Given the thermochemical equations
X₂ + 3 Y₂ → 2XY3 ΔH1= -340kJ
X₂ + 2Z₂ → 2XZ₂ ΔH2= -170 kJ
2Y2 + Z2 → 2Y₂Z ΔH3= -260 kJ

Calculate the change in enthalpy for the reaction.

4XY3 +7Z₂ → 6Y₂Z + 4 XZ₂

ΔH= ____ kJ

Energy, in kJ, is required to completely melt 20.0 g of ice initially at -45.0 °C is 4.147kJ

Energy is the capacity for doing work

Here given data is

Mass = 20.0 g

Temprature = -45.0°C

Molar heat of fusion of ice = 6.02 kj/mol

We have to calculate energy in kJ = ?

Then q = n×ΔH

q = heat

n = number of moles

ΔH = enthalpy

First we calculate the m=number of moles

Number  of moles = mass / molar mass

Number  of moles =  12.4 g/ 18 g/mol

Number  of moles =  0.69 mol

Now put this value in formula

q = n × ΔH

q =  0.69 mol×6.02 kj/mol

q = 4.147kJ

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The RMS speed of Cl₂ and He molecules at 411 K is 379.97m/s and 1600 m/s

In a gas, the root-mean-square speed is used to calculate particle speed, which is defined as the square root of the common velocity squared of the molecules in the gas. It is represented mathematically as vrms=3RT/M.

The average kinetic energy of gas molecules is proportional to temperature and inversely proportional to molecular weight.

The root mean square(RMS) speed of the molecule in a gas can be calculated using the following formula

Rms speed = √(3RT/M)

Here R is the gas constant, T is the absolute temperature and M is the molar mass of the gas molecule in kg/mol

Now we have to calculate the RMS speed of Cl₂ molecules at 411 K? and the RMS speed of He atoms at 411 K.

At 411 K, the RMS speed of Cl2 molecules is

RMS speed = √(3RT/M)

=√((3 x 8.314 x 411)/(71 x 10-3 ))

=√(10251.162/0.071)

= √144382.563

= 379.97m/s

RMS speed of He molecules at 411 K

RMS speed = √(3RT/M)

=√((3 x 8.314 x 411)/(4 x 10-3 ))

=√(10251.162/0.004)

= √2562790.5

= 1600 m/s

Therefore the RMS speed of Cl₂ and He molecules at 411 K is 379.97m/s and 1600 m/s

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Answer:

depends on the type of insulin, but your normal low everyday kind strach is stronger then insulin is stronger than cellulose

The isotopes of bromine from the options would be Z = 35,  A = 79.

Isotopes are atoms of the same element with the same atomic number but different neutron numbers.

The atomic number of an atom is the number of protons present in the nucleus of the atom. Since elements are arranged according to their atomic number on the periodic table, isotopes of the same element will occupy the same position on the periodic table.

Now, considering the isotope of bromine (Br). The atomic number is 35. The atomic number is denoted as Z on the periodic table. The normal bromine atom has a mass number of 80. With 35 as the number of protons, the number of neutrons can be calculated as:

80 - 35 = 45.

Considering an atom with Z = 35, A = 79, means the atomic number is 35, which means it is a bromine atom. The mass number is 79 instead of 80.

79 - 35 = 44.

This means that the atom has 44 as the neutron number instead of 45. Thus, Z = 35, A = 79 is the only isotope of bromine.

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¿What is a sulphurous gas?

Sulfur dioxide (SO) is a colorless gas with a pungent odor particular. Also called sulfite, it was used from centuries ago and its purpose is to preserve the aromas of the wine and the elimination of bacteria. It is also used in preservatives and antioxidants, and the food industries

They use it in dried fruit juices, jams and juices.

When a Kr-89 captures an electron, the particle that is formed is bromine with atomic number of 35.

Radioactivity is the spontaneous emission of ionizing radiation as a consequence of a nuclear reaction, or directly from the breakdown of an unstable nucleus.

The radiation emitted includes the following;

An electron is a negatively charged subatomic particle that can be either bound to an atom or free (not bound). It has a charge of -1.

According to this question, when a Kr-89 captures an electron, the particle formed can be deduced as follows:

89/36Kr + 0/-1e = 89/35Br

This suggests that the particle formed when a particle of krypton captures an electron is bromine.

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Answer:

0.714 m (app.)

