Based on the enthalpy changes given for the reactions, which reactions are endothermic?

Answer:

Tussar silk

Charmeuse

Explanation:

Hope this helps! :)

Answer:

2.34 %

Explanation:

Since the density of the Jello, ρ = 1.14 g/mL and ρ = m/v where m = mass of jello and v = volume of jello = 475 mL.

So, m = ρv

substituting the values of the variables into the equation, we have

m = ρv

m = 1.14 g/mL × 475 mL = 541.5 g

Since we have 13 g of sugar in the jello, the total mass present is 13 g + 541.5 g = 554.5 g

So, the percentage by mass of sugar present % m/m = mass of sugar present/total mass × 100 %

= 13 g/554.5 g × 100 %

= 0.0234 × 100 %

= 2.34 %

So, the percentage by mass of sugar present % m/m = 2.34 %

put the glass lid on and turn or turn down the heat

Answer:

The energy absorbed in the first move is greater than the energy released in the second move

Explanation:

Electrons require (absorb) energy to move to a higher energy level when there is a large external heat source, the presence of an electric field or by colliding with other electrons

And the amount of energy absorbed by the electron is exactly equal to the change in the energy state between the initial energy level of the electron and the destination energy level

Therefore, given that the energy level of the electron at level 2 is higher than the energy level of the electron when at level 1, we have;

The difference in the energy level between level 4 and level 1 is greater than the difference in the energy level between level 4 and level 2 and more energy is absorbed and therefore, released when the electron moves from level 1 to level 4 than when the electron drops from level 4 to level 2.

The most likely result is that 'the energy absorbed in the first move is greater than the energy released in the second move'.

Answer:

4000mL

Explanation:

Using the combined gas law equation as follows:

P1V1/T1 = P2V2/T2

Where;

P1 = initial pressure (atm)

P2 = final pressure (atm)

V1 = initial volume (mL)

V2 = final volume (mL)

T1 = initial temperature (K)

T2 = final temperature (K)

According to the information given in this question:

V1 = 1000mL

T1 = 20K

P1 = 1.0atm

V2 = ?

P2 = 0.5atm

T2 = 40K

Using P1V1/T1 = P2V2/T2

1 × 1000/20 = 0.5 × V2/40

1000/20 = 0.5V2/40

50 = 0.5V2/40

50 × 40 = 0.5V2

2000 = 0.5V2

V2 = 2000/0.5

V2 = 4000mL

Answer:

A. Fusion

Explanation:

Answer:

4.65 g x 1 mol/4.0026 g/mol = 1.162 mol helium

Explanation:

Answer:

Explanation:

a ) If N₂(g) and 3H₂(g) is added to the system , 2 moles of additional  ammonia will be produced .

b ) If pressure is decreased , less amount of ammonia will be formed, because forward reaction reduces the pressure. So, reaction will take place in reverse direction.

c ) Keq = [ NH₃ ] ² / [ N₂ ] [ H₂]³

d ) Substituting the given values in the equation ,

Keq = [ 6M ] ² / [ 3M] [ 4M]³

= 36 / 3 x 64 M⁻²

= 18.75 x 10⁻² M⁻² .

Answer: A

Explanation:

the melting point or boiling point of a substance at a specific pressure

Answer:

2 XE + 1 AB. --> 1 AE2 + 2 XB

Above equation is now balanced

Answer:

Explanation:

Nuclear reactors are the heart of a nuclear power plant. They contain and control nuclear chain reactions that produce heat through a physical process called fission. That heat is used to make steam that spins a turbine to create electricity. Nuclear power plants use heat produced during nuclear fission to heat water. The heat produced during nuclear fission in the reactor core is used to boil water into steam, which turns the blades of a steam turbine. As the turbine blades turn, they drive generators that make electricity

Answer:

As the kinetic energy of the gaseous solute increases, its molecules have a greater tendency to escape the attraction of the solvent molecules and return to the gas phase. Therefore, the solubility of a gas decreases as the temperature increases.

Explanation:

As the kinetic energy of the gaseous solute increases, its molecules have a greater tendency to escape the attraction of the solvent molecules and return to the gas phase. Therefore, the solubility of a gas decreases as the temperature increases

Answer:

your simpal answer is 177.32

Answer:

C

Explanation:

Angiosperms have developed these adaptations because it attracts pollinators which helps the ecosystem grow.

Taking into account the molar mass of each elemente and ammonia, the correct answer is the first option: the percentage composition of each element in ammonia, NH₃ is 82.35% N; 17.65% H

First of all, molar mass is the mass of one mole of a substance, which can be an element or a compound. In the case of a compound, it is calculated by adding the atomic masses of the atoms that make up the molecule.

In this case, being the atomic mass of N equal to 14 and the atomic mass of H equal to 1, the molar mass of NH₃ is calculated as:

NH₃= 14 + 3* 1= 17

Now, to obtain the percentage composition of each element, you must divide each individual atom with the mass of ammonia and multiply by 100 to obtain the percentage:

N: [tex]\frac{14}{17} x100[/tex]

H: [tex]\frac{1x3}{17} x100[/tex] In this case, the atomic mass of hydrogen H is multiplied by 3 because 3 hydrogens are present in ammonia.

