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3 years ago

Help Asap plz Thx giving lots of points!!!

Chemistry

1 answer:

3241004551 [841]3 years ago

3 0

29. B) A population changes in response to a change in the environment.

Evolution is the process by which new species of organisms develop from earlier forms. Most often, in response to a change in a species environment. It's the frequent change of the alleles in a population.

30. A) Describes the relationship between an organism and its environment

Darwin made this theory of evolution by natural selection as an explanation for adaptation. Darwin defined natural selection as the

"principle by which each slight variation, if useful, is preserved."

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The levels of organization within an organism are atom,

OleMash [197]

Answer:

The answer is: Molecule and Organ system.

4 0

2 years ago

Read 2 more answers

What are you suppose to do for number 8?

Nadya [2.5K]

Answer:

See the images below

Step-by-step explanation:

To draw a dot diagram of an atom, you locate the element in the Periodic Table and figure out how many valence electrons it has. Then you distribute the electrons as dots around the atom,

a. Silicon.

Si is in Group 14, so it has four valence electrons.

b. Xenon

Xenon is in Group 18, so it has eight valence electrons. We group them as four pairs around the xenon atom.

c. Calcium

Calcium is in Group 2, so it has two valence electrons. They are in a single subshell, so we write them as a pair on the calcium atom.

d. Water

Oxygen is in Group 16, so it has six valence electrons. The hydrogen atoms each contribute one electron, so there are eight valence electrons.

Chemists often use a dash to represent a pair of electrons in a bond.

3 0

3 years ago

Earths rotation takes about __________, whereas its revolution takes about _______.

Sergio [31]

A.) a rotation is the earth "rotating" on its axis while a revolution is the earth "revolving" around the sun so 1 rotation is from sun rise to sun rise while one revolution is from January 1st to the next January 1st

8 0

3 years ago

An important step in science is supporting a theory or idea without data. The questions we ask determine the type of data we col

san4es73 [151]

Answer:

What will happen to Uk if you double the mass?

Explanation:

Uk = 0.5 * m * v²

You see that both m and v are variable, which means that both m and v can be any number. Regardless of the numbers you put in for m or v, the formula to calculate the kinetic energy (Uk) remains valid.

You could ask

1. What will happen to Uk if you double the mass?

2. What will happen to Uk if you double the velocity?

please see and understand(!) that the relationship between Uk an v² is indeed the velocity squared....

EXTRA

Uk = 0.5 * m * (v)²

Suppose the m = 3kg and velocity = 5 m/s

What is the Uk?

Well if you know the formula you can use your calculator to find out:

Uk = 0.5 * m * (v)²

Uk = 0.5 * 3 * (5)²

Uk = 0.5 * 3 * 25

Uk = 37.5 kgm/s²

Again you ask what will happen to Uk if you double the velocity?

At first it was 5 m/s and now it doubles, which means it now has that value *2

The new velocity is 5 *2 = 10 m/s

Uk = 0.5 * m * (v)²

Uk = 0.5 * 3 * (10)²

Uk = 0.5 * 3 * 100

Uk = 150 kgm/s²

150 = 4 * 37.5

So now you see that if you double your velocity, the Uk will be 2² = 4 times as big !

3 0

3 years ago

In addition to mass balance, oxidation-reduction reactions must be balanced such that the number of electrons lost in the oxidat

Fiesta28 [93]

Answer:

Part A: (1, 1, 4, 1, 1, 1)

Part B: (2, 6, 4, 2, 3, 8)

Explanation:

Redox reactions can be balanced using the half-reaction method. It has the following steps:

We write both half-reactions (reduction and oxidation)
We balance the masses using H⁺ and H₂O in acidic media or OH⁻ and H₂O in basic media.
We add electrons to balance electrically the half-reaction
We multiply the half-reaction by numbers to make sure the number of electrons gained and lost are the same.
We add both half-reactions and take the numbers to the general equation.

Acidic solution

SO₄²⁻(aq) + Sn²⁺(aq) + X ⇄ H₂SO₃(aq) + Sn⁴⁺(aq) + Y

Reduction: SO₄²⁻ ⇒ SO₃²⁻

Oxidation: Sn²⁺ ⇒ Sn⁴⁺

2 H⁺ + SO₄²⁻ ⇒ SO₃²⁻ + H₂O

Sn²⁺ ⇒ Sn⁴⁺

2 H⁺ + SO₄²⁻ + 2 e⁻ ⇒ SO₃²⁻ + H₂O

Sn²⁺ ⇒ Sn⁴⁺ + 2 e⁻

1 x [2 H⁺ + SO₄²⁻ + 2 e⁻ ⇒ SO₃²⁻ + H₂O]

1 x [Sn²⁺ ⇒ Sn⁴⁺ + 2 e⁻]

2 H⁺ + SO₄²⁻ + 2 e⁻ + Sn²⁺ ⇄ SO₃²⁻ + H₂O + Sn⁴⁺ + 2 e⁻

2 H⁺ + SO₄²⁻ + Sn²⁺ ⇄ SO₃²⁻ + H₂O + Sn⁴⁺

Taking this to the general equation:

SO₄²⁻(aq) + Sn²⁺(aq) + 2 H⁺(aq) ⇄ H₂SO₃(aq) + Sn⁴⁺(aq) + H₂O(l)

Since H⁺ are spectator ions, they are not balanced automatically through this method and we have to balance them manually. In this case, we need to add 2 more H⁺ to the left.

SO₄²⁻(aq) + Sn²⁺(aq) + 4 H⁺(aq) ⇄ H₂SO₃(aq) + Sn⁴⁺(aq) + H₂O(l)

Basic solution

MnO₄⁻(aq) + F⁻(aq) + X ⇄ MnO₂(s) + F₂(aq) + Y

Reduction: MnO₄⁻ ⇒ MnO₂

Oxidation: F⁻ ⇒ F₂

2 H₂O + MnO₄⁻ ⇒ MnO₂ + 4 OH⁻

2 F⁻ ⇒ F₂

2 H₂O + MnO₄⁻ + 3 e⁻ ⇒ MnO₂ + 4 OH⁻

2 F⁻ ⇒ F₂ + 2 e⁻

2 × (2 H₂O + MnO₄⁻ + 3 e⁻ ⇒ MnO₂ + 4 OH⁻)

3 × (2 F⁻ ⇒ F₂ + 2 e⁻)

4 H₂O + 2 MnO₄⁻ + 6 e⁻ + 6 F⁻ ⇄ 2 MnO₂ + 8 OH⁻ + 3 F₂ + 6 e⁻

4 H₂O + 2 MnO₄⁻ + 6 F⁻ ⇄ 2 MnO₂ + 8 OH⁻ + 3 F₂

Taking this to the general equation:

2 MnO₄⁻(aq) + 6 F⁻(aq) + 4 H₂O ⇄ 2 MnO₂(s) + 3 F₂(aq) + 8 OH⁻

This equation is balanced.

6 0

3 years ago