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3 years ago

Which change in the environment led to more dark-colored peppered moths?

Chemistry

2 answers:

andriy [413]3 years ago

8 0

Answer:

Explanation:

Peppered moths were originally more white in coloring due to needing to be able to blend into the trees. But during the industrial revolution, more smog and soot was being produced, causing the trees to become more black in color, making it harder for the moths to blend in. Therefore, resulting in the need for genetic mutations within the moths to help them better blend into their surroundings to avoid predators. (I just recently took this test too)

Hope this helps :)

zlopas [31]3 years ago

5 0

Answer:

Explanation:

if there is more dark soot, then there is more of a chance that they won't be seen

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Which three statements about gravity and the formation of the solar system

Delicious77 [7]

Answer:

B. Gravity held the pieces of forming planets together.

c. Gravity pulled most of the matter into the center of the solar system

D. Gravity caused the planets and Sun to have spherical shapes.

Explanation:

When a collection of grains pulled together by their gravitational forces would keep in by the gravity of a star, it would eventually became bigger to the point a planet was formed.

The sun's strong gravitational force pulled most of the matter around it to the center of the solar system.

The spherical shape of planets is a result of their gravity pulling equally from all sides, shaping it into a sphere.

7 0

3 years ago

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Balance this equation: Ca(OH)2 + HCI → CaCl2 + H20

Verizon [17]

Answer:

Double Displacement (Acid-Base)

Explanation:

5 0

3 years ago

Copper(II) sulfide is formed when copper and sulfur are heated together. In this reaction,

storchak [24]

Answer:

The mass of copper(II) sulfide formed is:

= 81.24 g

Explanation:

The Balanced chemical equation for this reaction is :

$Cu(s) + S\rightarrow CuS$

given mass= 54 g

Molar mass of Cu = 63.55 g/mol

$Moles = \frac{given\ mass}{Molar\ mass}$

$moles=\frac{54}{63.55}$

Moles of Cu = 0.8497 mol

Given mass = 42 g

Molar mass of S = 32.06 g/mol

$Moles = \frac{given\ mass}{Molar\ mass}$

$moles=\frac{42}{32.06}$

Moles of S = 1.31 mol

Limiting Reagent : The reagent which is present in less amount and consumed in a reaction

First find the limiting reagent :

$Cu + S\rightarrow CuS$

1 mol of Cu require = 1 mol of S

0.8497 mol of Cu should require = 1 x 0.8497 mol

= 0.8497 mol of S

S present in the reaction Medium = 1.31 mol

S Required = 0.8497 mol

S is present in excess and Cu is limiting reagent

All Cu is consumed in the reaction

Amount Cu will decide the amount of CuS formed

$Cu + S\rightarrow CuS$

1 mole of Cu gives = 1 mole of Copper sulfide

0.8497 mol of Cu = 1 x 0.8497 mole of Copper sulfide

= 0.8497

Molar mass of CuS = 95.611 g/mol

$Moles = \frac{given\ mass}{Molar\ mass}$

$0.8497 = \frac{given\ mass}{95.611}$

Mass of CuS = 0.8497 x 95.611

= 81.24 g

3 0

4 years ago

The equilibrium constant Kc for the decomposition of phosgene, COCl2, is 4.63x10^-3 at 527 C. Calculate the equilibrium partial

Studentka2010 [4]

Answer: The partial pressure of the $CO,Cl_2\text{ and }COCl_2$ are 0.352 atm, 0.352 atm and 0.408 atm respectively.

Explanation:

We are given:

$K_c=4.63\times 10^{-3}$

$p_{COCl_2}=0.760atm$

Relation of $K_p$ with $K_c$ is given by the formula:

$K_p=K_c(RT)^{\Delta ng}$

Where,

$K_p$ = equilibrium constant in terms of partial pressure = ?

$K_c$ = equilibrium constant in terms of concentration = $4.63\times 10^{-3}$

R = Gas constant = $0.0821\text{ L atm }mol^{-1}K^{-1}$

T = temperature = $527^oC=527+273=800K$

$\Delta ng$ = change in number of moles of gas particles = $n_{products}-n_{reactants}=2-1=1$

Putting values in above equation, we get:

$K_p=4.63\times 10^{-3}\times (0.0821\times 800)^{1}\\\\K_p=0.304$

The chemical reaction for the decomposition of phosgene follows the equation:

$COCl_2(g)\rightleftharpoons CO(g)+Cl_2(g)$

At t = 0 0.760 0 0

At $t=t_{eq}$ 0.760-x x x

The expression for $K_p$ for the given reaction follows:

$K_p=\frac{p_{CO}\times p_{Cl_2}}{p_{COCl_2}}$

We are given:

$K_p=0.304\\p_{COCl_2}=0.760-x\\p_{CO}=x\\p_{Cl_2}=x$

Putting values in above equation, we get:

$0.304=\frac{x\times x}{0.760-x}\\\\x=0.352,-0.656$

Negative value of 'x' is neglected because partial pressure cannot be negative.

So, the partial pressure for the components at equilibrium are:

$p_{COCl_2}=0.760-0.352=0.408atm\\\\p_{CO}=0.352atm\\\\p_{Cl_2}=0.352atm$

Hence, the partial pressure of the $CO,Cl_2\text{ and }COCl_2$ are 0.352 atm, 0.352 atm and 0.408 atm respectively.

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4 years ago

What must be true about two objects if heat is flowing between them?

Degger [83]

The objects may exchange heat between each other if they are in contact with each other.

The two objects will allow flow of heat between them if they have a difference in temperature from each other.

The heat will flow from higher temperature object to lower temperature object. The will reach a final temperature (common to each other) and then there will be no heat transfer between each other.

6 0

3 years ago

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