Solving:

N: [tex]\frac{14}{17} x100[/tex]= 0.8235×100= 82.35 %

H: [tex]\frac{3}{17} x100[/tex]= 0.1765×100= 17.65 %

Finally, the correct answer is the first option: the percentage composition of each element in ammonia, NH₃ is 82.35% N; 17.65% H

Learn more:

https://brainly.com/question/11257506?referrer=searchResults

Answer: The mass of lead (II) nitrate required is 74.52 g

Explanation:

The number of moles is defined as the ratio of the mass of a substance to its molar mass.

The equation used is:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)

Given mass of lead (II) chloride = 62.6 g

Molar mass of lead (II) chloride = 278.1 g/mol

Plugging values in equation 1:

[tex]\text{Moles of lead (II) chloride}=\frac{62.6g}{278.1g/mol}=0.225 mol[/tex]

The chemical equation for the reaction of lead (II) chloride and sodium nitrate follows:

[tex]Pb(NO_3)_2+2NaCl\rightarrow PbCl_2+2NaNO_3[/tex]

By the stoichiometry of the reaction:

1 mole of lead (II) chloride is produced from 1 mole of lead (II) nitrate

Then, 0.225 moles of lead (II) chloride will react with = [tex]\frac{1}{1}\times 0.225=0.225mol[/tex] of lead(II) nitrate

Molar mass of lead (II) nitrate = 331.2 g/mol

Plugging values in equation 1:

[tex]\text{Mass of lead (II) nitrate}=(0.225mol\times 331.2g/mol)=74.52g[/tex]

Hence, the mass of lead (II) nitrate required is 74.52 g

Answer:

A. 5895 J/g*C)

Explanation:

An unknown substance weighing 42.0 g was heated from 36.0°C to 65.0°C. In this process, the substance absorbed 5895 J of energy.

Answer:

your awnser would be 72.1

Explanation:

hope this helps have a good day :]

Answer:

3132 is the answer

Explanation:

3BaCl2 + Al2S3 → 3BaS + 2AlCl3

Answer:

Explanation:

Hope this helps u !!

Answer:

Contrasting Nuclear Fission and Nuclear Fusion

Nuclear FissionByproducts of the reaction: Fission produces many highly radioactive particles.Conditions: Critical mass of the substance and high-speed neutrons are required.Energy Requirement: Takes little energy to split two atoms in a fission Explanation:

Answer:

sry, dk

Explanation:

Answer:

Gold and pyrite both have a brilliant metallic luster, but are different tones of yellow. Gold is golden to silvery yellow, whereas pyrite is a pale to medium brassy yellow that sometimes tarnishes.

Explanation:

Answer: The limiting reagent in the reaction is bromine.

Explanation:

Limiting reagent is defined as the reagent which is completely consumed in the reaction and limits the formation of the product.

Excess reagent is defined as the reagent which is left behind after the completion of the reaction.

Given values:

Moles of iron = 10.0 moles

Moles of bromine = 12.0 moles

The chemical equation for the reaction of iron and bromine follows:

[tex]2Fe+3Br_2\rightarrow 2FeBr_3[/tex]

By the stoichiometry of the reaction:

If 3 moles of bromine reacts with 2 moles of iron

So, 12.0 moles of bromine will react with = [tex]\frac{2}{3}\times 12.0=8moles[/tex] of iron

As the given amount of iron is more than the required amount. Thus, it is present in excess and is considered as an excess reagent.

Hence, bromine is considered a limiting reagent because it limits the formation of the product.

Thus, the limiting reagent in the reaction is bromine.

Answer:

External stimulus of thirst

Answer:

your answer is:         the external stimulus of thirst

Explanation:

I took the test :)) hope this helps!!!!!!

Answer:

The amount of energy required is 17 kJ.

Explanation:

Answer:

1.89 nol Cu(NO3)2

Explanation:

if you calculate it it will be 1.89

Answer:

d. pOH = 12 => pH = 14 - 10 = 2 => most acidic

Explanation:

pH = -log[H⁺] => [H⁺] = 10^-pH

By definition, if ...

[H⁺] > 10⁻⁷ > [OH⁻] => pH < -log(10⁻⁷) < 7 => pOH > 14 - 7 > 7 => acidic solution

[H⁺] = 10⁻⁷ = [OH⁻]  => pH = -log(10⁻⁷) = 7 => pOH = 14 - 7 = 7 => neutral solution

[H⁺] < 10⁻⁷ < [OH⁻]  => pH > -log(10⁻⁷) > 7 => pOH < 14 - 7 < 7 => basic solution

∴ From most basic to most acidic ...

a. pH = 12 => most basic

b. pOH = 5 => pH = 14 - 5 = 9

c. [H⁺] = 1 x 10⁻⁸ => pH = -log(10⁻⁸) = -(-8) = 8

d. pOH = 12 => pH = 14 - 10 = 2 => most acidic