Ask question

Ask question

All categories

3 years ago

14

Which of the following best describes what causes the phases of the moon? The alignment of the sun, Earth, and moon The speed of

the moon around the Earth The speed of the Earth around the sun The alignment of the planets

1 answer:

BlackZzzverrR [31]3 years ago

6 0

The alignments of the planets would be the correct answer.<span />

You might be interested in

A certain first-order reaction (A→products) has a rate constant of 8.10×10−3 s−1 at 45 ∘C. How many minutes does it take for the

stira [4]

Answer:

The answer is 5.7 minutes

Explanation:

A first-order reaction follow the law of $Ln [A] = -k.t + Ln [A]_{0}$ . Where <em>[A]</em> is the concentration of the reactant at any <em>t</em> time of the reaction, $[A]_{0}$ is the concentration of the reactant at the beginning of the reaction and <em>k</em> is the rate constant.

Dropping the concentration of the reactant to 6.25% means the concentration of A at the end of the reaction has to be $[A]=\frac{6.25}{100}.[A]_{0}$ . And the rate constant (<em>k</em>) is 8.10×10−3 s−1

Replacing the equation of the law:

$Ln \frac{6.25}{100}.[A]_{0} = -8.10x10^{-3}s^{-1}.t + Ln[A]_{0}$

Clearing the equation:

$Ln [A]_{0}.\frac{6.25}{100} - Ln [A]_{0} = -8.10x10^{-3}s^{-1}.t$

<em>Considering the property of logarithms: </em> $Ln A - Ln B = Ln \frac{A}{B}$

Using the property:

$Ln \frac{[A]_{0}}{[A]_{0}}.\frac{6.25}{100} = -8.10x10^{-3}s^{-1}.t$

Clearing <em>t </em>and solving:

$t = \frac{Ln \frac{6.25}{100} }{-8.10x10^{-3}s^{-1} } = 342.3s$

The answer is in the unit of seconds, but every minute contains 60 seconds, converting the units:

$342.3x\frac{1min}{60s} = 5.7min$

6 0

3 years ago

Which is radioactive decay

Liula [17]

Answer:

Explanation:all

7 0

3 years ago

The absorption spectrum of a molecular compound in the microwave radiation range provides information about the: 1.Electronic st

Virty [35]

Answer: 2. Bonds and bond energies of the molecule

Explanation:

The absorption spectrum is an electromagnetic spectrum which is used for observing the intensity of the radiations which have been absorbed by the substances shown by the pattern of dark lines or bands. Infrared and microwave spectroscopy are specialized techniques which are used for observing the bonds and bond energy of the molecules which can be observed by measuring the frequencies at which the radiations are absorbed.

5 0

3 years ago

Suppose the mole number of Ca2+ ions in a 50 mL water sample is quantified as 1.5 × 10−5 mol. What is the concentration of Ca2+

Anna11 [10]

$\frac{1.5x 10^{-5} mol Ca^{2+}}{50ml} ( \frac{1 mol CaC O_{3} }{1 mol Ca^{2+} } )( \frac{100,000 ppm}{1 molCaC O_{3}/L } ) \\ =0.0300234$

5 0

3 years ago

Read 2 more answers

How many atoms are in 0.0303 mol K?

Inga [223]

1.661x10 negative 24 squared

8 0

3 years ago