Answer:
Answer for the question is given in the attachment.
Explanation:
1). Take a sample of the substance. The sample should be the largest
possible that will allow it to be be easily handled and the following steps
to be performed with it.
(The density doesn't depend on the size of the sample, and every sample
of the same substance has the same density. But using a larger sample
can improve the accuracy of the measurements you make, and therefore
improve the accuracy of the density you derive for the substance.)
2). Ask or measure the mass of the sample.
3). Ask or measure the volume of the sample.
4). Divide the mass by the volume. Their quotient is the density
of the substance.
Answer:
d) 0 V
Explanation:
It can be showed that the potential due to a point charge q, to a distance d from the charge, can be expressed as follows:
where k = 
As the potential is an scalar, and is linear with the charge, we can apply the superposition principle, which means that we can find the potential due to one of the charges, as if the other were not present.
By symmetry, all four charges are at the same distance from the center, so we can write the total potential, as follows:
where d, is the semi-diagonal of the square, that we can find applying Pythagorean theorem, as follows:
Replacing by the values in (1) we have:
which is equal to the option d).
Answer:
B) PbI2 + 2 KCl
Explanation:
To keep the the law of conservation of matter, the equation given above must be balanced i.e the total element in the reactant must be equal to the total elements in the product.
Given the equation
PbCl2 (aq) + 2 KI (aq) →
At the reactant shown, there are one mole of lead Pb, 2 moles of chlorine Cl, 2moles of Potassium K and 2 moles of Iodine.
During reaction, the Chlorine atom will react with the potassium atom K and the lead atom Pb will react with the iodine atom.
The resulting product that will balance the chemical equation is
PbI2 + 2 KCl
The equation will then become
PbCl2 (aq) + 2 KI (aq) → PbI2 + 2 KCl
If we look at both sides of the equation, we will see that all the elements have the same number of atoms.
The net force on the box parallel to the plane is
∑ F[para] = mg sin(24°) = ma
where mg is the weight of the box, so mg sin(24°) is the magnitude of the component of its weight acting parallel to the surface, and a is the box's acceleration.
Solve for a :
g sin(24°) = a ≈ 3.99 m/s²
The box starts at rest, so after 7.0 s it attains a speed of
(3.99 m/s²) (7.0 s) ≈ 28 m/s
