacids, which work by neutralizing the stomach's pH.

0.342 grams of HCL are neutralized every gram of antacid.

Based on the titration's equivalence point expression, this is calculated.

1.6 gram HCL neutralized antacid is,

(0.342 grams HCL to 1 grams antacid) A 1.6 gram antacid

= 0.5472 gram

HCL has a 36.5 gram molar mass.

Moles of HCL = 0.5472 g/36.51 g = 0.01499

As a result, HCL has a mole of 0.015 moles of gastric acid (hci) would it neutralize

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Answer:

See Explanation

Explanation:

The kinetic energy of gas molecules is related to the temperature of the gas because temperature is a measure of the average kinetic energy of the molecules of a gas hence the lower the temperature of the gas the lower the average kinetic energy of the molecules of the gas.

The volume of a given mass of gas is directly proportional its absolute temperature(Charles's law). Hence, as the temperature of the gas gas decreases, the gas volume also decreases.

The number of gas molecules is totally independent of the temperature of the gas hence it stays the same.

As the temperature decreases, the number of collision of gas particles decreases as the kinetic energy of the gas particles decreases.

The pressure of a given mass of gas is related to the movement of gas particles. Hence, the lower the temperature the lower the pressure of the gas. Pressure and temperature are directly related hence pressure decreases as temperature decreases.

Answer:

C₆H₁₈O₉

Explanation:

First we calculate the molar mass of the compound represented by the empirical formula:

Then we divide the given formula mass by the calculated molar mass:

Thus we multiply by 3 the subscripts in the empirical formula:

Taking into account the change of units, 100 meters are 109.361 yards and 328.084 feets.

The rule of three is a way of solving problems of proportionality between three known values and an unknown value, establishing a relationship of proportionality between all of them.

That is, what is intended with it is to find the fourth term of a proportion knowing the other three.  

If the relationship between the magnitudes is direct, that is, when one magnitude increases, so does the other (or when one magnitude decreases, so does the other) , the direct rule of three must be applied.

To solve a direct rule of three, the following formula must be followed, being a, b and c known data and x the variable to be calculated:

a ⇒ b

c ⇒ x

So: \(x=\frac{cxb}{a}\)

The direct rule of three is the rule applied in this case where there is a change of units.

To perform in this case the conversion of units, you must first know that:

Then, you can apply the following rules of three:

1 meter ⇒ 1.09361 yards

100 meters ⇒ x

So: \(x=\frac{100 metersx1.09361 yards}{1 meter}\)

Solving:

x= 109.361 yards

1 meter ⇒ 3.28084 feets

100 meters ⇒ x

So: \(x=\frac{100 metersx3.28084 feets}{1 meter}\)

Solving:

x= 328.084 feets

In summary, 100 meters are 109.361 yards and 328.084 feets.

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The total mass of the reactants equals the total mass of the products the statement about balanced chemical equations is true. Hence, option B is correct.

This is known as the Law of Conservation of Mass, which states that matter can neither be created nor destroyed in a chemical reaction. In other words, the mass of the reactants must equal the mass of the products in a balanced chemical equation.

While the identities of the atoms may change during a reaction, the total number of atoms of each element on both sides of the equation must be the same, thus leading to the conservation of mass.

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Answer:

2 joule

Explanation:

10 gram= 0,01kg

The ball has kinetic enegry

K=1/2 *m *speed²

K=1/2 *0,01 * 400

K=2 Joule

The volume of the solids are found in the attached table.

Volume of a substance refers to the amount of space a given mass of the substance occupies.

Since liquids have no definite volume, the volume of liquids are measured using containers.

Also, the volume of solids can be determined by displacing liquids.

The unit for measuring  the volume of a liquid substance is liters.

Other multiples of the base unit are, mL, cL, dL, daL, hL, kL.

Considering the given volume of substances, the table can be filled as seen in the attachment.

In conclusion, the volume of solids was determined by displacing liquids water.

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Answer:

2 MOLECULES OF WATER

Explanation:

SO, LIQUID

Taking into account the Charles's law, the gas occupies a volume of 0.0182 m³ when the temperature is raised to 95.0 °C. ​

Charles's law shows the relationship between the volume and temperature of a gas sample at constant pressure.

This law states that the volume is directly proportional to the temperature of the gas: if the temperature increases, the volume of the gas increases, while if the temperature of the gas decreases, the volume decreases.

Mathematically, Charles' law is a law that says that when the amount of gas and pressure remain constant, the ratio between volume and temperature will always have the same value:

\(\frac{V}{T}= k\)

Considering an initial state 1 and an initial state 2:

\(\frac{V1}{T1}= \frac{V2}{T2}\)

In  this case, you know:

Replacing in Charles's Law:

\(\frac{0.0141 m^{3} }{284.5 K}=\frac{V2}{368 K}\)

Solving:

\(\frac{0.0141 m^{3} }{284.5 K}x368 K=V2\)

0.0182 m³= V2

Finally, the gas occupies a volume of 0.0182 m³ when the temperature is raised to 95.0 °C. ​

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Answer:

Lower the pH slightly

Explanation:

The mixture of HF, hydrofluoric acid and KF, potassium fluoride produce a buffer that is defined for the equilibrium:

HF(aq) → H⁺(aq) + F⁻(aq)

The buffer can maintain the pH of a solution despite the addition of strong bases or acids.

