Help with chemistry question please

Answer:

The idea here is that you can use the heat absorbed by the solution to find the heat given off by the dissolution of the salt.

More specifically, you can assume that

Δ

H

diss

=

−

q

solution

The minus sign is used here because heat lost carries a negative sign.

To find the heat absorbed by the solution, you can use the equation

q

=

m

⋅

c

⋅

Δ

T

−−−−−−−−−−−−−

Here

q

is the heat gained by the water

m

is the mass of the water

c

is the specific heat of water

Δ

T

is the change in temperature, defined as the difference between the final temperature and the initial temperature of the sample

As the problem suggests, you can approximate the mass and the specific heat of the solution to be equal to those of the pure water sample.

The temperature increases by

0.121

∘

C

, so you know that

Δ

T

=

0.121

∘

C

→

positive because the final temperature is higher than the initial temperature

Plug in your values to find

q

=

125

g

⋅

4.18 J

g

−

1

∘

C

−

1

⋅

0.121

∘

C

q

=

63.22 J

So, you know that the solution absorbed

63.22 J

, which implies that the dissolution of the salt gave off

63.22 J

. In other words, you have

Δ

H

diss

=

−

63.22 J

Convert the mass of sodium hydroxide to moles by using the compound's molar mass

2.4

⋅

10

−

4

g

⋅

1 mole NaOH

39.997

g

=

6.00

⋅

10

−

6

moles NaOH

You know that the enthalpy of dissolution when

6.00

⋅

10

−

6

moles of sodium hydroxide are dissolved in water, so use this info to find the enthalpy of dissolution when

1

mole of the salt dissolves

1

mole NaOH

⋅

−

63.22 J

6.00

⋅

10

−

6

moles NaOH

=

−

1.054

⋅

10

7

J

Finally, convert this to kilojoules

1.054

⋅

10

7

J

⋅

1 kJ

10

3

J

=

1.054

⋅

10

4

kJ

Therefore, you can say that the enthalpy of dissolution, or molar enthalpy of dissolution, for sodium hydroxide is

Δ

H

diss

=

−

1.1

⋅

10

4

.

kJ mol

−

1

−−−−−−−−−−−−−−−−−−−−−−−−−−−

The answer is rounded to two sig figs, the number fo sig figs you have for the mass of sodium hydroxide.

SIDE NOTE The accepted value for the enthalpy of dissolution of sodium hydroxide in water at

25

∘

C

is

Δ

H

diss

=

−

44.51 kJ

Explanation:

i hope its right

Answer: Trail 2

Explanation: Because it has a pressure of 1 atm

Answer:

temperature is the answer

Answer:

Magnesia, or magnesium oxide, is a mineral composed of alkaline earth metals. The majority of today's magnesium oxide comes from calcining natural minerals.

Explanation:

I hope this helps you

:)

Answer:

Transfer of electrons between atoms

Explanation:

Just because it has the prefix "oxi" it doesn't necessarily mean that oxygen exists as a reactant.

Making and breaking ionic compounds happen right before or after redox reactions after the atoms or ions are modified into one another.

precipitation occurs during the redox rxns involved in electrolysis & daniel cells. but it is not a key factor.

Answer:

Explanation:

density = 19.32

Mass = 4.05 g

V = ?

Formula

Density = mass / volume or

volume = mass / density.

Solution

volume = mass / volume

volume = 4.05 / 19.32

Volume = 2.10

The solid cube has a side length of ∛V which reads as the cube root of volume.

Side Length = ∛2.10 = 0.594 cm

Answer:

All of the above

Explanation:

Their all chemical change

Answer: c

Explanation: just took the test and got it right

27. I think that's the answer

The molar mass of CuCl2 is 134.452 g/mol. Each element's molar mass can be found in its designated box on the periodic table.

Answer:

in constant and random motion

Explanation:

As the gas molecules collide with the walls of a container, the molecules impart momentum to the walls, producing a force that can be measured. ... The molecules are in constant random motion, and there is an energy (mass x square of the velocity) associated with that motion.

1.461 grams of NaCl must be dissolved in 1 liter solution to make 25 mM of NaCl solution according to molar concentration.

Molar concentration is defined as a measure by which concentration of chemical substances present in a solution are determined. It is defined in particular reference to solute concentration in a solution . Most commonly used unit for molar concentration is moles/liter.

