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:
357.6g
Explanation:
Given parameters:
Density = 12.459g/cm³
Volume of metal = 28.7cm³
Unknown:
Mass of metal = ?
Solution:
The density of a substance is its mass per unit volume.
To find the mass;
Mass of metal = density x volume
Now insert the parameters and solve;
Mass of metal = 12.459 x 28.7 = 357.6g
The sun is the centre of our solar system
Answer:
Say a 14 year old girl was at a construction site and she was asked to move something like a 10,000 pound brick( one brick). She would be acting on it as the unbalanced force but they would still not change their position.
so to say the girl would be doing everything she could to move that brick but the brick would still be in that same spot so the unbalanced force (the girl) would be acting on the thing that was at rest but it wouldn't move.
so the unbalanced force would not really be acting on the thing at rest; even though the unbalanced force was doing something to the brick.
( just think about it and you will eventually get it...just imagine in your head...)
Explanation:
Answer:

Explanation:
Given:
- mass of the object on a horizontal surface,

- coefficient of static friction,

- coefficient of kinetic friction,

- horizontal force on the object,

<u>Now the value of limiting frictional force offered by the contact surface tending to have a relative motion under the effect of force:</u>

where:
normal force of reaction acting on the body= weight of the body


As we know that the frictional force acting on the body is always in the opposite direction:
So, the frictional force will not be at its maximum and will be equal in magnitude to the applied external force and hence the body will not move.
so, the frictional force will be:
