Random errors will shift each measurement from its true value by a random amount and in a random direction. These will affect reliability (since they're random) but may not affect the overall accuracy of a result.
Disadvantages of aluminum in building cars include:
On average, aluminum is more expensive than steel, as much as two to three times.
Aluminum is not easily welded. If a steel door or panel suffers a crack, often it cam be welded back together easily, primed and repainted so its difficult to tell any body work has been performed. This cannot be done with aluminum. Steel also can be bent and shaped as needed.
Body shops and even dealer service centers are currently equipped for steel work with technicians skilled in the art of welding and steel fabrication. The cost of switching over to an infra structure designed specifically for all-aluminum vehicles or mass production of aluminum vehicles and components would be high.
Charge of nucleus is always positive whether it is element or isotope.
As long as the equation in question can be expressed as the sum of the three equations with known enthalpy change, its 
can be determined with the Hess's Law. The key is to find the appropriate coefficient for each of the given equations.
Let the three equations with given be denoted as (1), (2), (3), and the last equation (4). Let 
, 
, and 
be letters such that 
. This relationship shall hold for all chemicals involved.
There are three unknowns; it would thus take at least three equations to find their values. Species present on both sides of the equation would cancel out. Thus, let coefficients on the reactant side be positive and those on the product side be negative, such that duplicates would cancel out arithmetically. For instance, 
shall resemble the number of 
left on the product side when the second equation is directly added to the third. Similarly
Thus
and
Verify this conclusion against a fourth species involved- 
for instance. Nitrogen isn't present in the net equation. The sum of its coefficient shall, therefore, be zero.
Apply the Hess's Law based on the coefficients to find the enthalpy change of the last equation.
Van der waals force
Explanation:
The intermoleclular forces are attraction between molecules. Interatomic forces are attraction between atoms in a compound.
In most hydrocarbons the weak Van der waals attraction are known.
- These forces are weak attraction joining non-polar and polar molecules together.
- These forces can also be found in layers of graphite.
- They are of two types;
London dispersion forces are attraction that exists between non-polar molecules and the noble gas.
Dipole - Dipole attractions are forces of attraction existing in polar molecules.
In hydrocarbons, we have non-polar molecules and intermolecular attraction is london dispersion forces.
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Intermolecular forces brainly.com/question/10107765
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