Answer:
molecular formula =
Explanation:
Given data
c = 92.25%
H = 7.75%
molar mass = 104 g/mol
to find out
the empirical and molecular formula for styrene
solution
we know that
styrene 1 g contain = 0.9225 g C and 0.0775 g H
so
C = 104 × 0.9225 g / 12 g/mol
C = 7.995 mol = approx 8 mol
and
H = 104 × 0.0775 g / 1 g/mol
H = 8.06 mol = approx 8 mol
so we say that 1 mole of styrene have 8 mole of C and H
so
molecular formula =
Answer:
11.7 s
Explanation:
In this problem, the rocket is moving in a uniform accelerated motion. We have the following data:
d = 223 m, the distance that the sled has to cover
, the acceleration of the rocket
We can use therefore the following SUVAT equation:
where
d is the distance
u = 0 is the initial velocity of the sled (it starts from rest)
t is the time
a is the acceleration
Re-arranging the equation and substituting the numbers, we find the time it takes for the rocket to cross the field:
The ducks' flight path as observed by someone standing on the ground is the sum of the wind velocity and the ducks' velocity relative to the wind:
ducks (relative to wind) + wind (relative to Earth) = ducks (relative to Earth)
or equivalently,
(see the attached graphic)
We have
Then by setting components equal, we have
We only care about the direction for this question, which we get from the first equation:
or approximately 136º or 224º.
Only one of these directions must be correct. Choosing between them is a matter of picking the one that satisfies <em>both</em> equations. We want
which means <em>θ</em> must be between 180º and 360º (since angles in this range have negative sine).
So the ducks must fly (relative to the air) in a direction 224º relative to the positive horizontal direction, or about 44º South of West.