Explanation:

use ∧ = c/f

here, ∧ = wavelength

c = velocity of light = 3 × 10^8 m/s

f = frequency = 4.2 × 10^8 Hz

Here's some examples

CH, OH, FH, etc

To research some substances pH 0 to less than 7 is acidic, 7 is neutral and more than 7 is neutral.

baking soda - base

Vinegar - acid

Distilled water - neutral

Pure rain - neutral

Ammonia -  nasic

Lemon juice -  acid

Hair and skin - acidic

An acid is a molecule or ion capable of both donating a proton, referred to as a Brønsted–Lowry acid, or forming a covalent bond with an electron pair, known as a Lewis acid. the first class of acids are the proton donors, or Brønsted–Lowry acids.

An acid is any substance that in water answer tastes sour, adjusts blue litmus paper to red, reacts with a few metals to liberate hydrogen, reacts with bases to form salts, and promotes chemical reactions (acid catalysis). An acid is a substance that produces hydrogen (H+) ions when it's far delivered to water. A hydrogen ion is simply the proton and no electron

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Explanation:

A mixture of a solid and a liquid

The small clay particles become suspended in the water. This kind of mixture is called a suspension. Suspensions are opaque; that means they are cloudy and we cannot see through them very well. The sugar dissolves in the water and the mixture is called a solution. Solutions are clear; that means we can see through them.

A mixture of a liquid and a liquid

Milk is not a single substance, but actually a mixture of two liquids! The one liquid component in milk is water, and the other is fatty oil. The reason milk is opaque is that tiny droplets of the oil is suspended in the water. When some liquids are suspended in liquid, we call the mixture an emulsion. Like suspensions, emulsions tend to be opaque.A mixture of vinegar and water is clear, and that is a clue that the mixture is a solution.

Solutions are special kinds of mixtures in which the particles are so well mixed that they are not separated from each other. We cannot make out separate substances.

A mixture of a gas and a gas

We learnt in that Materials that the particles of gases are far apart. This means that gases can mix very easily, because it is easy for their particles to move in amongst each other. The air we breathe is not a single gas but actually a mixture of gases

The volume of the 0.240M sulfuric acid required to completely react with sodium hydroxide will be

Firstly we will write the correct balanced equation for the reaction:

2NaOH + H₂SO₄ ==> Na₂SO₄ + 2H₂O

Next, determine moles of NaOH present:

75.5 g NaOH x 1 mole NaOH/151 g = 0.5 moles NaOH

Next, determine number of moles H₂SO₄ needed to react with 0.5 moles NaOH,

0.5 moles NaOH x 1 mole H₂SO₄ /2 moles NaOH = 0.25 moles H₂SO₄ needed

Finally, calculate the volume of H₂SO₄ needed to provide 0.25 moles H₂SO₄:

(0.240 mole/L)(x L) = 0.25 moles

Molarity= 0.25/ volume

volume = 0.25/ molarity

= 0.25/ 0.24

=1.04 L

= 1040 mL

So, the volume of the given solute required to completely react with sodium hydroxide will be 1040 mL.

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The container volume and the temperature do not change, the pressure of the gas mixture after the complete decomposition of N₂O is 3 atm.

The reaction is given as :

2N₂O ---->  2N₂   +   O₂

volume = 2.95 L

temperature = 734 + 273 = 1007 K

mass = 5.10 g

moles = mass / molar mass

          = 5.10 / 44

          =  0.11 mol

using ideal gas equation here:

P V = n RT

P = (0.11 × 0.082 × 1007) / 2.95

P   = 3 atm

Thus, The container volume and the temperature do not change, the pressure of the gas mixture after the complete decomposition of N₂O is 3 atm.

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If there are any actual values of x for which f(x) = zero then the curve isn't always absolutely above or beneath the axis.

Check the values of y. All values positive -> curve is above y-axis. All values negative -> curve is beneath y-axis. There also are different cases. The curve might (for example) intersect the x-axis.

Adding to the output of a feature actions the graph up. Subtracting from the output of a feature actions the graph down. Here are the graphs of y = f (x), y = f (x) + 2, and y = f (x) - 2.

If the slope of f(x) is negative, then the graph of f'(x) might be beneath the x-axis. If the slope of f(x) is positive, then the graph of f'(x) might be above the x-axis. All relative extrema of f(x) turns into x-intercepts of f'(x).

