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
irinina [24]
3 years ago
12

Petunia needs 66.48 grams of potassium hydroxide (KOH) to run a reaction in class. How many moles of potassium hydroxide does sh

e need? Please round your answer to two digits after the decimal point, and remember to include correct, complete units (including substance formula).
Chemistry
1 answer:
Kaylis [27]3 years ago
4 0

Answer:

She needs 1.19 moles of potassium hydroxide.

Explanation:

Being the molar mass of the elements:

  • K= 39 g/mole
  • O= 16 g/mole
  • H= 1 g/mole

then the molar mass of potassium hydroxide is:

KOH= 39 g/mole + 16 g/mole + 1 g/mole= 56 g/mole

Being the mass of one mole of a substance, which can be an element or a compound, you can apply the following rule of three: if 56 g of KOH are present in 1 mole, 66.48 g of KOH in how many moles of the compound are they?

moles of KOH=\frac{66.48 grams*1 mole}{56 grams}

moles of KOH= 1.19

<u><em> She needs 1.19 moles of potassium hydroxide.</em></u>

You might be interested in
A piece of unknown metal with mass 68.6 g is heated to an initial temperature of 100 °C and dropped into 42 g of water (with an
professor190 [17]

Answer:

1.717 J/g °C  ( third option)

Explanation:

A piece of the unknown metal dropped into water this means that Q of metal is equal to Q of the water. We write this equality as follows:

<u>Step 1: writing the formulas:</u>

Q = mc∆T

⇒ -Q(metal) = Q(water)   Because :Metal dropped into water this means that Q of metal is equal to Q of the water.

<em>We can write the formula different :</em>

Mass of metal * (cmetal)(ΔT) = Mass of water *(cwater) (ΔT)

⇒ Here c is the specific heat and depends on material and phase

<em>For this case :</em>

mass of the metal  = 68.6g

mass of the water = 42g

Specific heat of the metal = TO BE DETERMINED

Specific heat of the water = 4.184J/g °C

Initial temperature of the metal = 100 °C  ⇒ Change of temperature: 52.1 - 100

Initial temperature of the water = 20°C  ⇒ Change of temperature:  52.1 - 20

<u />

<u>Step 2: Calculating specific heat of the metal</u>

-(Mass of metal) * (cmetal)*(ΔT)) = (Mass of water) *(cwater)*(ΔT)

-68.6g (cmetal)(52.1 - 100) = 42g (4.184j/g °C) (52.1 - 20)

-68.6g *cmetal * (-47.9) = 42g (4.184j/g °C) *(32.1)

3285.94 * cmetal = 5640.87

cmetal = 5640.87 / 3285.94 = 1,71667 J/g °C

cMetal = 1.717 J/g °C

4 0
2 years ago
Personal eyeglasses provide as much protection as Group of answer choices splash proof chemical goggles a face shield safety gla
MArishka [77]

Answer:

none of the above

Explanation:

6 0
3 years ago
If 0.500 mol of each of the following solutes is dissolved in 2.0 L of water, which will cause the greatest increase in the boil
serious [3.7K]

Answer is: D. Na2SO4.

b(solution) = 0.500 mol ÷ 2.0 L.

b(solution) = 0.250 mol/L.

b(solution) = 0.250 m; molality of the solutions.

ΔT = Kf · b(solution) · i.

Kf - the freezing point depression constant.

i - Van 't Hoff factor.

Dissociation of sodium sulfate in water: Na₂SO₄(aq) → 2Na⁺(aq) + SO₄²⁻(aq).

Sodium sulfate dissociates on sodium cations and sulfate anion, sodium sulfate has approximately i = 3.

Sodium chloride (NaCl) and potassium iodide (KI) have Van 't Hoff factor approximately i = 2.

Carbon dioxide (CO₂) has covalent bonds (i = 1, do not dissociate on ions).

Because molality and the freezing point depression constant are constant, greatest freezing point lowering is solution with highest Van 't Hoff factor.

8 0
3 years ago
Read 2 more answers
How many dots should be shown in the Lewis dot diagram of oxygen? (1 point)
deff fn [24]

Answer: the answer is number 3 which is 6

8 0
3 years ago
Scientist can use trees to look at climates of the past. How? What information can they gather and how do they gather it? Explai
andrezito [222]

Explanation:

Scientist use trees a whole lot to look at climate of the past by examining tree rings.

These are layers of cambium in each successive years formed. They have an annual growth pattern and are known as tree rings.

Tree rings can be used to decipher the age of a tree.

  • These three rings can be used to interpret climatic patterns.
  • During a wet climate, the tree rings are more robust and bigger.
  • In a dry climate, the rings are thinner.
  • These alternating patterns can be used to decipher the climatic signatures in a tree.
  • Sometimes, it is possible to evaluate some certain isotopes that are useful in climatic studies.

learn more:

Climate change brainly.com/question/7824762

#learnwithBrainly

6 0
2 years ago
Other questions:
  • What is the maximum mass of aluminum chloride that can be formed when reacting 18.0 g of aluminum with 23.0 g of chlorine?
    7·2 answers
  • What is dermal tissue
    14·2 answers
  • A cube has a mass of 100 grams and it’s density to be 1 g/cm cubed . The volume of the cube must be ?
    12·1 answer
  • What happens if a solid changes the state of substance to liquid?
    14·2 answers
  • Consider the balanced equation below.
    12·2 answers
  • If you have 9900 g of donuts, how many donuts do you have if each donut has a mass of 150 g?
    12·1 answer
  • Please anyone help please I will pray for you
    15·1 answer
  • H e l p SOMEONEEEEEEEEEEE ANYONEEEEEE
    5·1 answer
  • Determine the relative formula mass of dihydrogen monoxide using the periodic table below.
    11·1 answer
  • At what point on the roller coaster do the riders have the greatest amount of potential energy?
    13·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!