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3 years ago

What are these smooth, distinct layers most directly evidence of ?

2 answers:

8 0

Answer: The layers of the rocks in one region of the parks are smooth and distinct, which are evidence of many, many years of deposition. The layers on the rocks are because of different deposition of sediments. Different sediments deposited over the rocks through wind, water and ice over the ages

Hope we helped alot! :)

Neko [114]3 years ago

5 0

Explanation:

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Each molecule of testosterone contains 19 atoms of carbon (plus other atoms). The mass percent of carbon in testosterone is 79.1

Xelga [282]

Answer:

The answer to your question is letter E. 288.4 g/mol

Explanation:

Data

Number of carbons = 19

mass percent of carbon = 79.12

molar mass = ?

Process

1.- Calculate the molar mass of 19 atoms of carbon

Atomic mass of carbon = 12 g

Atomic mass of 19 atoms of carbon = 228 g

2.- Use proportions to calculate the mass of testosterone

228 g --------------- 79.12 %

x -------------- 100 %

x = (228 x 100) / 79.12

Simplify

x = 22800 / 79.12

Molar mass of testosterone = 288.2 g

6 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

answer last one “How many moles of hydrogen are consumed to produce 100 g ammonia” ? explanation and answer required then u get

SVETLANKA909090 [29]

Answer:

The answer is 17.03052. We assume you are converting between grams Ammonia and mole.

4 0

3 years ago

In what industry do fertilizers and pesticides wash off and contaminate water supplies?Construction Oil Transportation Agricultu

KIM [24]

Answer:

The answer is agriculture.

Explanation:

3 0

3 years ago

Mg + 2HCl ⟶ MgCl2 + H2

Ivanshal [37]

Answer: m = 24.31 g/mol · 1.13 mol

Explanation: 2 mol HCl use 1 mol Mg.

Magnesium is used 0.5 · 2.26 mol = 1.13 mol

M(Mg) = 24.31 g/ mol

7 0

3 years ago