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Answer:

Boron trifluoride |

Explanation:

Boron trifluoride is a colorless gas

The atomic number(Z) is equal to the number of protons to equal to number of electrons.

The number of neutrons is equal to atomic mass minus the atomic number

n=A-Z

For Zn^2+, Z=28, e=28

For iron, Z=25,A=55

The number of neutrons is 55-25=30

The charge is zero

For O^2-, Z=8+2=10, n=p=10

The number of neutrons is 16-10=6

For sulfur, Z=16,A=34

For S2-, Z=16+2=18, A=34

The charge is 2-

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Considering the ideal gas law, the correct answer is the second option: 0.0594 moles of a gas are in a 4.2L container at 310K at 0.36atm

An ideal gas is called a hypothetical or theoretical gas, which would be composed of particles that move randomly and without interacting with each other.

The pressure, P, the temperature, T, and the volume, V, of an ideal gas, are related by a simple formula called the ideal gas law:

P×V = n×R×T

where:

In this case, you know:

Replacing in the ideal gas law:

0.36 atm× 4.2 L = n× 0.082 (atm×L)/(mol×K)× 310 K

Solving:

(0.36 atm× 4.2 L)÷ (0.082 (atm×L)/(mol×K)× 310 K)= n

0.0594 moles= n

Finally, the number of moles of gas is 0.0594 moles.

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Answer:

Example problem

Explanation:

A 6.00 L sample at 25.0 °C and 2.00 atm contains 0.500 mol of gas. If we add 0.250 mol of gas at the same pressure and temperature, what is the final total volume of the gas?

Solution

The formula for Avogadro's law is:

V1/n1=V2/n2

V1=6.00 L

n1=0.500 mol

V2=?

;m

ml

n2=0.500 mol + 0.250 mol = 0.750 mol

V2=V1×n2/n1

V2=6.00 L×0.750mol

0.500

mol=9.00 L

At constant temperature and volume, more I2 is added to the above equilibrium. A new state of equilibrium results from a shift to the:

Left with a net decrease in [H2].

Hence, Option A is correct .

What do you mean by equilibrium in chemistry?

Chemical equilibrium, can be defined as the reversible chemical reaction in which there is  no net change in the amounts of reactants and products. Types of chemical equilibrium are  Homogeneous Equilibrium and Heterogeneous Equilibrium

It plays a important role in chemical reaction

Rate of forward reaction =  Rate of backward reaction.

Hence , At constant temperature and volume, more I2 is added to the above equilibrium. A new state of equilibrium results from a shift to the:

Left with a net decrease in [H2].

Hence, Option A is correct .

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An acetone with a density of 0.7857 g/mL and a mass of 0.3201 lbs will have a volume of 184.796 mL.

What is density?

The density of a substance is a function of its mass and volume. The variables are related to each other, such that:

Density = mass/volume.

Thus, given any two of the 3 variables, the third variable can be calculated by making it the subject of the formula.

Now to the problem at hand. The acetone has a density of 0.7867 g/mL and a mass of 0.3201 lbs. Because the unit of density is g/mL, the mass in lbs first needs to be converted to grams.

1 lb = 453.592 grams

0.3291 lbs = 0.3201 x 453.592

                  = 145.194 grams

Now, let's make volume the subject:

volume = mass/density

             = 145.194/0.7857

             = 184.796 mL

In summary, acetone with a density of 0.7857 g/mL and a mass of 0.3201 lb will have a volume of 184.796 mL.

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We can change the freedom of movement in molecules of a substance by the addition or removal of heat.

Molecules are the smallest particles of a substance that are capable of independent existence and that still retain the properties of that substance.

The movement of the molecules of a substance is dependent on the strength of the force of attraction between the molecules of the substance.

The stronger the attractive forces between the molecules of a substance, the less free the molecules of the substance will be to move.

The molecules of a substance can acquire energy to overcome these attractive forces when heat is added to the substance.

Hence, an increase or decrease in the temperature of a substance will change the movement of the molecules of the substance.

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The change in internal energy for the system is 5.656 kJ/ mole.

Internal energy is defined as the quality or state function that describes a substance's energy in the absence of capillary effects and the impacts of external magnetic, electric, and other fields. Geothermal heat from the earth's core and high-temperature mantle is the main source of internal energy for the planet.

