HELP PLEASE What about winter temperatures of 0 and -3? …………….% 28 and 15? ……………….%

Answer:

(D.) Nitrifiers are bacteria that generate nitrites or nitrates.

Explanation:

In the nitrogen cycle which occurs in nature, ammonia and ammonium compounds in the soil from organic sources and are converted to nitrites and nitrates by aerobic microorganisms.

Nitrifiers, as the name implies, are these such aerobic bacteria which oxidize inorganic constituents in the soil to generate energy. Examples of these nitrifiers are nitrobacter and nitrosomonas.

Answer:

10grams

Explanation:

So it weighs 236 grams added with 25 grams. So it now weighs 261 grams so 10 grams of sugar remains in it.

Final answer:

Michelle added 10 grams of sugar to her coffee. The calculation involved subtracting the initial coffee weight and the weight of added milk from the final mixture weight.

Explanation:

To determine how many grams of sugar Michelle added to her coffee, we need to analyze the before and after weights of the mixture. The initial weight of the coffee was 236 grams, and after adding milk, the total weight became 271 grams. Given that Michelle also added 25 grams of milk, we can calculate the weight of the sugar.

The calculation to find the weight of the sugar added is as follows:

Subtract the initial weight of the coffee (236 grams) from the final weight of the mixture (271 grams) to account for the added ingredients: 271 grams - 236 grams = 35 grams.

Subtract the weight of the milk (25 grams) from the 35 grams to find the weight of the sugar: 35 grams - 25 grams = 10 grams.

Therefore, Michelle added 10 grams of sugar to her coffee.

Answer:

3041.5L

Explanation:

Data obtained from the question include:

V1 (initial volume) = 2785 L

P1 (initial pressure) = 830mmHg

P2 (final pressure) = stp = 760mmHg

V2 (final volume) =?

Applying the Boyle's law equation P1V1 = P2V2, the final volume propane can be achieved by as illustrated below:

P1V1 = P2V2

830 x 2785 = 760 x V2

Divide both side by 760

V2 = (830 x 2785)/760

V2 = 3041.5L

Therefore, the volume of the propane at standard pressure is 3041.5L

By applying Boyle's Law and using the given initial conditions, the volume of propane at standard pressure is calculated to be 3041.71 L.

The question involves applying the gas law to determine the volume of propane at standard pressure. The given conditions are 2785 L of propane at 830 mmHg, and we need to find the volume at standard pressure (760 mmHg). Using Boyle's Law, which states that P1V1 = P2V2 where P is pressure and V is volume, we can calculate the new volume at standard pressure.

First, convert the initial pressure to the same units as the standard pressure, which is already in mmHg. Then, set up the equation with P1 = 830 mmHg, V1 = 2785 L, P2 = 760 mmHg, and solve for V2:

V2 = (P1 × V1) / P2 = (830 mmHg × 2785 L) / 760 mmHg

V2 = 3041.71 L

So, the volume of propane at standard pressure is 3041.71 L.

Answer :  The wavelength of yellow light produced by a sodium lamp is, [tex]8.98\times 10^{-7}m[/tex]

Explanation : Given,

Frequency of radiation = [tex]3.34\times 10^{14}Hz=3.34\times 10^{14}s^{-1}[/tex]

conversion used : [tex]Hz=s^{-1}[/tex]

Formula used :

[tex]\nu=\frac{c}{\lambda}[/tex]

where,

[tex]\nu[/tex] = frequency of radiation

[tex]\lambda[/tex] = wavelength of radiation

c = speed of light = [tex]3\times 10^8m/s[/tex]

Now put all the given values in the above formula, we get:

[tex]3.34\times 10^{14}s^{-1}=\frac{3\times 10^8m/s}{\lambda}[/tex]

[tex]\lambda=8.98\times 10^{-7}m[/tex]

Therefore, the wavelength of yellow light produced by a sodium lamp is, [tex]8.98\times 10^{-7}m[/tex]

The percentage by mass of sodium in sodium hydrogen carbonate (NaHCO3) is 27.4%, calculated by dividing the atomic mass of sodium by the molar mass of NaHCO3 and multiplying by 100%.

To calculate the percentage by mass of sodium (Na) in a unit of sodium hydrogen carbonate (NaHCO3), you first need to know the atomic masses of the elements involved. The atomic mass of Na is approximately 23 g/mol, H is about 1 g/mol, C is approximately 12 g/mol and O is approximately 16 g/mol.