The molar concentration depends on change in volume of the solution which is mainly due to thermal expansion. Molar concentration is calculated by the formula, molar concentration=mass/ molar mass ×1/volume of solution in liters.

In terms of moles, it's formula is given as molar concentration= number of moles /volume of solution in liters.

Millimolar concentration is also calculated by the same formula just the difference in units is present. According to the data given and substitution in the formula,

mass= 25×58.44×1=1461 mg or 1.461 g

Thus, 1.461 g of sodium chloride is required to make 25 mM  solution.

Learn more about molar concentration,here:

https://brainly.com/question/21841645

#SPJ2

Answer:

Brainliest pls

Explanation:

Dichotomous keys are exceptionally valuable since they permit non-master clients to distinguish living beings by guiding them to check the known, significant creatures out

This problem is providing the volume, temperature and pressure of a gas and asks for the number of moles at such conditions, which turns out to be 0.0160 mol.

In chemistry, we study ideal gases, which are assumed to be perfectly spherical and with no relevant neither attractions nor repulsions among molecules, with the widely-known ideal gas equation relating volume, temperature, pressure and moles as follows:

[tex]PV=nRT[/tex]

Thus, knowing it is in a 0.300-L vessel at 15.0 °C and 157.6 kPa, one can solve for n in the previous equation to get:

[tex]n=\frac{PV}{RT}[/tex]

And plug in by making sure the pressure is in atmospheres and the temperature in kelvins:

[tex]n=\frac{157.6kPa*\frac{1atm}{101.325kPa}*0.300L}{(0.08206\frac{atm*L}{mol*K})*(15.0+273.15)K}\\\\n=0.0160mol[/tex]

Learn more about ideal gases: brainly.com/question/8711877

[tex]\\ \tt\Rrightarrow pH=-log[H^+][/tex]

[tex]\\ \tt\Rrightarrow 1.82=-log[H^+][/tex]

[tex]\\ \tt\Rrightarrow log[H^+]=-1.82[/tex]

[tex]\\ \tt\Rrightarrow [H^+]=10^{-1.82}[/tex]

[tex]\\ \tt\Rrightarrow [H^+]=0.015M[/tex]

Nonrenewable natural resources are resources that cannot be replenished within a lifetime.

The pressure of NO2 and N2O4 would be 1.756 atm and 0.1542 atm respectively.

According to Boyle's law, the pressure of a gas is inversely proportional to its volume at a constant temperature.

Mathematically: P1V1=P2V2

When the volume of a gas is halved at a constant temperature, the pressure is doubled. If it is the volume is doubled, the pressure would be halved.

In this case, the volume of the container is halved. Meaning that the pressure of each of the gas would be doubled by the time the equilibrium is reestablished.

Thus, NO2 would double from 0.878 atm to 1.756 atm while N2O4 will double from 0.0771 atm to 0.1542 atm

More on gas laws can be found here: https://brainly.com/question/1190311

Answer:

the second one

Explanation:

because all of them are under

The empirical formula of this compound is equal to [tex]Fe_{2}O_3[/tex].

To calculate the empirical formula of a compound, it is necessary to know the number of moles present.

Therefore, we will use the molar mass of iron and oxygen to find the amount of moles, so that:

[tex]MM_O = 16g/mol\\MM_Fe = 55.8g/mol[/tex]

                                        [tex]MM = \frac{m}{mol}[/tex]

                                            [tex]16 = \frac{4.8}{mol}[/tex]

                                            [tex]mol = 0.3[/tex]

                                               [tex]55.8 = \frac{11.2}{mol}[/tex]

                                               [tex]mol = 0.2[/tex]

Finally, as the empirical formula is composed of integers numbers of moles, just multiply the values ​​by the smallest common factor to transform into an integer, so that:

                                       O =>  [tex]0.3 \times 10 = 3moles[/tex]

                                       Fe => [tex]0.2 \times 10 = 2moles[/tex]

So, the empirical formula of this compound is equal to [tex]Fe_{2}O_3[/tex]

Learn more about empirical formula in: brainly.com/question/1363167

The mass of hydrazine (N₂H₄) required to produce 96 g of water (H₂O) is 85.4 g (Option C)

