1.
How many kJ are required to completely vaporize a 250 gram sample of water at 100°C?
general formula

Answer:

Molecular formula of the compound = H₂CO₃

Explanation:

First, the empirical formula of the compound is determined

Percentage by mass of each element is given as shown below:

H = 3.3% ; C = 19.9%; O = 77.4%

Mole ratio of the elements= percentage mass/ molar mass

H = 3.3/ 1 = 3.3

C = 19.3/12 = 1.6

O = 77.4/16 = 4.8

whole number ratio is obtained by dividing through with the smallest ratio

H = 3.3/1.6; C = 1.6/1.6; O = 4.8/1.6

H : C : O = 2 : 1 : 3

Empirical formula = H₂CO₃

Molecular formula/mass = n(empirical formula/mass)

60 = n(2*1 + 12*1 + 16*3)

60 = n(62)

n = 60/62 = 0.96

n is approximately = 1

Therefore, molecular formula of the compound = (H₂CO₃) * 1

Molecular formula of the compound = H₂CO₃

The molecular formula of a compound composed of 3.3% H, 19.3% C, and 77.4% O and a molar mass of approximately 60 g/mol is CH2O3.

HOW TO CALCULATE MOLECULAR FORMULA:

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Answer:

D

Explanation:

because the higher the wavelength the shorter the pitch and the shorter the wavelength the higher the pitch

We know, when temperature and pressure is constant :

[tex]\dfrac{V_1}{n_1}=\dfrac{V_2}{n_2}[/tex]      ....1)

[tex]n_1 = 3\ moles,\ V_1 = 1.50\ L[/tex]

[tex]n_2 = 3 + 0.80 = 3.80 \ moles[/tex]

Let, final volume is [tex]V_2[/tex].

Putting all values in equation 1), we get :

[tex]\dfrac{V_1}{n_1}=\dfrac{V_2}{n_2}\\\\\dfrac{1.50}{3}=\dfrac{V_2}{3.80}\\\\V_2 = \dfrac{1.50\times 3.80}{3}\\\\V_2 = 1.9\ L[/tex]

Therefore, volume (in L) of the balloon if 0.80 moles of gas are added is 1.9 L.

Hence, this is the required solution.

Answer:

I believe it is "in industrialized areas"

Explanation:

According to Calvert Academy it says "Only 25% of the world's population lives in industrial areas. Hope this helps :)

Answer:

i podwmk

Explanation:

Concepts used:

1 mole of an element or a compound has 6.022 * 10²³ formula units

So, we can say that: Number of formula units = number of moles * 6.022*10²³

number of moles of an element or a compound = given mass/molar mass

__________________________________________________________

003 - Number of CaH₂ formula units in 6.065 grams

Number of Moles:

We know that the molar mass of CaH₂ is 42 grams/mol

Number of Moles of CaH₂ = given mass/molar mass

Number of moles = 6.065 / 42

Number of moles = 0.143 moles

Number of Formula units:

Number of formula units = number of moles * 6.022*10²³

= 0.143 * 6.022 * 10²³

= 0.86 * 10²³ formula units

__________________________________________________________

004 - Mass of 6.34 * 10²⁴ formula units of NaBF₄

Number of Moles:

We mentioned this formula before:

Number of formula units = number of moles * 6.022*10²³

Solving it for number of moles, we get:

Number of moles = Number of Formula units / 6.022* 10²³

replacing the variable

Number of moles = 6.34 * 10²⁴ / 6.022*10²³

Number of moles=  10.5 moles

Mass of 10.5 moles of NaBF₄:

Molar mass of NaBF₄ = 38 grams/mol

Mass of 10.5 moles = 10.5 * molar mass

Mass of 10.5 moles = 10.5 * 38

Mass = 399 grams

__________________________________________________________

005 - Number of moles in 9.78 * 10²¹ formula units of CeI₃

Number of Moles:

We have the formula:

Number of moles = Number of Formula units / 6.022* 10²³

replacing the variables

Number of Moles = 9.78 * 10²¹ / 6.022*10²³

Number of Moles = 1.6 / 10²

Number of Moles = 1.6 * 10⁻² moles   OR   0.016 moles

Answer:

241.08039999999588

Explanation:

Answer:

alkali metal

Explanation:

The alkali metals in period 4 will have the lowest ionization energy of the elements in the period.

Across a period ionization energy increases progressively from left to right due to decreasing atomic radii caused by the increasing nuclear charge which is not compensated for by successive electronic shells.

Down a group, it decreases.

The periodic table is the arrangement of the elements based on the atomic numbers. The elements of the alkali period have the lowest ionization energy.

Ionization energy or the potential is the amount of the potential needed by the molecule or the atom to remove the electron from their shells. The alkali metal elements have the lowest ionization energy.

The ionization potential of the elements increases from the left towards the right of the period due to the decrease in the atomic radii and decreases from top to bottom in a group.