Using these numbers, the molar mass of NaHCO3 is about 84 g/mol (23 for Na, 1 for H, 12 for C, and 48 for the three O atoms). To find the percentage of Na in NaHCO3, divide the atomic mass of Na by the molar mass of NaHCO3 and multiply by 100%:

(23 g/mol ÷ 84 g/mol) x 100% = 27.4%.

Therefore, the percentage by mass of sodium in a formula unit of sodium hydrogen carbonate is 27.4%.

https://brainly.com/question/35598615

#SPJ3

The mass percentage of sodium (Na) in a formula unit of sodium hydrogen carbonate (NaHCO₃) is 27.36%. The calculated molar mass of NaHCO₃ is 84.01 g/mol.

To determine the percentage by mass of sodium (Na) in a formula unit of sodium hydrogen carbonate (NaHCO₃), we need to follow these steps:

1. Find the atomic masses of each element:

 Sodium (Na) = 22.99 g/mol

 Hydrogen (H) = 1.01 g/mol

 Carbon (C) = 12.01 g/mol

 Oxygen (O) = 16.00 g/mol

2. Calculate the molar mass of NaHCO₃:

         NaHCO₃ = 22.99 g/mol (Na) + 1.01 g/mol (H) + 12.01 g/mol (C) + 3 x 16.00 g/mol (O)

         NaHCO₃ = 22.99 + 1.01 + 12.01 + 48.00 = 84.01 g/mol

3. Determine the mass percentage of sodium (Na):

          Mass % Na = (22.99 g / 84.01 g) x 100

          Mass % Na = 27.36%

Therefore, the mass percentage of sodium (Na) in sodium hydrogen carbonate (NaHCO₃) is 27.36%.

Answer:

1.0 *10^(-4) mol

Explanation:

For gases:

n1/n2 = V1/V2

n1/3.8*10^(-4) mol = 230 mL/ 860 mL

n1 = 3.8*10^(-4)*230/860 = 1.0 *10^(-4) mol

A balloon containing gas expands from 230 mL to 860 mL as more helium is added. 1.0 × 10⁻⁴ mole was the initial quantity of helium present if the expanded balloon contains 3.8 × 10⁻⁴ mole assuming constant temperature and pressure.

The ideal gas law states that the pressure of gas is directly proportional to the volume and temperature of the gas.

PV = nRT

where,

P = Pressure

V = Volume

n = number of moles  

R = Ideal gas constant

T = Temperature

Now, calculating the ratio between the initial and the final numbers of moles of gas

PV = nRT

or, [tex]\frac{V}{n} = \frac{(RT)}{P}[/tex]

or, [tex]\frac{V}{n} = k[/tex]

or, [tex]\frac{V_1}{n_1} = \frac{V_2}{n_2}[/tex]

or, [tex]\frac{n_1}{n_2} = \frac{V_1}{V_2}[/tex]        [Avogadro's Law]

Here, Volume and number of moles are the variables which are known.

Now put the values in above formula we get

⇒ [tex]\frac{n_1}{n_2} = \frac{V_1}{V_2}[/tex]

⇒ [tex]\frac{n_1}{3.8 \times 10^{-4}} = \frac{230}{860}[/tex]

⇒ [tex]n_{1} = \frac{3.8 \times 10^{-4} \times 230}{860}[/tex]

⇒ n₁ = 1.0 × 10⁻⁴ mole

Thus, we can say that 1.0 × 10⁻⁴ mole was the initial quantity of helium present if the expanded balloon contains 3.8 × 10⁻⁴ mole assuming constant temperature and pressure. Volume and number of moles are the variables which are known.

Learn more about the Ideal Gas here: https://brainly.com/question/1063475

#SPJ2

Once upon a time there was a lovely

                        princess. But she had an enchantment

                        upon her of a fearful sort which could

                        only be broken by love's first kiss.

                        She was locked away in a castle guarded

                        by a terrible fire-breathing dragon.

                        Many brave knights had attempted to

                        free her from this dreadful prison,

                        but non prevailed. She waited in the

                        dragon's keep in the highest room of

                        the tallest tower for her true love

                        and true love's first kiss. (laughs)

                        Like that's ever gonna happen. What

                        a load of - (toilet flush)

              Allstar - by Smashmouth begins to play. Shrek goes about his

              day. While in a nearby town, the villagers get together to go

              after the ogre.

