Answer:
Q (reaction) = -69.7 kJ
Explanation:
Octane reacts with oxygen to give carbon dioxide and water.
C₈H₁₈ + 25 O₂ ---> 16 CO₂ +18 H₂O
This reaction is exothermic in nature. Therefore, the energy is released into the atmosphere. This reaction took place in a calorimeter, there the temperature (T) increases by 10 C. The heat capacity of the calorimeter is 6.97 kJ/C
The heat (q) of the reaction is calculated as follows:
Q= -cT, where c is the heat capacity of the calorimeter and T is the increase in temperature
q = -(6.97) x (10) = -69.7kJ
<em>Since the heat capacity is given in kilo -joule per degree Celsius, therefore, the mass of octane is not required </em>
Answer:
The value is 
Explanation:
From the question we are told that
The velocity is
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The time taken is 
The time taken for contact is 
The velocity of the of the car after contact is
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From the equation of kinematics we have that

Here u = 0 \ m/s since the car is initially motionless
=> 
=> 
Answer:
d = 175 miles
Explanation:
Train is moving towards East with constant speed of 50 mph
While car is moving at speed of 30 mph
so after t = 3 hours
the distance moved by the train is given as


at the same time the distance moved by the car is given as

now we know that both car and train is moving perpendicular to each other
So the distance between them after t = 3 hours is given as



Answer:
mechanical
Explanation:
the energy is carried by water <3 hope this helped
Answer:
Less than a quarter of Earth's surfaces are dry, ice free lands