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Un deportista de 72 kg trepa por una cuerda hasta una altura de 12m. Calcula el incremento de energía potencial gravitatoria que

Oxana [17]

A 72 kg athlete climbs a rope to a height of 12m. Calculate the increase in gravitational potential energy it has experienced.

Answer:

8467.2J

Explanation:

Given parameters:

Mass of the athlete = 72kg

Height of the climb = 12m

Unknown:

Increase in gravitational potential energy it has experienced = ?

Solution:

Gravitational potential energy is the energy due to the position of a body. It is mathematically expressed as;

Gravitational potential energy = m x g x h

m is the mass

g is the acceleration due to gravity = 9.8m/s²

h is the height

Insert the parameters and solve;

Gravitational potential energy = 72 x 9.8 x 12

GPE = 8467.2J

4 0

3 years ago

Which one of the following systems has the highest entropy?

Veronika [31]

Answer: a

Explanation:

8 0

3 years ago

Combustion reactions are exothermic. The heat of reaction for the combustion of 2-methylheptane, C8H18, is 1.306×103 kcal/mol. W

WARRIOR [948]

Answer:

11.45kcal/g

2.612 × 10³ kcal

Explanation:

When a compound burns (combustion) it produces carbon dioxide and water. The combustion of 2-methylheptane can be represented by the following balanced equation:

2 C₈H₁₈ + 25 O₂ ⇄ 16 CO₂ + 18 H₂O

It releases 1.306 × 10³ kcal every 1 mol of C₈H₁₈ that is burned.

<em>What is the heat of combustion for 2-methylheptane in kcal/gram?</em>

We know that the molar mass of C₈H₁₈ is 114.0g/mol. Then, using proportions:

$\frac{1.306 \times 10^{3}Kcal}{1mol} .\frac{1mol}{114.0g} =11.45kcal/g$

<em>How much heat will be given off if molar quantities of 2-methylheptane react according to the following equation? 2 C₈H₁₈ + 25 O₂ ⇄ 16 CO₂ + 18 H₂O</em>

In this equation we have 2 moles of C₈H₁₈. So,

$2mol \times\frac{1.306 \times 10^{3}kcal }{1mol} =2.612\times 10^{3}kcal$