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3 years ago

Where does the light that makes the moon visible come from?

2 answers:

6 0

The answer is D. the sun.

Explanation: At night, the moon blocks the sun, while absorbing the light of the sun as-well.

nirvana33 [79]3 years ago

3 0

D. The sun is the correct answer

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b) 2C2H2(g) + 5O2(g)⟶4CO2(g) + 2H2O(l) 6.54 Calculate the heats of combustion for the following reactions from the standard enth

IRINA_888 [86]

Answer:

a. ΔH⁸ = -1420 kJ/mol b. ΔH⁸ = -1144.84 kJ/mol

Explanation:

C₂H₄ (g) + 3 O₂ (g) ------------------------ 4 CO₂ (g) + 2 H₂O (l) ΔH⁸ = ?

ΔH⁸f kJmol 52.47 0 -399.5 -285.83

ΔH⁸ = 2(-399.5) + 2 (-285.83) - (52.47)

ΔH⁸ = -1420 kJ/mol

H₂S (g) + 3 O₂ (g) ---------------------- 2 H₂O (l) + 2 SO₂ (g)

ΔH⁸f kJmol -20.50 0 -285.83 -296.84

ΔH⁸ = 2(-285.83) + 2 (-296.84) - (-20.50)

ΔH⁸ = -1144.84 kJ/mol

4 0

3 years ago

If 27 ml of 6.0 m h2so4 was spilled, what is the minimum mass of nahco3 that must be added to the spill to neutralize the acid?

katrin [286]

The minimum mass of NaHCO3 that must be added to the spill to neutralize the acid is 27.216 grams

<h3>calculation </h3>

write the balanced chemical equation

2NaHCO3 +H2SO4 → Na2SO4 +2H2O +2CO2

find the moles of H2SO4 = molarity x volume in liters

volume in liters = 27/1000=0.027 l

moles is therefore= 0.027 x6=0.162 moles

by use of mole ratio of NaHCO3: H2SO4 which is 2:1 the moles of NaHCO3=0.162 x2=0.324 moles

mass of NaHCO3= moles of NaHCO3 x molar mass of NaHCO3(84g/mol)

= 84g/mol x 0.324=27.216 grams

8 0

4 years ago

Read 2 more answers

Nitrogen dioxide is used industrially to produce nitric acid, but it contributes to acid rain and photochemical smog. What volum

Strike441 [17]

Answer:

35.41 L

Explanation:

Given, Volume of Copper = 4.84 cm³

Density = 8.95 g/cm³

Considering the expression for density as:

$Density=\frac {Mass}{Volume}$

So,

So, Mass= Density Volume = 8.95 g/cm³ 4.84 cm³ = 43.318 g

Mass of copper = 43.318 g

Molar mass of copper = 63.546 g/mol

The formula for the calculation of moles is shown below:

$moles = \frac{Mass\ taken}{Molar\ mass}$

Thus,

$Moles= \frac{43.318\ g}{63.546\ g/mol}$

Moles of copper = 0.6817 moles

Given, Volume of nitric acid solution = 227 mL = 227 cm³

Density = 1.42 g/cm³

Considering the expression for density as:

$Density=\frac {Mass}{Volume}$

So,

So, Mass= Density Volume = 1.42 g/cm³ 227 cm³ = 322.34 g

Also, Nitric acid is 68.0 % by mass. So,

Mass of nitric acid = $\frac {68}{100}\times 322.34\ g$ = 219.1912 g

Molar mass of nitric acid = 63.01 g/mol

The formula for the calculation of moles is shown below:

$moles = \frac{Mass\ taken}{Molar\ mass}$

Thus,

$Moles= \frac{219.1912\ g}{63.01\ g/mol}$

Moles of nitric acid = 3.4786 moles

According to the reaction,

$Cu_{(s)}+4HNO_3_{(aq)}\rightarrow Cu(NO_3)_2_{(aq)} + 2NO_2_{(g)} + 2H_2O_{(l)}$

1 mole of copper react with 4 moles of nitric acid

Thus,

0.6817 moles of copper react with 4*0.6817 moles of nitric acid

Moles of nitric acid required = 2.7268 moles

Available moles of nitric acid = 3.4786 moles

Limiting reagent is the one which is present in small amount. Thus, nitric acid is present in large amount, copper is the limiting reagent.

The formation of the product is governed by the limiting reagent. So,

1 mole of copper on reaction forms 2 moles of nitrogen dioxide

So,

0.6817 mole of copper on reaction forms 2*0.6817 moles of nitrogen dioxide

Moles of nitrogen dioxide = 1.3634 moles

Given:

Pressure = 724 torr

The conversion of P(torr) to P(atm) is shown below:

$P(torr)=\frac {1}{760}\times P(atm)$

So,

Pressure = 724 / 760 atm = 0.9526 atm

Temperature = 28.2 °C

The conversion of T( °C) to T(K) is shown below:

T(K) = T( °C) + 273.15

So,

T₁ = (28.2 + 273.15) K = 301.35 K

Using ideal gas equation as:

PV=nRT

where,

P is the pressure

V is the volume

n is the number of moles

T is the temperature

R is Gas constant having value = 0.0821 L.atm/K.mol

Applying the equation as:

0.9526 atm × V = 1.3634 mol × 0.0821 L.atm/K.mol × 301.35 K

⇒V = 35.41 L

3 0

3 years ago

What is the name of the isomer with this structural formula?

makkiz [27]

It has 4 pcs of Carbon (C) and 8 pcs of Hydrogen (H) so the formula is C4H8 - calls Butene.
Hope it helps!
#MissionExam001

8 0

4 years ago

An air-filled balloon has a volume of 225 L at 0.940 atm and 25 °C. Soon after, the pressure changes to 0.990 atm and the temper

lorasvet [3.4K]

Answer:

The right choice is V₂ = 195.7 L

Explanation:

We can use the general law of ideal gas: PV = nRT.

where, P is the pressure of the gas in atm.

V: is the volume of the gas in L.

n: is the no. of moles of the gas in mol.

R: is the general gas constant,

T: is the temperature of the gas in K.

If n is constant, and have different values of P, V and T:

(P₁*V₁) / T₁ = (P₂ * V₂) / T₂

Knowing that:

V₁ = 225 L , P₁ = 0.940 atm

T₁ = 25 °C + 273 = 298 K

V₂ = ??? L, P₂ = 0.990 atm

T₂ = 0 °C + 273 = 273 K

applying in the above equation

(P ₁* V₁) / T₁ = (P₂ * V₂) / T₂

(0.940 atm * 225 L) / 298 K= (0.990 atm * V₂) / 273 K

V₂ = (0.940 atm * 225 L * 273 K) / (298 K * 0.990 atm)

V₂ = 195.7 L

So, the right choice is:

V₂ = 195.7 L

7 0

3 years ago