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3 years ago

Is the reduction of copper from copper(ii) oxide by carbon exothermic or endothermic? what is the sign of the energy change?

Physics

1 answer:

Sloan [31]3 years ago

8 0

Answer;

-Exothermic reaction;

-The sign of the energy change is negative (-)

Explanation;

2CuO(s) + C(s) --> 2Cu(s) + CO2(g)

ΔH = ΣΔHf(products) - ΣΔHf(reactants)

ΔH = -393.5kJ - 2(-155.2kJ) = -83.1 kJ

The reaction is exothermic.

-An exothermic process or reaction releases heat, causing the temperature of the immediate surroundings to rise. An endothermic process absorbs heat and cools the surroundings.

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Calculate the net force and the acceleration on the block

Darina [25.2K]

Answer:

Net Force = 10N

Acceleration = 2m/s^2

Explanation:

calculate the net force and the acceleration on the block

Net force on the block F = mass * acceleration

Net force acting in the positive direction = 4N + 6N = 10N

Mass = 5kg

According to newton's second law;

a = F/m

a = 10N/5

a = 2m/s^2

hence the acceleration on the block is 2m/s^2

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3 years ago

How far does a boat travel in 5 hours at 32 miles per hour? 162 mi 160 mi 210 mi

sleet_krkn [62]

We know that:
d=vt
d=32mph*5h
d=160mi

4 0

3 years ago

Read 2 more answers

A 55.0-g sample of hot metal initially at 99.5oC was added to 40.0 g of water in a Styrofoam coffee cup calorimeter. The water a

Kaylis [27]

Answer:

Cp= 0.44 J/g.C

This is heat capacity of metal.

Explanation:

From energy conservation

Heat lost by metal = Heat gain by water +Heat gain by calorimeter

Because here temperature of metal is high that is why it loose the heat.The temperature of water and calorimeter is low that is why they gain the heat.

final temperature is T= 30.5 C

We know that sensible heat transfer given as

Q= m Cp ΔT

m=Mass

Cp=Specific heat capacity

ΔT=Temperature difference

By putting the values

55 x Cp ( 99.5 - 30.5) = 40 x 4.184 ( 30.5- 21 ) + 10 x ( 30.5 - 21)

Cp ( 99 .5- 30.5) = 30.65

Cp= 0.44 J/g.C

This is heat capacity of metal.

4 0

3 years ago

Squids and octopuses propel themselves by expelling water. They do this by keeping water in a cavity and then suddenly contracti

liq [111]

Answer:

The speed of water must be expelled at 6.06 m/s

Explanation:

Neglecting any drag effects of the surrounding water we can assume the linear momentum in this case is conserves, that is, the total initial momentum of the octopus and the water kept in it cavity should be equal to the total final linear momentum. That's known as conservation of momentum, mathematically expressed as:

$p_f=p_i$

with Pi the total initial momentum and Pf the final total momentum. The total momentum is the sum of the momentums of the individual objects, in our case the octopus and the mass of water that will be expelled:

$p_{of}+p_{wf}=p_{oi}+p_{wi}$

with Po the momentum of the octopus and Pw the momentum of expelled water. Linear momentum is defined as mass times velocity:

$m_o*v_{of}+m_w*v_{wf}=m_o*v_{oi}+m_w*v_{wi}$

Note that initially the octopus has the water in its cavity and both are at rest before it sees the predator so $v_{oi}=v_{wi} = 0\frac{m}{s}$ :

$m_o*v_{of}+m_w*v_{wf}=0$

We should find the final velocity of water if the final velocity of the octopus is 2.70 m/s, solving for $v_{wf}$ :

$v_{wf}=-\frac{m_o*v_{of}}{m_w}=-\frac{(6.00-1.85)*(2.70)}{1.85}$

$v_{wf}=-6.06\frac{m}{s}$

The minus sign indicates the velocity of the water is opposite the velocity of the octopus.

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3 years ago

What is the source of the radioactive nuclei present in spent fuel rods?

Debora [2.8K]

The answer is nuclear fission. The source of the radioactive nuclei present in spent fuel rods is nuclear fission. Nuclear fission is the process in which a large nucleus splits into two smaller nuclei with the release of energy.

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3 years ago