In the period from left to right the atomic radius of the atoms decreases due to the increase in the nuclear charge of the atoms.

Therefore, option B. alkali metal has the lowest ionization energy.

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Answer:

2.43 moles of water are required.

Explanation:

Given data:

Moles of H₂O required = ?

Moles of NO₂ present = 7.30 mol

Chemical equation:

3NO₂+ H₂O  →     NO + 2HNO₃

Now we will compare the moles of NO₂ and H₂O.

                    NO₂       :           H₂O

                      3          :              1

                   7.30        :          1/3×7.30 = 2.43 mol

Answer:

52.9 KJmol-1

Explanation:

From;

log(k2/k1) = Ea/2.303 * R (1/T1 - 1/T2)

The temperatures must be converted to Kelvin;

T1 = 25° C + 273 = 298 K

T2= 35°C + 273 = 308 K

R= gas constant = 8.314 JK-1mol-1

Substituting values;

log 2 = Ea/2.303 * 8.314 (1/298 - 1/308)

Ea = 52.9 KJmol-1

Answer:

the process of growth or increase, typically by the gradual accumulation of additional layers or matter.

Explanation:

Answer:

The process of growth or increase, typically by the gradual accumulation of additional layers or matter.

Explanation:

[tex]\mathfrak{\huge{\pink{\underline{\underline{AnSwEr:-}}}}}[/tex]

Actually Welcome to the Concept of the Kinematics.

Here, we know that, Velocity = Distance / Time,

So here, Distance = 10km = 10×1000 = 10000 metres.

, Time = 14 min 30 sec = 870 seconds,

so now, we get velocity as,

=> V = 10000 ÷ 870 => 11.49 m/s .

Hence, Velocity is 11.49 m/s.

Answer:

longer/less

Explanation:

In moving from left to right on the electromagnetic diagram, the wavelength becomes longer and the energy lessens.

The electromagnetic diagram presents a spectrum of radiation.

Answer:

6 mol H₂O

General Formulas and Concepts:

Chemistry

Explanation:

Step 1: Define

RxN:     2H₂ + O₂ → 2H₂O

Given:   3 moles O₂

Step 2: Stoichiometry

[tex]3 \ mol \ O_2(\frac{2 \ mol \ H_2O}{1 \ mol \ O_2} )[/tex] = 6 mol H₂O

Step 3: Check

We are given 1 sig fig.

Our final answer has 1 sig fig, so no need to round.

Answer:

The specific  heat  capacity  of  unknown  metal  is  calculated  using the  following  formula

Q=MC  delta  T  where

Q= heat(862 j)

M=  mass  (17 g)

C=  specific  heat capacity=?

delta T = change in  temperature  (  35-10= 25 c)

by making  C the  subject  of the  formula  C=Q/m  delta T

=  862 j/( 17 g  x25 c) = 2.028 j/g/c

Explanation:

Answer:

5m/s²

Explanation:

Given parameters:

Initial velocity  = 10m/s due east

Final velocity  = 30m/s due east

Time = 4s

Unknown:

Acceleration of the car = ?

Solution:

Acceleration is the rate of change of velocity with time.

Mathematically;

 Acceleration  = [tex]\frac{v - u}{t}[/tex]  

v is the final velocity

u is the initial velocity

t is the time taken

  Insert the parameters and solve;

  Acceleration  = [tex]\frac{30 - 10}{4}[/tex]   = 5m/s²

Answer:

Lithium and Sodium

Explanation:

Answer:

[tex]M=0.173M[/tex]

Explanation:

Hello!

In this case, since the molarity of a solution is defined in terms of the moles of solute divided by the volume of the solution in liters and has units of mol/L or M:

[tex]M=\frac{n}{V}[/tex]

For the solute, Fe3Br2, which has a molar mass of 327.3430 g/mol, the moles in 42.389 g are:

[tex]n=42.389g*\frac{1mol}{327.3430g} =0.12949mol[/tex]

Thus, since the volume in liters is 0.750 L from those given 750 mL, the molarity turns out:

[tex]M=\frac{0.12949mol}{0.750L}\\\\M=0.173M[/tex]

Best regards!

Answer: Where is the folowing?

Explanation:

Answer:

Percentage of HCL = 37.11 % (Approx)

Molarity = 16.17 m (Approx)

Explanation:

Given:

Molarity = 12.0 M  of hcl

Density = 1.18 g/ml

Computation:

1L of hcl solution contains = 12 moles

Mass = Moles x Molar mass

Mass of HCl = 12 x 36.5

Mass of HCl  = 438 g  = 0.438 kg

Mass of 1 L solution =  1.18 x 1,000 ml

Mass of 1 L solution = 1180 g

Percentage of HCL = [438/1180]100

Percentage of HCL = 37.11 % (Approx)

Molarity = 12 / [1.18 - 0.438]

Molarity = 12 / [0.742]

Molarity = 16.17 m (Approx)

Answer:

[tex]V_2=1.80L[/tex]

Explanation:

Hello!

