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Ne4ueva [31]
2 years ago
9

Which of the following is correct?

Chemistry
2 answers:
Paladinen [302]2 years ago
7 0

Answer:

C when lungs expand they fill with air from the atmosphere

Maru [420]2 years ago
6 0
I think the answer is C.
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A chemist measures the energy change ?H during the following reaction: 2HgO (s) ?2Hg (l) +O2 (g) =?H182.kJ Use the information t
Leni [432]

Answer:

The reaction is endothermic.

Yes, absorbed

3.06x10¹kJ are absorbed

Explanation:

In the reaction:

2HgO(s) → 2Hg(l) + O₂(g) ΔH = 182kJ

As ΔH >0,

<em>The reaction is endothermic</em>

<em />

As the reaction is endothermic, when the reaction occurs,

<em>the heat is absorbed.</em>

<em></em>

Now, based on the equation, when 2 moles of HgO (Molar mass: 216.59g/mol), 182kJ are absorbed.

72.8g are:

72.8g * (1mol / 216.59g) = 0.3361 moles HgO.

that absorb:

0.3361 moles HgO * (182kJ / 2 moles) =

<h3>3.06x10¹kJ are absorbed</h3>
8 0
3 years ago
WILL GIVE BRAINLEST! --
Paladinen [302]

Answer:

d

Explanation:

5 0
3 years ago
Read 2 more answers
A student titrates a 20.00 mL sample of an aqueous borax solution with 1.03 M H2SO4. If 2.07 mL of acid are needed to reach the
RSB [31]

Answer:

The concentration of the borax solution is 0.1066 M

Explanation:

Step 1: Dtaa given

Volume of a sample of aqueous borax solution = 20.00 mL = 0.020 L

Molarity of H2SO4  = 1.03 M

Volume of the H2SO4 = 2.07 mL = 0.00207 L

Step 2: The balanced equation

Na2B4O7*10H2O(borax) + H2SO4 ⇆ Na2SO4 + 4 H3BO3 + 5 H2O

Step 3: Calculate molarity of borax solution

b*Ca*Va = a * Cb*Vb

⇒with B = the coefficient of H2SO4 = 1

⇒with Ca = the concentration of borax = TO BE DETERMINED

⇒with Va = the volume of borax = 0.020 L

⇒with a = the coefficient of borax = 1

⇒with Cb = the concentration of H2SO4 = 1.03 M

⇒with Vb = the volume of H2SO4 = 0.00207 L

Ca*0.020 L = 1.03 M * 0.00207 L

Ca = (1.03 * 0.00207) / 0.020

Ca = 0.1066 M

The concentration of the borax solution is 0.1066 M

6 0
3 years ago
What determines the types of chemical reactions that an atom participates in? A. the number of electrons in the outermost electr
Dafna1 [17]

Answer:

The answer would be A. the number of electrons in the outermost electron shell.

Explanation:

These are called valence electrons which are transferred, shared, and rearranged by creating covalent bonds producing new substances.

Hope this helped! :)

8 0
2 years ago
GO FAST / WILL MARK BRAINLIEST / WILL GIVE THANKS / WILL GIVE 5 STARS
Nikitich [7]
<h2>question  1</h2>

Mg  + 2HCl→ MgCl2 + H2

after balancing the coefficient for H2   is 1

<em><u>explanation </u></em>

since 1  is in front of H2  it is the coefficient for H2


question  2

 the reaction is single replacement

<u><em>explanation</em></u>

  • because  single replacement  occurs when one element  replaces another.  
  • for  the reaction of  Mg + 2HCl→MgCl2 +H2   Chlorine  

<h2>  Question  3</h2>

The   coefficient  of  H2  is 3

<em><u>explanation</u></em>

  • from  the balanced chemical reaction
  • that is  N2 +3H2 →2NH3  the coefficient  in  front of H2  is   3
<h2 /><h2>  question  4</h2>

N2 + 3H2 → 2NH3  is  a  synthesis  reaction

<u><em>explanation; </em></u>

Synthesis reaction  occurs  when two or more  reactants combine  to form a single product.

  • N2  reacted with  H2  to form   NH3 (ammonia) hence  it is  an example of synthesis reaction.

<h2>question 5</h2>
  1. The sign  that shows that a chemical reaction  has occurred  is    color change, change  in temperature  and  formation of a  gas (bubble)

color change  change in temperature, formation  of  precipitate  and formation  of  a gas(bubble)  is always   an indicator of an occurrence of a chemical  change.

<h2>Question 6</h2>

H2S is not  a strong acid

<u><em>explanation</em></u>

  • strong acid undergo a complete electrolysis  when dissociate in water  for example  HNO3  
  • weak acid  undergo  a partial electrolysis  when dissociate in water   for example  H2S

<h2>question 7</h2>

feels slippery  is not  a property of an acid

<u><em>explanation</em></u>

  • feel  slippery is an example of a  base
  •  The properties of an acid are
  1. sour taste
  2. changes the color of an indicator
  3. usually react with metal among  others
<h2>  Question   8</h2>

detergent with a PH of about  10  is a  <u><em>basic</em></u>

<em><u>explanation</u></em>

  • Base has    a Ph  which range  from 7.1 to  14
  • since  the detergent  has a PH of 10 is a basic
<h2>Question 9</h2>

The balanced chemical equation  for the synthesis  of NaBr is

2Na  + Br2 →2 NaBr

<u><em>explanation</em></u>

 This is because the  equation obey the law of mas  conversation

   for  example it has  2 atoms of  Na   in both reactant and product side

<h2>Question 10</h2>

 reacts with metals  is not  a common  property of  a base

 <u><em>Explanation</em></u>

  • base has  
  1. bitter taste,
  2. feels slippery
  3. turn red litmus paper blue  among others
<h2>  question  11</h2>

Hydrochloric acid have  a PH   in  0-6 range

<u><em>explanation</em></u>

  • HCl  is a strong  acid  
  •  acid has a PH  which are below PH  of 7  hence HCl  has a PH which range from 0-6

<h2>Question 12</h2>

A brand  shampoo  which has a PH between  5 -6 is  a weak  acid

  •    generally acid  has  a PH below   7
  • weak  acid  has a PH of between  5 -6  therefore  brand  shampoo  is a weak  acid
<h2>question 13</h2>

The PH  that indicate  a  solution  of a  base is a PH of 12

 <em><u>Explanation</u></em>

  • base  has a PH  which range between 7-14, hence  a  PH of 12   indicate that it is a  Base
7 0
3 years ago
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