Given,

Δq = 7.070 kJ

P∆V = 1.414 kJ

As we know that

Δq = ΔU + P∆V

So, ΔU = Δq - P∆V

ΔU = 7.070 kJ - 1.414 kJ

ΔU  = 5.656 kJ / mole

Thus, the change in internal energy for the system is 5.656 kJ/ mole.

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If a single grain of rice weighs 0.000064 lb and assuming 1 grain of rice is counted per second, the number of days to count 10 lb of rice would be 1.8084 days.

According to the analysis:

1 grain = 0.000064 lb

This means that 0.000064 lb is counted per second according to the rate given.

There is a total of 10 lb of rice, how many 0.000064 lb can be deducted from 10 lb?

10/0.000064  = 156250

In other words, there are 156250 grains of rice in total.

1 grain = 1 sec

How many seconds will it take to count 156250 grains?

156250 x 1 = 156250 seconds

60 seconds = 1 minute

60 minutes = 1 hour

124 hours = 1 day

Total number of seconds in a day (24 hours) = 60 x 60 x 24

                                                                           = 86400 seconds

So, how many 86400 seconds can be deducted from 156250 seconds?

156250/86400 = 1.8084

Thus, it will take a total of 1.8084 days to count 10 lb of rice grains.

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The pH of acid is between 0-7 on pH scale while for base pH range is from 7-14. Therefore, the concentration of [H3O+] in the solution is [tex]10^{11.4}[/tex]. pH is a unitless quantity

pH is a measurement of amount of hydronium ion H₃O⁺ in a given sample. More the value of hydronium ion concentration, more will be the solution acidic.

On subtracting pH from 14, we get pOH which measures the concentration of hydroxide ion in a given solution. pH depend on the temperature. At room temperature pH scale is between 0 to 14. pH of neutral solution is 7.

Mathematically,

pH=-log[H⁺]=11.4

Solving this

[H⁺]=[tex]10^{11.4}[/tex]

Therefore, the concentration of [H3O+] in the solution is [tex]10^{11.4}[/tex].

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Answer:

(e) 148.2. However, it should be expressed only to 3 significant figures since 2.00 only has 3.

Answer:

A metal + polyatomic anion.

Explanation:

Taking into account the reaction stoichiometry,14.9856 L of O₂ are needed to react completely with 10.0 L of H₂S at STP?

In first place, the balanced reaction is:

2 H₂S + 3 O₂ → 2 SO₂ + 2 H₂O

By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:

The STP conditions refer to the standard temperature and pressure. Pressure values at 1 atmosphere and temperature at 0 ° C are used and are reference values for gases. And in these conditions 1 mole of any gas occupies an approximate volume of 22.4 liters.

First of all, you know that 10.0 L of H₂S react at STP. You can apply the following rule of three: if by definition of STP conditions 22.4 L of H₂S are occupied by 1 mole, 10 L of H₂S are occupied by how many moles?

moles of H₂S= (10 L× 1 mole)÷ 22.4 L

moles of  H₂S= 0.446 moles

To calculate the number of moles of O₂ required, the following rule of three can be applied: If by reaction stoichiometry 2 moles of H₂S react with 3 moles of O₂, 0.446 moles of H₂S react with how many moles of O₂?

moles of O₂= (0.446 moles of H₂S× 3 moles of O₂)÷2 moles of H₂S

moles of O₂= 0.669 moles

Now, you can apply the following rule of three: if by definition of STP conditions 1 mole of O₂ occupies a volume of 22.4 liters, 0.669 moles occupies how much volume?

volume= (0.669 moles× 22.4 L)÷ 1 L

volume= 14.9856 L

Finally, 14.9856 L of O₂ are needed.

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The mass of the steel bar is 26.7 g.

the specific heat capacity expression is given as :

Q = m c ΔT

Q steel = Q water

where,

specific heat for water = 0.452 J/ g ° C

specific heat capacity for steel = 4.18 J/ g ° C

Q steel = -Q water

m c ΔT =  - m c ΔT

85 × 0.452 × (19.2) = m × 4.18 ×0.8

mass of steel = 26.7 g

Thus, A volume of 85.0 mL of H2O is initially at room temperature (22.00 ∘C ). A chilled steel rod at 2.00 ∘C is placed in the water. If the final temperature of the system is 21.20 ∘C , the mass of the steel bar is 26.7 g.

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Answer:

Most likely A

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Answer: it erases the blue oxidized copper and returns it to its pristine original look

Explanation:

The more cooper there is the better the ammonia will work