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3 years ago

20 POINTS What is an endothermic reaction?

Physics

2 answers:

Ratling [72]3 years ago

7 0

Answer:

An endothermic reaction is a chemical reaction in which more energy is needed to break bonds in the reactants than is released when new bonds form in the products.

A constant input of energy, often in the form of heat, is needed to keep an endothermic reaction going.

Explanation:

A would be the answer

tiny-mole [99]3 years ago

3 0

Answer:

A reaction that contributes energy to the surroundings

Explanation:

When energy is taken in from the Surroundings, the temperature of the surroundings decreases

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As you may well know, placing metal objects inside a microwave oven can generate sparks. Two of your friends are arguing over th

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Answer:

$4.048\times 10^{-7}\ m$

Explanation:

h = Planck's constant = $6.626\times 10^{-34}\ m^2kg/s$

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$\lambda=\dfrac{hc}{E}\\\Rightarrow \lambda=\dfrac{6.626\times 10^{-34}\times 3\times 10^8}{4.91\times 10^{-19}}\\\Rightarrow \lambda=4.048\times 10^{-7}\ m$

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3 years ago

A rocket of mass 1000kg uses 5kg of fuel and oxygen to produce exhaust gases ejected at 500m/s calculate the increase its veloci

Vlad [161]

Answer:

Approximately $\rm 2.5\; m \cdot s^{-1}$ .

Explanation:

Let the increase in the rocket's velocity be $\Delta v$ . Let $v_0$ represent the initial velocity of the rocket. Note that for this question, the exact value of $v_0$ doesn't really matter.

The momentum of an object is equal to its mass times its velocity.

Mass of the rocket with the 5 kg of fuel: $1000$ .
Initial velocity of the rocket and the fuel: $v_0$ .
Hence the initial momentum of the rocket: $1000\,v_0$ .

Mass of the rocket without that 5 kg of fuel: $1000 - 5 = 995$ .
Final velocity of the rocket: $v_0 + \Delta v$ .
Hence the final momentum of the rocket: $995\,(v_0 + \Delta v)$ .

Mass of the 5 kg of fuel: $5$ .
Final velocity of the fuel: $v_0 - 500$ (assuming that the the 500 m/s in the question takes the rocket as its reference.)
Hence the final momentum of the fuel: $5\,(v_0 - 500)$ .

Momentum is conserved in an isolated system like the rocket and its fuel. That is:

Sum of initial momentum = Sum of final momentum.

$1000\,v_0 = 995\,(v_0 + \Delta v) + 5\,(v_0 - 500)$ .

Note that $1000\, v_0$ appears on both sides of the equation. These two terms could hence be eliminated.

$0 = 995\, \Delta v - 5\times 500$ .

$\displaystyle \Delta v = \frac{5}{995}\times 500 \approx \rm 2.5\; m \cdot s^{-1}$ .

Hence, the velocity of the rocket increased by around 2.5 m/s.

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3 years ago

How much energy is received by earth per second per unit area ?

Hunter-Best [27]

Answer:

The approximate average value cited, 1.3608 ± 0.0005 kW/m², which is 81.65 kJ/m² per minute, is equivalent to approximately 1.951 calories per minute per square centimeter, or 1.951 langleys per minute.

Explanation:

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20 POINTS What is an endothermic reaction?​

20 POINTS What is an endothermic reaction?