The engine ran for 10 second
<h3>
Answer:</h3>
915 Joules
<h3>
Explanation:</h3>
- The heat of fusion is the heat that is required to convert a given mass of a substance from solid state to liquid state without change in temperature.
- In this case, we are given specific heat of a substance as 122 joules per gram
- It means that amount of heat equivalent to 122 joules is required to change 1 gram of the substance from solid state to liquid state.
- Therefore, we can determine the amount of heat needed to change 7.5 grams of the substance from solid to liquid state.
1 g = 122 Joules
7.5 g = ?
= 122 × 7.5
= 915 Joules
Thus, 7.5 g of the substance at its melting point will require 915 Joules of heat to melt.
<h3>
Answer:</h3>
A. 860 kg
<h3>
Explanation:</h3>
To answer the question we need to understand that;
- Mass refers to the amount of matter in an object.
- Weight, on the other hand, refers to the gravitational pull of an object to a given surface.
- Mass is measured using a spring balance.
We also need to know that;
- The mass of an object remains constant every where irrespective of the gravitational acceleration.
- Therefore, an object on the surface of the earth would have the same mass as on the surface of the moon.
- In this case; the mass of the car remains the same on the outer space as on the back yard.
Molar mass:
O2 = 16 x 2 = 32.0 g/mol Mg = 24 g/mol
<span>2 Mg(s) + O2(g) --->2 MgO(s)
</span>
2 x 24.0 g Mg -------------> 32 g O2
5.00 g Mg -----------------> ( mass of O2)
mass of O2 = 5.00 x 32 / 2 x 24.0
mass of O2 = 160 / 48
= 3.33 g of O2
hope this helps!
