1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
kkurt [141]
3 years ago
13

Help please 12 point

Chemistry
1 answer:
Artyom0805 [142]3 years ago
7 0
An exothermic reaction is a chemical reaction that releases energy by light or heat. It is the opposite of an endothermic reaction. im sorry i only could do one! but hope this helped!
You might be interested in
Item 3
svetoff [14.1K]

Answer:

Semiconductors are poor conductors at low temperatures, but their resistance decreases with increasing temperature.

Explanation:

A semiconductor can be defined as a crystalline solid substance that has its conductivity lying between that of a metal and an insulator, due to the effects of temperature or an addition of an impurity. Semiconductors are classified into two main categories;

1. Extrinsic semiconductor.

2. Intrinsic semiconductor.

The statement which best describes the electrical conductivity of metals and semiconductors is that semiconductors are poor conductors at low temperatures, but their resistance decreases with increasing temperature.

This ultimately implies that, semiconductors are typically an insulator (poor conductor) at low temperatures and a good conductor at high temperatures.

Additionally, conduction involves the transfer of electric charge or thermal energy due to the movement of particles. When the conduction relates to electric charge, it is known as electrical conduction while when it relates to thermal energy, it is known as heat conduction.

6 0
3 years ago
A 50.0-mL volume of 0.15 M HBr is titrated with 0.25 M KOH. Calculate the pH after the addition of 13.0 mL of KOH. Express your
Mazyrski [523]

Answer:

pH= 1.17

Explanation:

The neutralization reaction between HBr (acid) and KOH (base) is given by the following equation:

HBr(aq) + KOH(aq) → KBr(aq) + H₂O(l)

According to this equation, 1 mol of HBr reacts with 1 mol of KOH. Then, the moles can be expressed as the product between the molarity of the acid/base solution (M) and the volume in liters (V). So, we calculate the moles of acid and base:

<u>Acid</u>:

M(HBr) = 0.15 M = 0.15 mol/L

V(HBr) = 50.0 mL x 1 L/1000 mL = 0.05 L

moles of HBr = M(HBr) x V(HBr) = 0.15 mol/L x 0.05 L = 7.5 x 10⁻³ moles HBr

<u>Base</u>:

M(KOH) = 0.25 M = 0.25 mol/L

V(HBr) = 13.0 mL x 1 L/1000 mL = 0.013 L

moles of HBr = M(HBr) x V(HBr) = 0.25 mol/L x 0.013 L = 3.25 x 10⁻³ moles KOH

Now, we have: 7.5 x 10⁻³ moles HBr > 3.25 x 10⁻³ moles KOH

HBr is a strong acid and KOH is a strong base, so they are completely dissociated in water: the acid produces H⁺ ions and the base produces OH⁻ ions. So, the difference between the moles of HBr and the moles of KOH is equal to the moles of remaining H⁺ ions after neutralization:

moles of H⁺ = 7.5 x 10⁻³ moles HBr - 3.25 x 10⁻³ moles KOH = 4.25 x 10⁻³ moles H⁺

From the definition of pH:

pH = -log [H⁺]

The concentration of H⁺ ions is calculated from the moles of H⁺ divided into the total volume:

total volume = V(HBr) + V(KOH) = 0.05 L + 0.013 L = 0.063 L

[H⁺] = (moles of H⁺)/(total volume) = 4.25 x 10⁻³ moles/0.063 L = 0.067 M

Finally, we calculate the pH after neutralization:

pH = -log [H⁺] = -log (0.067) = 1.17

3 0
3 years ago
How many neutrons are present in an atom of
Tamiku [17]
There’s going to be 8 neutrons presented
4 0
3 years ago
How many grams are 0.5 moles of NaCl???
elena-14-01-66 [18.8K]

Answer:Respuesta. El peso molecular de NaCl es 58gr que equivale a 1 mol. g? hay 0,5mol queda 29gr

Explanation:

3 0
3 years ago
PLEASE HELP ME NOW I NEED HELP What will happen if a single crystal is introduced into a super-saturated solution? a. The crysta
Klio2033 [76]

Answer:

c

It excess out the crystal

4 0
3 years ago
Other questions:
  • Whats the volume of 0.522 moles of carbine dioxide
    8·1 answer
  • What are indicators of a chemical reaction would you want in a reaction used in airbag?
    10·2 answers
  • HNO2+ F- &lt;—&gt; HF + NO2 in the reverse reaction HF is a/an
    11·1 answer
  • Which compound will have the larger rf value on a si02 tlc plate using 10 % ethyl acetate/ hexane as eluent: 3-decanone or 3-dec
    14·1 answer
  • Which of the following is NOT correct about elements?
    14·2 answers
  • Where do the words go? please help me ASAP!!!​
    14·2 answers
  • A chemical property of oxygen is that it ____
    6·2 answers
  • Hcl and 1-isopropylcyclohexane formation
    13·2 answers
  • How much 2 M HBr is needed to neutralize 380 mL of 0.1 M NH4OH?
    14·1 answer
  • How many moles of NaCl are required to make 2.85L of a 0.10M solution?Use the correct abbreviation for the UNITS and watch the S
    10·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!