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3 years ago

6

Which of the following statements about water are true 1) water cover 75% of Earth 2) once water is used it can never be reused

3) only 3% of Earth’s water is fresh 4) water comprises the majority of all plants and animals.

2 answers:

viva [34]3 years ago

8 0

Yea I don’t know so yea

IRINA_888 [86]3 years ago

6 0

Answer:

I guess the 1st one idk

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What is the total pressure in units of kPa in a 7.85 L container that contains 4.45 moles of N2 and 2.45 moles of O2 at a temper

dem82 [27]

Answer:

32.42

Explanation:

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3 years ago

An aqueous solution contains the following ions: cl−, ag , pb2 , no−3, and so2−4. More than one precipitate will form. Identify

klasskru [66]

An aqueous solution contains the following ions Cl⁻, Ag⁺, Pb²⁺, NO₃⁻ & SO₄²⁻ and more than one precipitate will form are AgCl, PbCl₂, PbSO₄ & Ag₂SO₄.

<h3>What is precipitate?</h3>

Precipitate is the insoluble compound which is present at the bottom of any chemical reaction in the solid state.

If in an aqueous solution Cl⁻, Ag⁺, Pb²⁺, NO₃⁻ & SO₄²⁻ ions are present then:

Compounds AgCl, PbCl₂, PbSO₄ & Ag₂SO₄ are not soluble in water as it is present in the form of precipitate.
Pb(NO₃)₂ is fully soluble in water and will not make precipitate.

Hence precipitates are AgCl, PbCl₂, PbSO₄ & Ag₂SO₄.

To know more about precipitates, visit the below link:

brainly.com/question/2437408

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2 years ago

Gifblaar is a small South African shrub and one of the most poisonous plants known because it contains fluoroacetic acid (FCH2CO

PSYCHO15rus [73]

[H_{3}O^{+}] = 0.00770 M

The equilibrium equation representing the dissociation of $FCH_{2}COOH$

$FCH_{2}COOH(aq) + H_{2}O (l) FCH_{2}COO^{-}(aq)+ H_{3}O^{+}(aq)$

Given [H_{3}O^{+}] = 0.00770 M

Let the initial concentration of acid be x and change y

So y = $[H_{3}O^{+}]$ = $[FCH_{2}COO^{-}]$ = 0.00770 M

$pK_{a} = 2.59K_{a} = 10^{-2.59} = 0.00257 M$

$K_{a} = \frac{(0.00770 M)(0.00770 M)}{x - 0.00770}$

$0.00257 = \frac{0.00005929}{x - 0.00770}$

0.00257 x - 0.00001979 = 0.00005929

x = 0.031 M

Therefore, initial concentration of the weak acid is <u>0.031 M</u>

4 0

4 years ago

Magnesium is a metal with two elections in its outermost energy level. When it becomes an ion, what happens to its valence elect

Law Incorporation [45]

Answer:

The answer to your question is Mg loses its valence electrons and acquire a positive charge (Mg⁺²).

Explanation:

Valence electrons are important for an element to attach to another one, metals lose these electrons while nonmetals gain electrons to complete the octet rule.

Magnesium is a metal that loses these electrons so when it becomes an ion Magnesium will have a positive charge Mg⁺².

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3 years ago

Examination of the first few successive ionization energies for a given element usually reveals a large jump between two ionizat

gladu [14]

Answer:

See Explanation

Explanation:

Ionization energy refers to the energy required to remove an electron from an atom. Metals have lower ionization energy than non metals since ionization energy increases across a period.

One thing that we must have in mind is that it takes much more energy to remove an electron from an inner filled shell than it takes to remove an electron from an outermost incompletely filled shell.

Now let us consider the case of magnesium which has two outermost electrons. Between IE2 and IE3 we have now moved to an inner filled shell(IE3 refers to removal of electrons from the inner second shell) and a lot of energy is required to remove an electron from this inner filled shell, hence the jump.

For aluminium having three outermost electrons, there is a jump between IE3 and IE4 because IE4 deals with electron removal from a second inner filled shell and a lot of energy is involved in the process hence the jump.

Hence a jump occurs each time electrons are removed from an inner filled shell.

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3 years ago