The suggestion is to prevent a puddle of the liquid present in the sample from forming or from it leaking on to the surface on which it is placed. For example, if precipitates of a solid are removed from water and then placed on filter paper to dry, the water will soak into the filter paper and then leak on to the counter on which it is placed. If this precipitate were placed in a watch glass or weighing paper, the water would only evaporate and would not contaminate the sample.
You can tell if each side of the equation has the same molar mass.
Answer:
(b). Mass and distance.
Explanation:
The gravitational force between two objects is given by Newton's law of universal gravitation. The formula is as follows :
Here,
G is universal gravitational constant
r is the distance between two objects
It is very clear that the gravitational force is directly proportional to the product of masses and inversely proportional to the square of the distance between them.
Hence, the two quantities are used to predict gravitational force according to Newton's law of universal gravitation are mass and distance.
Answer:
120g
Explanation:
We'll begin by writing the balanced equation for the reaction. This is given below:
Sn + 2HF —> SnF2 + H2
Next, we shall determine the number of mole of HF needed to react with 3 moles of Sn.
From the balanced equation above, 1 mole of Sn reacted with 2 moles of HF.
Therefore, 3 moles of Sn will react with = 3 x 2 = 6 moles of HF.
Finally, we shall convert 6moles of HF to grams
This is illustrated below:
Number of mole of HF = 6moles
Molar Mass of HF = 1 + 19 = 20g/mol
Mass of HF =..?
Mass = number of mole x molar Mass
Mass of HF = 6 x 20
Mass of HF = 120g
Therefore, 120g of HF is needed to react with 3 moles of Sn
Answer:
length of wire = 38.82 m
Explanation:
∴ 16 gauge ≡ 0.05082 in * ( 2.54 cm/in ) = 0.12908 cm
∴ m spool = 1 Lb = 453.592 g
∴ ρ = 8.92 g/cm³
cross section area:
⇒ A = π*D²/4 = π*(0.12908)²/4 = 0.0131 cm²
⇒ L = ((453.592 g) *(cm³/8.92 g)) / ( 0.0131 cm² )
⇒ L = 3881.765 cm * ( m/100cm) = 38.82 m
