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3 years ago

ANYONE THATS GOOD WITH CHEMISTRY PLEASE HELP!

Chemistry

1 answer:

sergejj [24]3 years ago

5 0

CH2O. You can reduce 8, 16, and 8 to 1, 2, and 1. You just simplify the numbers. When there is no number after an element, it means that there is one of them.

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2 N H 3 ( g ) ⟷ N 2 ( g ) + 3 H 2 ( g ) K p = 0.83 Consider your answers above, if the initial pressures for all three species i

OlgaM077 [116]

Explanation:

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5 0

3 years ago

Write a balanced equation for the combustion of C7H16(l) (heptane) -- i.e. its reaction with O2(g) forming the products CO2(g) a

JulsSmile [24]

Answer:

The standard enthalpy of reaction = -4854.7kJ

The difference: ΔH-ΔE = Δ(PV) = Δn.R.T = 9910.288 J ≈ 9.91 kJ

Explanation:

The balanced chemical equation for the combustion of heptane:

C₇H₁₆ (l) + 11 O₂ (g) → 7 CO₂ (g) + 8 H₂O (l)

Given: The standard enthalpy of formation ( $\Delta H _{f}^{\circ }$ ) for: C₇H₁₆ (l) = -187.8 kJ/mol, O₂ (g) = 0 kJ/mol, CO₂ (g) = -393.5 kJ/mol, H₂O (l) = -286 kJ/mol

To calculate the standard enthalpy of reaction ( $\Delta H _{r}^{\circ }$ ) can be calculated by the Hess's law:

$\Delta H _{r}^{\circ } = \left [\sum \nu \cdot\Delta H _{f}^{\circ }(products) \right ] - \left [\sum \nu\cdot\Delta H _{f}^{\circ }(reactants) \right ]$

Here, $\nu$ is the stoichiometric coefficient

⇒ $\Delta H _{r}^{\circ } =$

$\left [ 7\times \Delta H _{f}^{\circ }\left (CO_{2}\right )+ 8\times \Delta H _{f}^{\circ }\left (H_{2}O \right )\right ]$

$- \left [1\times \Delta H _{f}^{\circ }\left (C_{7}H_{16}\right ) +11\times \Delta H _{f}^{\circ }\left (O_{2} \right ) \right ]$

$=\left [ 7\times \left (-393.5 kJ/mol \right )+ 8\times \left (-286 kJ/mol \right )\right ]$

$-\left [1\times \left (-187.8 kJ/mol \right ) +11\times \left (0 kJ/mol \right ) \right ]$

⇒ $\Delta H _{r}^{\circ } = \left [ \left (-2754.5 \right )+ \left (-2288 \right )\right ]\left -[ \left (-187.8 \right ) +\left (0 \right )\right ]$

⇒ $\Delta H _{r}^{\circ } = \left [ -5042.5 ]\left -[ -187.8] = \left ( -4854.7kJ \right )$

To calculate the difference: ΔH-ΔE=Δ(PV)

We use the ideal gas equation: P.V = n.R.T

⇒ ΔH-ΔE=Δ(PV) = Δn.R.T

Given: Temperature:T = 298K, R = 8.314 J⋅K⁻¹⋅mol⁻¹

Δn = number of moles of gaseous products - number of moles of gaseous reactants = (7)- (11) = (-4)

⇒ ΔH-ΔE=Δ(PV) = Δn.R.T = (-4 mol) × (8.314 J⋅K⁻¹⋅mol⁻¹) × (298K) = 9910.288 J = 9.91 kJ (∵ 1 kJ = 1000J )

8 0

3 years ago

What mass of calcium hydroxide is formed when 10.0g of calcium oxide reacts with 10.0g of water?

nexus9112 [7]

The mass of calcium hydroxide that is formed when 10.0 g of CaO reacts with 10.0 g of water is 13.024 grams

calculation

from the equation

CaO + H2O → Ca(OH)2,

1 moles of CaO reacted with 1 moles of H2O to form 1 moles of Ca(OH)2

find the moles of each reactant

moles=mass/molar mass

moles of CaO= 10 g/56 g/mol=0.179 moles

moles of H2O = 10 g/18 g/mol 0.556 moles

CaO is the limiting reagent therefore by use of mole ratio of CaO:Ca(OH)2 which is 1:1 moles of Ca(OH)2 is = 0.179 moles

mass= moles x molar mass

= 0.176 moles x 74 g/mol = 13.024 grams

7 0

3 years ago

If 7.0 mol of NO and 5.0 mol of O2 are reacted tegethor. The reaction generates 3.0 mol of NO2. What is the percent yield for th

Daniel [21]

Answer:

Percentage yield = 30%

Explanation:

Given data:

Number of moles of NO = 7.0 mol

Number of moles of O₂ = 5 mol

Number of moles of NO₂ = 3 mol

Percentage yield = ?

Solution:

Chemical equation:

2NO + O₂ → 2NO₂

Now we will compare the moles of NO₂ with NO and O₂ .

NO : NO₂

2 : 2

7.0 : 7.0

O₂ : NO₂

1 : 2

5.0 : 2 ×5.0 = 10 mol

The number of moles of NO₂ produced by NO are less it will be limiting reactant.

Mass of NO₂ = moles × molar mass

Mass of NO₂ = 10 mol × 46g/mol

Mass of NO₂ = 460 g

Actual yield of NO₂:

Mass of NO₂ = moles × molar mass

Mass of NO₂ = 3 mol × 46g/mol

Mass of NO₂ = 138 g

Percentage yield:

Percentage yield = Actual yield/theoretical yield × 100

Percentage yield = 138 g/ 460 g × 100

Percentage yield = 30%

5 0

3 years ago

The properties of matter depend on the types of atoms a substance is made of. true of false?

Irina18 [472]

False pls mark brainliest

4 0

3 years ago

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