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3 years ago

A student needs 500 mL of a 1.5 M solution of NaCl for an experiment. How many moles of NaCl should she use?

Chemistry

1 answer:

masha68 [24]3 years ago

5 0

Answer:

She should use 0.75 mol.

Explanation:

By definition, molarity (M) is the number of moles of solute per liter of solution. One liter of solution is equal to 1000 mL.

Therefore,

1000 mL -------- 1.5 moles of NaCl

500 mL --------- x= 0.75 moles of NaCl

The moles contained in 500 mL of a 1.5 M NaCl solution are 0.75.

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Water's ________ specific heat makes it heat up and cool down slowly; this stability has helped water support life.

Valentin [98]

Answer:

high

Explanation:

8 0

3 years ago

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Given the following data:N2(g) + O2(g)→ 2NO(g), ΔH=+180.7kJ2NO(g) + O2(g)→ 2NO2(g), ΔH=−113.1kJ2N2O(g) → 2N2(g) + O2(g), ΔH=−163

statuscvo [17]

Answer:

ΔH = +155.6 kJ

Explanation:

The Hess' Law states that the enthalpy of the overall reaction is the sum of the enthalpy of the step reactions. To do the addition of the reaction, we first must reorganize them, to disappear with the intermediaries (substances that are not presented in the overall reaction).

If the reaction is inverted, the signal of the enthalpy changes, and if its multiplied by a constant, the enthalpy must be multiplied by the same constant. Thus:

N₂(g) + O₂(g) → 2NO(g) ΔH = +180.7 kJ

2NO(g) + O₂(g) → 2NO₂(g) ΔH = -113.1 kJ

2N₂O(g) → 2N₂(g) + O₂(g) ΔH = -163.2 kJ

The intermediares are N₂ and O₂, thus, reorganizing the reactions:

N₂(g) + O₂(g) → 2NO(g) ΔH = +180.7 kJ

NO₂(g) → NO(g) + (1/2)O₂(g) ΔH = +56.55 kJ (inverted and multiplied by 1/2)

N₂O(g) → N₂(g) + (1/2)O₂(g) ΔH = -81.6 kJ (multiplied by 1/2)

------------------------------------------------------------------------------------

N₂O(g) + NO₂(g) → 3NO(g)

ΔH = +180.7 + 56.55 - 81.6

ΔH = +155.6 kJ

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3 years ago

At 333 k, which of the pairs of gases below would have the most nearly identical rates of effusion?

rjkz [21]

E. co and n2Effusion is the process where gas escapes through a hole. Gases with a lower molecular mass effuse more speedy than gases with a higher molecular mass. Relative rates of effusion is related to the molecular mass.
a) M(N₂)/M(O₂) = 28/32 = 0,875
b) M(N₂O)/M(NO₂) = 44/46 = 0,956
c) M(CO)/M(CO₂) = 28/44 = 0,636
d) M(NO₂)/M(N₂O₂) = 44/58= 0,758
e) M(CO)/M(N₂) = 28/28 = 1, CO and N₂ have iexact molecular masses and will effuse at nearly identical rates.

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3 years ago

Mario uses a hot plate to heat a beaker of 50mL of water. He used a thermometer to measure the temperature of the water. The wat

Alex777 [14]

Answer:

The boiling point decreases as the volume decreases.

Explanation:

The Temperature - Volume law otherwise called as Charles law is applied, which says that the volume of the given gas at constant pressure is directly proportional to the temperature measured in Kelvin. As the volume increases, the temperature also increases, if the volume decreases, then the temperature also decreases.

As per the Charles law, here the volume is decreased from 50 ml to 25 ml so the boiling point also decreases.

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3 years ago

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¿Cuál de los siguientes no es un ejemplo de movimiento de masas?

babunello [35]

Which of the following is not an example of a mass movement?

to. a. Ground slides b) acid rain c. mud flow d. drop

Answer:

b) acid rain

Explanation:

Acid rain is not an example or a type of mass movement.

Mass movement or mass wasting is the movement of rocks, soils and other debris downslope under the influence of gravity.

Water, slope and gravity are triggers of mass movement.

Acid rain is a not a form of mass movement
It occurs with some certain gases mixes rain water to produce an acidic precipitation.
When the water falls to the each surface, it causes problems to the ecosystem and can also corrode building materials.

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3 years ago