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elena-s [515]
3 years ago
11

A 72 g sample contains how many moles of water? (include appropriate sig figs in your answer)

Chemistry
1 answer:
sammy [17]3 years ago
5 0

Answer:

2

Explanation:

yhhh&hhhhhhhhhhhhhhh

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? Match the states of matter to their properties. Drag the items on the left to the correct location on the right. solids Indefi
Fantom [35]

Answer:

Solids: definite shape and definite volume (highest density)

Liquid: indefinite shape and definite volume (glide past each other)

Gas: indefinite shape and indefinite volume (lowest density)

Explanation:

look at the answer

8 0
3 years ago
What determines which element an atom is?
Lana71 [14]
C) number of protons.
4 0
3 years ago
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To understand the relation between the strength of an acid or a base and its pKa and pKb values. The degree to which a weak acid
elena-14-01-66 [18.8K]

Answer:

pKa = 3.675

Explanation:

  • pKa = - Log Ka

∴ <em>C</em> X-281 = 0.079 M

∴ pH = 2.40

let X-281 a weak acid ( HA ):

∴ HA ↔ H+ + A-

⇒ Ka = [H+] * [A-] / [HA]

mass balance:

⇒<em> C</em> HA = 0.079 M = [HA] + [A-]

⇒ [HA] = 0.079 - [A-]

charge balance:

⇒ [H+] = [A-] + [OH-]... [OH-] is negligible; it comes from to water

⇒ [H+] = [A-]

∴ pH = - log [H+] = 2.40

⇒ [H+] = 3.981 E-3 M

replacing in Ka:

⇒ Ka = [H+]² / ( 0.079 - [H+] )

⇒ Ka = ( 3.981 E-3 )² / ( 0.079 - 3.981 E-3 )

⇒ Ka = 2.113 E-4

⇒ pKa = - Log ( 2.113 E-4 )

⇒ pKa = 3.675

8 0
3 years ago
Please help me please it's urgent​
alisha [4.7K]

Answer:

<h2>Paraphrase this! I got this online!</h2>

1.A a Chemical Reaction is a process that involves rearrangement of the molecular or ionic structure of a substance, as opposed to a change in physical form or a nuclear reaction.

1.A Chemical reactions involve breaking chemical bonds between reactant molecules (particles) and forming new bonds between atoms in product particles (molecules)

1A.Chemical bonding, any of the interactions that account for the association of atoms into molecules, ions, crystals, and other stable species that make up the familiar substances of the everyday world.

2a.A gas evolution reaction is a chemical reaction in which one of the end products is a gas such as oxygen or carbon dioxide. Gas evolution reactions may be carried out in a fume chamber when the gases produced are poisonous when inhaled or explosive.

2b.a color change is usually an indicator that a reaction is occurring

2c.Processes involved in changes of state include melting, freezing, sublimation, deposition, condensation, and evaporation

3A.When you increase the pressure, the molecules have less space in which they can move. That greater density of molecules increases the number of collisions

3B.As an object gets hot, its atoms and molecules vibrate. As they vibrate, they release energy in the form of light. ... In chemiluminescence, energy from a chemical reaction excites the electrons of a substance

3C. Catalysis is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst. Catalysts are not consumed in the reaction and remain unchanged after it.

3D.Most chemical reactions involve the breaking and formation of chemical bonds. It takes energy to break a chemical bond but energy is released when chemical bonds are formed. If more energy is released than consumed, then the chemical reaction evolves heat and is said to be exothermic. ... Most reactions are exothermic.

<h2>Paraphrase this! I got this online!</h2><h2>Paraphrase this! I got this online!</h2><h2>Paraphrase this! I got this online!</h2>
3 0
3 years ago
If it takes 2000 years to weather 1 cm of limestone, how long will it take to weather 5 cm of limestone?
Anna71 [15]

Answer:10,0000 years

Explanation:

If it takes 2000 years to weather 1cm of limestone

It will take 5*2000 years to weather 5cm of limestone. This gives us 10000 years.

3 0
3 years ago
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