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4 years ago

For each item, choose whether the change is a physical change or a chemical change.

Chemistry

1 answer:

maw [93]4 years ago

8 0

Answer:

Explanation:

Exploding Firecracker - Chemical Change

Mowing Grass - Physical Change

Breaking a Window - Physical Change

Spreading butter on toast - Physical Change

burning wood in a fireplace - Chemical Change

acid rain corroding gravestones: Chemical Change

In a physical change, the chemical composition is not altered, easily reversible and no new substance is formed.

In a chemical change, the chemical composition of the substance is altered. Not reversible and a new substance is always formed at the end of the reaction.

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Chemistry!! Please help

m_a_m_a [10]

Answer:

5.3 × 10⁻¹⁷ mol·L⁻¹

Explanation:

Let s = the molar solubility.

Cu₂S(s) ⇌ 2Cu⁺(aq) + S²⁻(aq); K_{sp} = 6.1 × 10⁻⁴⁹

E/mol·L⁻¹: 2s s

K_{sp} =[Cu⁺]²[S²⁻] = (2s)²×s = 4s^3 = 6.1 × 10⁻⁴⁹

$s^{3}= \frac{6.1 \times 10^{-49}}{4} = 1.52 \times 10^{-49}$

$s = \sqrt[3]{1.52 \times 10^{-49}} \text{ mol/L} = 5.3 \times 10^{-17} \text{ mol/L}$

6 0

4 years ago

If the number of atoms of each element on the reactant side of an equation is equal to the number of atoms of each element on th

cricket20 [7]

C. Is your answer hope you have a wonderful day

6 0

3 years ago

Ferric chloride is being applied for coagulation at a 15.0 MGD surface water treatment plant, at a rate of 195 pounds per day. A

s344n2d4d5 [400]

5850 pounds of this chemical will be used in a 30-day month.

195 pounds per day.

So, 30 days = 195 * 30

= 5850 pounds

Iron(III) chloride is the inorganic compound with the components FeCl 3. additionally known as ferric chloride, it is a commonplace compound of iron inside the +3 oxidation country. The anhydrous compound is crystalline and stable with a melting point of 307.6 °C.

The primary use of ferric chloride is to dispose of impurities in water and for wastewater treatment. Ferric chloride is likewise one of the few water remedy chemical compounds that can sequester odors.

Reasonably poisonous with the aid of ingestion but a strong irritant to the skin and eyes. it's far moderately corrosive and skin touch should be avoided and avoid skin and eye contact.

Learn more about ferric chloride here brainly.com/question/13617260

#SPJ4

6 0

2 years ago

Which of these trends increase as you go from top to bottom on the Periodic Table? Select all that apply.

Oduvanchick [21]

b. atomic radius

as it goes increases when it goes down the periodic table, it decreases when going left to right. all the others decrease while going down the table.

if it helps you to remember, everything here besides atomic radius has an e in it. and if you make a connection with it to electrons, they are negative, which means they would decrease going down the table. so e=decrease while going down

thats what helped me remember it, so i hope this technique could help you too.

4 0

3 years ago

Which of the following is the valence elec- tronic structure for a halogen? 1. n s1 2. n s2 3. n s2 n d10 4. n s2 n p5 5. n s2 n

Arturiano [62]

Answer: option 4. ns² np⁵

Explanation:

The valence electronic structure of the compounds is the distribution of the valence electrons, i.e. the outermost electrons of the atoms.

The distribution of the electrons in the atomic orbitals is named electron configuration.

Each element has a proper electron configuration which is determined according to a series of rules: lowest orbital energy, Pauli's exclusion principle and Hund's rule.

The valence electronic structure of the atoms is related with the period (column of the periodic table) to which the element belongs.

Each period has a characteristic valence structure (number and location of the outermost electrons). It is this structure what conferes the elements of a same period (column in the periodic table) their similar chemical properties.

This table summarizes the valence eletronic structure of the representative elements:

Period (column) name number of valence eletrons Structure

1 Alkali metals 1 ns¹

2 Alkaline earth metals 2 ns²

13 3 ns² np¹

14 4 ns² np²

15 Pnictogens 5 ns² np³

16 Chalcogens 6 ns² np⁴

17 Halogens 7 ns² np⁵

18 Noble gases 8 ns² np⁶

There you can see that the halogens belong to the period 17, have 7 valence electrons, and their valence electrons are have the structure ns² np⁵.

This is the specific valence electronic structure for the first five halogens:

Halogen atomic number row (n) period valence electronic structure

Fluor 9 2 15 2s² 2p⁵

Chlorine 17 3 15 3s² 3p⁵

Bromine 35 4 15 4s² 4p⁵

Iodine 53 5 15 5s² 5p⁵

Astatine 85 6 15 6s² 6p⁵

There you see the common structre ns² np⁵.

8 0

4 years ago