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1 year ago

4. Which statement correctly explains why hydrogen fluoride dissolves in water?

1 answer:

3 0

The ANSWER is D

salt In water because it is a simple ion pair Na+1 and Cl-1

Hydrogen Fluoride is similar: H+1 and F-1 and since it is a polar ion pair too it dissolves in water

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The stability of an isotope is based on its

sattari [20]

Option 4. ratio of electrons to protons

Isotope that has atomic number of 82 is stable. An element that has an atomic number ∠82 more stable except Tc and Pm. Also there is the concept that isotopes consisting a combination of even-even,even-odd,odd-even, and odd-odd are all stable. Many isotopes with no magic numbers of nucleons are stable

7 0

2 years ago

Stearic acid (C18H36O2) is a fatty acid, a molecule with a long hydrocarbon chain and an organic acid group (COOH) at the end. I

Paha777 [63]

Answer:

There is 9671 Kj of heat released

Explanation:

Step 1: The balanced equation:

C18H36O2(s) + 26O2(g) --> 18CO2(g)+18H2O(g)

This means for 1 mole of C18H36O2 consumed there is 26 moles of O2 needed to produce 18 moles of CO2 and 18 moles of H2O.

Step 2: Calculate the heat of combustion

ΔH (combustion) = [18*(ΔHf of CO2) + 18*(ΔHf of H2O)] - [1*(ΔHf of C18H36O2) + 26*(ΔHf of O2)]

ΔH (combustion) = [18*(-394 kJ/mol) + 18*(-242 kJ/mol)] - [1*(-948 kJ/mol) + 26*(0 kJ/mol)]

ΔH (combustion) = [(-7092 kJ/mol) + (-4356 kJ/mol)] - (-948 kJ/mol)

= -10500 kJ/mol

ΔH (combustion) = heat released / number of moles of stearic acid

Step 3: Calculate moles of stearic acid

moles of stearic acid = mass / Molar mass of stearic acid

moles of stearic acid = 262g / 284.48 g/mole = 0.921 moles

Step 4: Calculate moles of oxygen

moles of O2 = 914.5 / 32g/mole

moles of O2 = 28.578125 moles

Stearic acid is the limiting reactant: it will completely react

There will react 26*0.921 mole = 23.946 mole of O2

This means there will remain 4.63 moles of O2

Step 5: Calculate heat released

q = (ΔH combustion) * (moles of stearic acid) = (-10500 kJ/mol) * (0.921 moles) = 9671 Kj

There is 9671 Kj of heat released

6 0

2 years ago

How many moles of sodium hydroxide are there in 1.0mL of 2.0M NaOH

kvasek [131]

To find the moles, you can use the following formula

moles= Molarity x Liters

Molarity= 2.0 M
Liters= 0.0010 Liters ---------------->>>>>>>>>> 1.0 mL= 0.0010 Liters

moles= 2.0 M x 0.0010 Liters= 0.0020 moles

4 0

2 years ago

3. Hydrogen reacts with nitrogen to produce ammonia according to the equation:

lys-0071 [83]

Mass of ammonia produced : 121.38 g

<h3>Further explanation</h3>

Given

Reaction

3H₂(g) + N₂(g) ⇒ 2NH₃(g)

100g of N₂

Required

Ammonia produced

Solution

mol of N₂ :

$\tt mol=\dfrac{mass}{MW}\\\\mol=\dfrac{100}{28}\\\\mol=3.57$

From the equation, mol ratio of N₂ and NH₃ = 1 : 2, so mol NH₃ :

$\tt \dfrac{2}{1}\times 3.57=7.14~moles$

mass of NH₃(MW=17 g/mol) :

$\tt mass=mol\times MW\\\\mass=7.14\times 17\\\\mass=121.38~g$

8 0

2 years ago

4. Imagine you have a radioactive sample containing both Virtualium and decayed atoms of Virtualium. After analysis, you find it

Romashka [77]

My sample would be 4000 years old because on my graph, I had about 9 Virtualium left at trial 4 so I am guessing that it would be 4000 years old.

7 0

2 years ago