Answer:

The volume of the gas when  pressure decreases to 620 mmHg is 2.52 L

Explanation:

Boyle's law is a law related to gases that establish a relationship between the pressure and the volume of a given amount of gas, without variations in temperature, that is, at constant temperature. So, this law establishes that at constant temperature, the volume of a fixed mass of gas is inversely proportional to the pressure it exerts.

Boyle's law is expressed mathematically as:

Pressure * Volume = constant

o P * V = k

Having a certain volume of gas V1 that is at a pressure P1 at the beginning of the experiment, if you vary the volume of gas to a new value V2, then the pressure will change to P2, and it will be true:

P1 * V1 = P2 * V2

In this case:

Replacing:

780 mmHg* 2 L= 620 mmHg* V2

Solving:

[tex]V2=\frac{780 mmHg* 2L}{620 mmHg}[/tex]

V2= 2.52 L

The volume of the gas when  pressure decreases to 620 mmHg is 2.52 L

Answer:

2.52 L

Explanation:

Step 1:

The following data were obtained from the question:

Initial pressure (P1) = 780 mmHg

Initial volume (V1) = 2.0 L.

Final pressure (P2) = 620 mmHg.

Final volume (V2) =?

Step 2:

Determination of the final volume of the gas.

From the question given, we discovered that the temperature is constant. Since the temperature is constant, the gas is simply obeying Boyle's law.

Applying the Boyle's law equation, the final volume of the gas can be obtained as follow:

P1V1 = P2V2

780 x 2 = 620 x V2

Divide both side by 620

V2 = (780 x 2) /620

V2 = 2.52 L

Therefore, the volume of the gas when the pressure decreases to 620 mmHg is 2.52 L

Answer:

B

Explanation:

GOOD LUCK!!!

Answer:

The water vapor in the air releases energy to the cold water in the glass causing

the vapor to become liquid that collects on the sides of the glass.

Explanation:

Matter exist in solid, liquid and gaseous states. The energy of particles constituting each state of matter differs. In the gaseous state, the particles that compose matter are highly energetic and move at high speeds. Liquid particles possess lower energy and solid particles are the least energetic.

When water vapour in air comes in contact with a cold glass of water, heat exchange occurs. The energetic gas particles of water vapour looses energy to the cold water particles. This causes the water vapour outside the glass to condense to liquid and collects outside the glass.

The best explanation for water droplets collecting on the outside of a cold glass of water on a hot summer day is: Option (1.)The water vapor in the air releases energy to the cold water in the glass causing the vapor to become liquid that collects on the sides of the glass.

This process is called condensation.

On a hot day, the air is typically humid, meaning it contains a significant amount of water vapor. When the humid air comes into contact with the cold surface of the glass, the temperature of the air near the glass drops. If this temperature drops below the dew point (the temperature at which air becomes saturated with moisture), the water vapor in the air condenses into liquid water. This is because the cold surface of the glass absorbs heat from the water vapor, causing the vapor to lose energy and change from a gaseous state to a liquid state, forming droplets on the outside of the glass.

Answer:

Partial pressure O₂ = 1.49 atm

Explanation:

We can solve this, by the mole fraction concept.

Mole fraction = Moles of gas / Total moles

We can also define mole fraction as: Partial pressure of a gas / Total pressure

Total moles = Moles of O₂ + Moles of N₂

36.5 g. 1 mol / 32g + 46.4 g . 1mol /28g = 2.79 moles

1.14 moles O₂ + 1.65 moles N₂ = 2.79 moles

Partial pressure O₂ / Total pressure = Moles of O₂ / Total moles

Partial pressure O₂ = (Moles of O₂ / Total moles) . Total pressure.

We replace: (1.14 mol / 2.79 mol) . 3.64 atm = 1.49 atm

Partial pressure O₂ = 1.49 atm

Answer:

The answer to your question is   P2 = 2676.6 kPa

Explanation:

Data

Volume 1 = V1 = 12.8 L                        Volume 2 = V2 = 855 ml

Temperature 1 = T1 = -108°C               Temperature 2 = 22°C

Pressure 1 = P1 = 100 kPa                    Pressure 2 = P2 =  ?

Process

- To solve this problem use the Combined gas law.