In this case, since in this problem we can see that the volume, pressure and temperature are changing, considering that the vapor pressure of water at 0 °C or also 273 K is 0.006 atm, the pressure of dry hydrogen would be 0.99 atm, thus, we can write:

[tex]\frac{P_1V_1}{T_1} =\frac{P_2V_2}{T_2}[/tex]

Now, as we need the final volume V2, by solving for it, we write:

[tex]V_2=\frac{P_1V_1T_2}{T_1P_2}[/tex]

In such a way, we plug in the given data to obtain:

[tex]V_2=\frac{0.97atm*2.0L*273K}{298K*0.99atm}\\\\V_2=1.80L[/tex]

Which means that the underwent a compression.

Best regards!

Taking into account the combined gas law, the volume of the dry hydrogen gas at 273 K and a pressure of 1 atm is 1.78 L.

Gay-Lussac's law states that when there is a constant volume, as the temperature increases, the pressure of the gas increases. And when the temperature is decreased, the pressure of the gas decreases.

Mathematically, this law indicates that the quotient between pressure and temperature is constant:

[tex]\frac{P}{T}=k[/tex]

Boyle's law says that the volume occupied by a certain gaseous mass at constant temperature is inversely proportional to pressure.

Boyle's law is expressed mathematically as:

P× V = k

Charles's law states that for a given sum of gas at constant pressure, as the temperature increases, the volume of the gas increases and as the temperature decreases, the volume of the gas decreases. That is, temperature and volume are directly proportional.

In summary, Charles's law is a law that says that when the amount of gas and pressure are kept constant, the ratio that exists between the volume and the temperature will always have the same value:

[tex]\frac{V}{T}=k[/tex]

Combined law equation is the combination of three gas laws called Boyle's, Charlie's and Gay-Lusac's law:

[tex]\frac{PxV}{T}=k[/tex]

Studying two different states, an initial state 1 and a final state 2, it is satisfied:

[tex]\frac{P1xV1}{T1}=\frac{P2xV2}{T2}[/tex]

In this case you know:

Replacing in the combined gas law:

[tex]\frac{0.97 atmx2 L}{298 K}=\frac{1 atmxV2}{273 K}[/tex]

Solving:

[tex]\frac{0.97 atmx2 L}{298 K}\frac{273 K}{1 atm} =V2[/tex]

1.78 L= V2

In summary, the volume of the dry hydrogen gas at 273 K and a pressure of 1 atm is 1.78 L.

Learn more about the combined gas law:

Gold have a greater mass

Density is a quantity derived from the mass and volume  

Density is the ratio of mass per unit volume  

The unit of density can be expressed in g/cm³ or kg/m³  

Density formula:  

[tex]\large {\boxed {\bold {\rho ~ = ~ \frac {m} {V}}}}[/tex]

ρ = density  

m = mass  

v = volume  

[tex]\tt mass=\rho\times V\\\\mass=10.5\times 5=52.5~g[/tex]

[tex]\tt mass=\rho\times V\\\\mass=19.3\times 5=96.5~g[/tex]

Answer: Units. The SI derived unit of frequency is the hertz (Hz), named after the German physicist Heinrich Hertz. One hertz means that an event repeats once per second.

The frequency is the number of waves that pass a point in space during any time interval, usually one second. We measure it in units of cycles (waves) per second, or hertz. The frequency of visible light is referred to as color, and ranges from 430 trillion hertz, seen as red, to 750 trillion hertz, seen as violet.

Frequency of an electromagnetic wave is the number of wave cycles per unit time. The SI unit of frequency is Hertz or Hz. Frequency is represented by the symbol v called neu.

Waves are propagation or transfer of energy through air or vacuum. An electromagnetic wave is associated with a combined electric field and magnetic field.

Waves are associated with characteristic frequency and wavelength. Wavelength of a wave is the distance between its two consecutive crests or troughs.

Frequency of a wave is the number of wave cycles per unit time. Its is expressed in the unit of Hertz or Hz. Frequency and wavelength are in inverse relation. The shortest waves have greater energy and greater frequency.

Frequency is inverse of time of propagation. So that it can also be used in s⁻¹ which is equal to one hertz.

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Answer:

2-pentene or pent-2-ene

Answer:

The molar mass and molecular weight of Al(CH3CO2)3 is 204.1136.

Explanation:

Answer:

168.1 g/mol

General Formulas and Concepts:

Chemistry

Explanation:

Step 1: Define

Al(CH₃O₂)₃

Step 2: Find molar masses

Molar Mass of Al - 26.98 g/mol

Molar Mass of C - 12.01 g/mol

Molar Mass of H - 1.01 g/mol

Molar Mass of O - 16.00 g/mol

Molar Mass of Al(CH₃O₂)₃ - 26.98 + 3(12.01) + 9(1.01) + 6(16.00) = 168.1 g/mol