**Answer:**

<h2>3920 Joules</h2>

**Explanation:**

The potential energy of a body can be found by using the formula

PE = mgh

where

m is the mass

h is the height

g is the acceleration due to gravity which is 9.8 m/s²

From the question we have

PE = 40 × 9.8 × 10

We have the final answer as

<h3>3920 J</h3>

Hope this helps you

<span>The best choice is hypochlorous acid nitrous acid (HNO2) because it has the nearest value of pK to the desired pH.

pKa of </span>nitrous acid<span> is 3.34

If we know pKa and pH values, we can calculate the required ratio of conjugate base (NO2⁻) to acid (HNO2) from the following equation:

pH=pKa + log(conc. of base)/( conc. of acid)

</span><span>3.19=3.34 + log c(NO2⁻)/c(HNO2)

</span><span>3.19 - 3.34 = log c(NO2⁻)/c(HNO2)

-0.15 = log c(NO2⁻)/c(HNO2)

c(NO2⁻)/c(HNO2) = 10⁰¹⁵ = 1.41

</span>

The grams of aluminium extracted from 5000g of alumina is **2647 grams**

<h3>Chemical formula of alumina:</h3>

Let's calculate the molecular mass of **Al₂O₃**

**Al₂O₃ = **27 × 2 + 16 × 3 **=** 54 + 48 =** 102 g/mol**

**Therefore,**

102 g of Al₂O₃ = 54 g of aluminium

**5000g of Al₂O₃** = ?

**mass of aluminium produced = 5000 × 54 / 102 **

mass of aluminium produced = 270000 / 102

mass of aluminium produced = 2647.05882353

**mass of aluminium produced = 2647 grams**

learn more on **mass** here: brainly.com/question/14627327

Answer:

1) pentane is of higher Molecular mass than propane hence heavier member

2) due to intermolecular hydrogen bonding methanol is liquid having lower molecular weight

3) I) in methanol C = sp3

ii) in methanoic acid C= sp2

5)I) i) The two carbon-oxygen bonds in the methanoate anion, HCO2-, have the same length due to resonance stabilization of the C-O bond

Explanation:

See attachment for question 4