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3 years ago

What causes eclipses? Check all that apply.

Chemistry

2 answers:

pickupchik [31]3 years ago

8 0

The moon moves in front of the sun

Roman55 [17]3 years ago

6 0

Answer:

An eclipse happens when one astronomical body blocks light from or to another.

Explanation:

The Moon moves into the shadow of Earth cast by the Sun. When the Moon passes through the outer part of Earth’s shadow—the penumbra, where the light of the Sun is only partly extinguished—the Moon dims only slightly in what is called a penumbral eclipse. When the Moon passes through the central part of Earth’s shadow—the umbra, where the direct light of the Sun is totally blocked—the lunar eclipse is considered partial if the Moon is partly within the umbra or total if the Moon is completely within it.

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Is mixing baking soda and vegetable oil a chemical change or physical change and WHY? PLEASE HELP

skelet666 [1.2K]

It’s a chemical change

3 0

2 years ago

Read 2 more answers

Calculate the initial rate for the formation of C at 25 ∘C, if [A]=0.50M and [B]=0.075M.Express your answer to two significant f

N76 [4]

The question is incomplete, here is the complete question:

Calculate the initial rate for the formation of C at 25°C, if [A]=0.50 M and [B]=0.075 M. Express your answer to two significant figures and include the appropriate units.Consider the reaction

A + 2B ⇔ C

whose rate at 25°C was measured using three different sets of initial concentrations as listed in the following table:

The table is attached below as an image.

Answer: The initial rate for the formation of C at 25°C is $2.25\times 10^{-2}Ms^{-1}$

Explanation:

Rate law is defined as the expression which expresses the rate of the reaction in terms of molar concentration of the reactants with each term raised to the power their stoichiometric coefficient of that reactant in the balanced chemical equation.

For the given chemical equation:

$A+2B\rightleftharpoons C$

Rate law expression for the reaction:

$\text{Rate}=k[A]^a[B]^b$

where,

a = order with respect to A

b = order with respect to B

Expression for rate law for first trial:

$5.4\times 10^{-3}=k(0.30)^a(0.050)^b$ ....(1)

Expression for rate law for second trial:

$1.1\times 10^{-2}=k(0.30)^a(0.100)^b$ ....(2)

Expression for rate law for third trial:

$2.2\times 10^{-2}=k(0.50)^a(0.050)^b$ ....(3)

Dividing 2 by 1, we get:

$\frac{1.1\times 10^{-2}}{5.4\times 10^{-3}}=\frac{(0.30)^a(1.00)^b}{(0.30)^a(0.050)^b}\\\\2=2^b\\b=1$

Dividing 3 by 1, we get:

$\frac{2.2\times 10^{-2}}{5.4\times 10^{-3}}=\frac{(0.50)^a(0.050)^b}{(0.30)^a(0.050)^b}\\\\4.07=2^a\\a=2$

Thus, the rate law becomes:

$\text{Rate}=k[A]^2[B]^1$ ......(4)

Now, calculating the value of 'k' by using any expression.

Putting values in equation 1, we get:

$5.4\times 10^{-3}=k[0.30]^2[0.050]^1\\\\k=1.2M^{-2}s^{-1}$

Calculating the initial rate of formation of C by using equation 4, we get:

$k=1.2M^{-2}s^{-1}$

[A] = 0.50 M

[B] = 0.075 M

Putting values in equation 4, we get:

$\text{Rate}=1.2\times (0.50)^2\times (0.075)^1\\\\\text{Rate}=2.25\times 10^{-2}Ms^{-1}$

Hence, the initial rate for the formation of C at 25°C is $2.25\times 10^{-2}Ms^{-1}$

8 0

3 years ago

A or B i need help fast

Bezzdna [24]

Answer: I would go with B

Explanation: The motor in a circuit isn't moving. That's very vague, but it doesn't show any evidence that an electrical current is going through it, likewise it doesn't show that an electrical current ISN'T going through it. However in regards to this question I would go with B.

5 0

3 years ago

What actions affect blood pH

galben [10]

Integestion, vomiting, diarrhea, lung function, endocrine function, kidney function

4 0

3 years ago

If you start a chemical reaction with 5 atoms of hydrogen, how many hydrogen atoms will you have when it is finished? Group of a

mote1985 [20]

Answer:

5 atoms

Explanation:

According to the law of conservation of mass, "matter is neither created nor destroyed in the cause of a chemical reaction".

We finish with what we start with in a chemical reaction. Although new species might form, the number of atoms on both sides of the expression will still be maintained.

All chemical reactions obey this law of conservation.

8 0

3 years ago