                     P1V1/T1 = P2V2/T2

-Solve for P2

                     P2 = P1V1T2 / T1V2

- Convert temperature to °K

T1 = -108 + 273 = 165°K

T2 = 22 + 273 = 295°K

- Convert volume 2 to liters

                       1000 ml -------------------- 1 l

                         855 ml --------------------  x

                         x = (855 x 1) / 1000

                         x = 0.855 l

-Substitution

                    P2 = (12.8 x 100 x 295) / (165 x 0.855)

-Simplification

                    P2 = 377600 / 141.075

-Result

                   P2 = 2676.6 kPa

Answer:

Check all of them

Explanation:

All are correct.

- stong electrolytes dissolve completely

- weak disolve partially

- nonelectrolytes do not dissolve

Answer:

Explanation:

Answer:

91.64L

Explanation:

Step 1:

Data obtained from the question.

This includes the following:

Initial volume (V1) = 43L

Initial pressure (P1) = 1.3 atm

Final volume (V2) =..?

Final pressure (P2) = 0.61 atm

Step 2:

Determination of the final volume.

To solve for the final volume, we'll apply the Boyle's law equation since the temperature is constant. The final volume is obtained as follow:

P1V1 = P2V2

1.3 x 43 = 0.61 x V2

Divide both side by 0.61

V2 = (1.3 x 43)/0.61

V2 = 91.64L

Therefore, the new volume is 91.64L

The volume will be 91.64 L when the pressure is 0.61 atm

From Boyle's law equation, we have that

P₁V₁ = P₂V₂

Where P₁ is the initial pressure

V₁ is the initial volume

P₂ is the final pressure

and V₂ is the final volume

From the given information

P₁ = 1.3 atm

V₁ = 43 L

P₂ = 0.61 atm

V₂ = ?

Putting the parameters into the formula, we get

1.3 × 43 = 0.61 × V₂

∴ [tex]V_{2} = \frac{1.3 \times 43}{0.61}[/tex]

V₂ = 91.64 L

Hence, when the pressure is 0.61 atm, the volume will be 91.64 L

Learn more here: https://brainly.com/question/20277275

Answer:

C. ΔG is positive at low temperatures, but negative at high temperatures (and zero at some temperature).

Explanation:

Since we need to give energy in the form of heat to vaporize a liquid, the enthalpy is positive. In a gas, molecules are more separated than in a liquid, therefore the entropy is positive as well.

Considering the Gibbs free energy equation:

ΔG= ΔH - TΔS

          +        +

When both the enthalpy and entropy are positive, the reaction proceeds spontaneously (ΔG is negative) at high temperatures. At low temperatures, the reaction is spontaneous in the reverse direction (ΔG is positive).

Answer:

d

Explanation:

Carbohydrates are compounds containing carbon, hydrogen, and oxygen. Therefore, a is true.

An empirical formula is the simplest ratio of atoms present in a compound. Therefore, C2H4O2 and C3H6O3, (if you simplified them like you would a fraction) would be CH2O. Therefore b is correct,

They also have the same % composition, with a ratio of 1 carbon : 2 hydrogen : 1 oxygen. Therefore, c is correct.

Since a, b and c are all correct, the answer is d, all of the above are true.

Final answer:

Methanol, ethanoic acid, and glucose all share the same empirical formula CH2O, despite having different molecular structures and functions.

Explanation:

What methanol (CH2O), ethanoic acid (C2H4O2), and glucose (C6H12O6) all have in common is that they all have the same empirical formula, which is CH2O. This simplified empirical formula indicates a molar ratio between carbon, hydrogen, and oxygen, which is 1:2:1. However, these compounds have different molecular formulas, meaning they contain different numbers of atoms, but when simplified to the lowest whole number ratio, they share the same empirical formula.

Methanol, a simple alcohol with the molecular formula CH4O, ethanoic acid (also known as acetic acid, found in vinegar), with a molecular formula of C2H4O2, and glucose, a simple sugar with the molecular formula C6H12O6, while all different compounds, share the empirical formula CH2O. This showcases an interesting aspect of organic chemistry where different compounds can have identical empirical formulas but vary greatly in structure and function.

Answer:

Shivering.

Explanation:

Homeostasis is the bodies need to keep things at a normal. When you are cold you shiver to produce body heat and get back to normal  

Answer:

Explanation:

stoichiometry is used in cooking because it helps you determine the amount or proportion of compounds you will need in a chemical reaction. Stoichiometry is present in daily life, even in the cooking recipes we make at home. The reactions depend on the compounds involved and how much of each compound is needed to determine the product that will result.