N₂H₄ + O₂ —> N₂ + 2H₂O

Molar mass of N₂H₄ = (2×14) + (4×1) = 32 g/mol

Mass of N₂H₄ from the balanced equation = 1 × 32 = 32 g

Molar mass of H₂O = (2×1) + 16 = 18 g/mol

Mass of H₂O from the balanced equation = 2 × 18 = 36 g

SUMMARY

From the balanced equation above,

36 g of H₂O were produced by 32 g of N₂H₄

From the balanced equation above,

36 g of H₂O were produced by 32 g of N₂H₄

Therefore,

96 g of H₂O will be produced by = (96 × 32) / 36 = 85.4 g of N₂H₄

Thus, 85.4 g of N₂H₄ is needed for the reaction

Learn more about stoichiometry:

https://brainly.com/question/14735801

By using the given ratio, we will find that, out of 500kg of water, we could produce 55kg of hydrogen gas.

We know that out of 100 grams of water, we can produce 11 grams of hydrogen gas.

Taking the quotient we get the ratio:

(11g/100g) = 0.11

We could conclude that for any mass of water we can produce 0.11 times that mass of hydrogen gas.

This means that if we have 500kg of water, then we can produce:

0.11*500kg = 55kg of hydrogen gas.

If you want to learn more about ratios, you can read:

https://brainly.com/question/1781657

Answer:

d

Explanation:

H3O =1×10_12=12 ooh is 12

Answer:

When the light energy from sunlight hits matter, heat energy is formed

Answer:

A

Explanation:

when light energy hit matter heat energy formed

1.81 E 24 formula units are in 366 grams of XPO4.

The formula units of a compound can be calculated using the following expression:

First, we calculate the molar mass of XPO4 as follows:

XPO4 = 26.98 + 31 + 16(4) = 121.98g/mol

moles = 366g ÷ 121.98g/mol

moles = 3mol

Next, we multiply the number of moles by 6.02 × 10²³

formula units = 6.02 × 10²³ × 3 = 1.81 × 10²⁴

Therefore, 1.81 E 24 formula units are in 366 grams of XPO4.

Learn more about formula units at: https://brainly.com/question/19293051

We can confirm that when placed into water, the compound will break up into ions almost completely.

This has to do with the fact that strong electrolytes tend to become completely ionized when placed in water. This means that the compound dissolves completely and breaks up into ions if enough water is present.

Therefore, we can confirm that the compound will break up into ions almost completely when placed into water.

To learn more about ions visit:

https://brainly.com/question/1782326?referrer=searchResults

The activation energy (Ea)  for the reaction is calculated from the slope as is - 1.16kJ.

The Arrhenius equation relates the rate constant of a reaction to the temperature of the reaction. It is an offshoot of the collision theory. We must note that the collision factor A is the y intercept of the graph.

Given that T = -350 K

R = 8.314 J/K.mol

Ea = ??

-350 = Ea/8.314

Ea = -350 × 8.314

Ea = - 1.16kJ

Learn more about activation energy:https://brainly.com/question/11334504

Answer:

52.0 gof CO2 contains 7.1 *10^23 molecules

1 molecule of CO2 has a mass of 7.3*10^-23 grams

Explanation:

Step 1: Data given

Mass of CO2 = 52.0 grams

Molar mass of CO2 = 44.01 g/mol

Number of Avogadro = 6.022 * 10^23 / mol

Step 2: Calculate moles of CO2

Moles CO2 = Mass CO2 / molar mass CO2

Moles CO2 = 52.0 grams / 44.01 g/mol

Moles CO2 = 1.18 moles

Step 3: Calculate molecules in 1.18 moles CO2

Number of molecules = 1.18 moles * 6.022*10^23 = 7.1 *10^23 molecules

1 molecule of CO2

Number of moles = 1 / 6.022*10^23

Number of moles = 1.66 *10^-24

Mass CO2 = 1.66*10^-24 moles * 44.01 g/mol

Mass CO2 = 7.3*10^-23 grams

Answer:

0.12 dm³ or 120 cm³

Explanation:

Hi there!

so first step find the number of moles

number of moles = mass ÷ Ar ( since o is an element and when it is alone, it is a diatomic molecule {O2} )

number of moles = mass ÷ Ar

number of moles = 0.16 ÷ ( 16 × 2 )

= 0.16 ÷ 32

= 5 × 10 ( power -3)

1 mol of O2 = 24 dm³ or 24 000 cm³

5 × 10 ( power -3) of O2 = (5 × 10 ( power -3)) × 24

= 0.12 dm³

or

= (5 × 10 ( power -3)) × 24 000

= 120 cm³