The reaction of HF with Ca(OH)2 is:

2HF + Ca(OH)2 → 2H2O + CaF2

That means the calcium hydroxide is decreasing the concentration of HF. Based on the equilibrium, the H+ and F- ions will decrease in order to produce more HF. As H+ is decreasing due the equilibrium and not for the addition of a strong base, the pH is decreasing slightly.

There are two characteristics of molecules, one is geometry and other is shape. Shape is excluding lone pair surrounding the central element and geometry is including the lone pair. Therefore, the angle of the given molecule can be found out by VSEPR theory.

VSEPR stands for valence shell electron pair repulsions. VSEPR theory is used to predict the shape and geometry of molecules on the basis of valence electrons pairs that are present around the central element of the molecule.

According to VSEPR theory, Lone pair lone pair repulsion is greater than bond pair bond pair repulsion. There are so many limitations of VSEPR theory. There is a repulsion between bond pair electrons and lone pairs present on the central element.

a) bond angle is 180°

b)bond angle is 120°

c)bond angle is 107.28'

d)bond angle is 109.28'

Therefore, the angle of the given molecule can be found out by VSEPR theory.

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Answer:

From top to bottom of the periodic table ions will increase in radii. However, now left to right the radius is more of a function of the number of electrons. ... Similarly, O2- will be larger than F- as both have 10 electrons but Z=8 for oxygen and Z=9 for fluorine.

The oxygen ion is bigger than the fluorine ion , the reason is explained below

What is an Atomic Structure ?

An atom is composed of electrons , protons and neutrons .

Electrons have negative charge and are grouped in different shells around the nucleus

Protons and neutrons are present in positively charged nucleus

The nucleus has the most mass .The atomic number is the number of protons which is equal to the number of electrons.

Both oxygen atom and fluorine atoms are isoelectronic , they have 10 electrons in the shell , but oxygen has 8 protons while fluorine have 9 protons in the nucleus.

It is believed that as the atomic number increases so the attraction forces of the nuclei increases , making the nucleus smaller and the overall atom smaller

while the oxygen atom on reduction forms oxide anion , which is a dianion and a fluorine atom forms fluoride ion which has a single negative charge and the ion which has more electrons have more electron electron repulsion and the size of the ion is bigger.

Hence the oxygen ion is bigger than the fluorine ion.

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Answer: The value for rate constant for a reaction is \(4.81\times 10^{-4} s^{-1}\)

Explanation:

The integrated rate law equation for first-order kinetics:

\(k=\frac{2.303}{t}\log \frac{a}{a-x}\) ......(1)

Let the initial concentration of reactant be 100 g

Given values:

a = initial concentration of reactant = 100 g

a - x = concentration of reactant left after time 't' = 25 % of a = 25 g

t = time period = 48 min = 2880 s       (Conversion factor: 1 min = 60 s)

Putting values in equation 1:

\(k=\frac{2.303}{2880s}\log (\frac{100}{25})\\\\k=4.81\times 10^{-4} s^{-1}\)

Hence, the value for rate constant for a reaction is \(4.81\times 10^{-4} s^{-1}\)

Answer:  There are three main types of forests: tropical rainforests, deciduous forests, and coniferous forests. Tropical rainforests are found near the equator (the center of Earth), where they are warm all year round.

Explanation:

Ecosystems are defined as a geographical region where biotic factors like animals, plants and microorganisms live together and interact with the abiotic factors.

The three forest ecosystems are temperate, boreal and tropical.

Tropical forest ecosystems have high precipitation and temperature also a high humidity rate. The plant has a twelve-month growing period and the forests are found near the equator regions.

Temperate is found in between the boreal and the tropical forests, it has a high level of rainfall and humid conditions and is covered with the deciduous type of trees.

Boreal or the taiga forest ecosystems are located in the subarctic regions with low temperatures and have long winters. They are covered majorly by the scale-leaved evergreen and the needle leaves cones.

All three forest ecosystems have great species diversity, the tropical and the temperate forest have dense vegetation and the temperate and boreal have evergreen forests.

Therefore, three forest ecosystems are temperate, boreal and tropical.

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When two or more substances are together in the same place but are not chemically combined they form a mixture.

The word mixture is used in chemistry to denote a combination of two or more elements that conserve their original properties, which is fundamental to achieving the separation of such elements in the future.

Therefore, with this data, we can see that a mixture is a mix or combination of two or more elements that still conserve their physical and chemical properties, thereby allowing their separation through different techniques.

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Explanation:

kinetic energy?? idek hope I helped in anyway possible

Answer:

7.5 joules also 7.5 J

Explanation:

Answer:

B attract

Explanation:

There will be statication