Answer:

Ammonia

Explanation:

Answer:

ammonia NH3

Explanation:

pls mark brainliest

Answer:

C)No; the rate law must be determined experimentally.

Explanation:

Rate Laws are empirical relationships defining rates of reaction. For any given reaction The Empirical Rate Law is the product of the concentration of the reactants raised to the power of their order of reaction. That is, for the hypothetical reaction aA + bB => Products its Empirical Rate Law is ...

Rate = k[A]ᵃ[B]ᵇ where k = the rate constant and a & b are orders of reaction.

Order of reaction is a 'rate trend' when one changes a rate factor such as concentration. This can only be determined by experimental observation by physically increasing or decreasing concentration and observing the change in reaction rate relative to a reference reaction of interest. Typically they are whole numbers but can be decimal fractions.  

By graphing experimental outcomes of Rxn Rate vs Change in Concentration one can define the order of reaction. Observations  give ...

0-order reactions => change concentration => no change in rate

1st order reactions => change concentration => proportional linear change in rate

2nd order reactions => change concentration => exponential change in rate.        

Answer:

The answer is C

Explanation:

I had the question on edg

Answer:

.

Explanation:

Eardrum or tympanic membrane changes sound to vibration and pass through malleus, incus and stapes.

Answer:

[tex]P_{2} = 3.259\,atm[/tex]

Explanation:

Let suppose that air inside the tire behaves ideally. The equation of state for ideal gases is:

[tex]P\cdot V = n\cdot R_{u}\cdot T[/tex]

As tire can be modelled as a closed and rigid container, there are no changes in volume and number of moles. Hence, the following relationship is constructed:

[tex]\frac{P_{1}}{T_{1}} = \frac{P_{2}}{T_{2}}[/tex]

The final pressure is:

[tex]P_{2} = \frac{T_{2}}{T_{1}}\cdot P_{1}[/tex]

[tex]P_{2} = \frac{298.15\,K}{278.15\,K}\cdot (3.04\,atm)[/tex]

[tex]P_{2} = 3.259\,atm[/tex]

Answer:

P2=3,26 atm

Explanation:

Considering that this gas behaves like an ideal gas, the equation used in noble gases is:

PxV = nxrxT

p is pressure, v is volume, n is number of moles, r is a constant of noble gases whose value is 0.082x10exp23 as long as you use it in the equations it has the same value (that is why it is called constant) and t would be the temperature.

Because v, r and n are values that did not change throughout the reaction of the gas, we are only going to take into account the p and t that did change throughout the reaction and that is why there is an initial and final pressure and a final and initial temperature.

So:

P1 / T1 = P2 / T2 (where value 1 refers to start, and 2 to end)

Regarding this equation, since we want to know the value of P2, which is the FINAL pressure of the gas, that is, what pressure did it achieve with the reaction, the equation that we would use would be solving for P2:

P2 = (T2 / T1) xP1 = 3.26 atm

Answer:

596 g of CO₂ is the mass formed

Explanation:

Combustion reaction:

C₂H₄(g) + 3O₂(g) → 2CO₂(g) + 2H₂O(g)

We determine moles of ethylene that has reacted:

189.6 g . 1mol / 28g = 6.77 moles

We assume the oxygen is in excess so the limiting reagent will be the ethylene.

1 mol of ethylene produce 2 moles of CO₂ then,

6.77 moles will produce the double of CO₂, 13.5 moles.

We convert the moles to mass: 13.5 mol . 44 g /1mol = 596 g

Answer:

Explanation:

[tex]C_{2}H_{4}O_{2}+2O_{2}[/tex] → [tex]2CO_{2}+2H_{2}O[/tex]

The balanced chemical equation is C₂H₄O₂ + (3/2)O₂ → 2CO₂ + 2H₂O.

A balanced chemical equation is an equation that represents a chemical reaction with an equal number of atoms of each element on both sides of the equation. It follows the law of conservation of mass, which states that matter cannot be created or destroyed during a chemical reaction.

In a balanced chemical equation, the coefficients are used to adjust the number of molecules or atoms involved in the reaction. Balancing chemical equations is essential for accurately representing the stoichiometry of a reaction and understanding the ratios of reactants and products involved.

Learn more about chemical equations, here:

https://brainly.com/question/29130807

#SPJ2

Answer:

Total pressure increased

Explanation:

When gas C is added in the vessel then number of mole increases and number of collision depends on the number of molecules present in the vessel and on adding gas C ,mole also increases hence number of collision increases therefore pressure also increases because number of collision increases.

Total pressure increases.

The initial temperature (T₁) was 263.0145 K.

Given Conditions:

Final volume (V₂) = 10.0 L

Final temperature (T₂) = 25.0°C = 298.15 K

Final pressure (P₂) = 1.00 atm

Initial volume (V₁) = 9.40 L

Initial pressure (P₁) = 0.939 atm

Using the Combined Gas Law:

[tex]\[ \dfrac{P_1 \times V_1}{T_1} = \dfrac{P_2 \times V_2}{T_2} \][/tex]

Rearrange to Solve for T₁:

[tex]\[ T_1 = \dfrac{P_1 \times V_1 \times T_2}{P_2 \times V_2} \][/tex]

Plugging in the Values:

[tex]\[ T_1 = \dfrac{0.939 \, \text{atm} \times 9.40 \, \text{L} \times 298.15 \, \text{K}}{1.00 \, \text{atm} \times 10.0 \, \text{L}} \][/tex]

Calculate T₁:

[tex]\[ T_1= \dfrac{2630.145}{10} = 263.0145 \, \text{K} \][/tex]

Answer:

89.57 %

Explanation:

Don't have one just thought id help <3

Answer: 89.6

Explanation:

Answer:

72.028g

Explanation:

Data obtained from the question. This includes:

Volume (V) = 25.7 L

Temperature (T) = –22.2°C

Pressure (P) = 997 mmHg

Mass of CO2 =..?

Mass of CO2 can be obtained as follow:

Step 1:

Conversion to appropriate unit:

It is important to express each variables in their appropriate units in order to obtain the desired result in the right unit.

For temperature:

We shall be converting from celsius to Kelvin. This is illustrated below:

Temperature (Kelvin) = temperature (celsius) + 263

temperature (celsius) = –22.2°C

Temperature (Kelvin) = –22.2°C + 263

Temperature (Kelvin) = 250.8K

For Pressure:

We shall be converting from mmHg to atm. This is illustrated below:

760mmHg = 1 atm

Therefore, 997 mmHg = 997/760 = 1.31 atm

Step 2:

Determination of the number of mole of CO2.

With the ideal gas equation, we can obtain the number of mole of CO2 as follow:

Volume (V) = 25.7 L

Temperature (T) = 250.8K

Pressure (P) = 1.31 atm

Gas constant (R) = 0.082atm.L/Kmol

Number of mole (n) =...?

PV = nRT

n = PV/RT

n = (1.31 x 25.7)/(0.082 x 250.8)

n = 1.637 mole

Step 3:

Converting 1.637 mole of CO2 to grams. This is illustrated below:

Number of mole of CO2 = 1.637 mole

Molar Mass of CO2 = 12 + (2x16) = 12 + 32 = 44g/mol

Mass of CO2 =...?

Mass = number of mole x molar Mass

Mass of CO2 = 1.637 x 44

Mass of CO2 = 72.028g.

Answer:

255.51cm3

Explanation:

Data obtained from the question include:

V1 (initial volume) =?

T1 (initial temperature) = 50°C = 50 + 273 = 323K

T2 (final temperature) = - 5°C = - 5 + 237 = 268K

V2 (final volume) = 212cm3

Using the Charles' law equation V1/T1 = V2/T2, the initial volume of the gas can be obtained as follow:

V1/T1 = V2/T2

V1/323 = 212/268

Cross multiply to express in linear form

V1 x 268 = 323 x 212

Divide both side by 268

V1 = (323 x 212)/268

V1 = 255.51cm3

Therefore, the initial volume of the gas is 255.51cm3

Answer:

Explanation:

To get the initial volume of the hydrogen in cm³, we apply the equation generated from Charles' law.

V1/T1=V2/T2

Where;

V1=initial volume of gas

T1=initial temperature of gas

V2=final volume of gas

T2=final temperature of gas

We make V1 subject of formula

V1=(V2×T1)/T2

Given;

V2=212cm³

T1=50°C=(50+273)K=323K

T2=-5.0°C=(-5.0+273)K=268K

V1=(212×323)/268

V1=255.5cm³

Therefore, the initial volume of the hydrogen was 255.5cm³