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4 years ago

Why do we use gold and silver to make jewellery?

Chemistry

1 answer:

Firdavs [7]4 years ago

3 0

Explanation:

Gold and Silver is used for making ornaments because of their malleability and durability. Gold is the most malleable metal. For e.g, a small piece is gold nearly 3.5gm can be made a kilometer thin wire. Gold and and silver are also very lusturous and looks very much lookrative.

Hope this helps

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C12H22011+1202-->12CO2+11H20

kogti [31]

Answer:

0.185moles

Explanation:

Given parameters:

Volume of O₂ = 49.8L

Unknown:

Number of moles of sucrose required = ?

Solution:

We can assume that the reaction takes place at standard temperature and pressure.

From this, we can find the number of moles of oxygen that reacted and extrapolate to that of sucrose.

Chemical equation;

C₁₂H₂₂0₁₁ + 120₂ → 12CO₂ + 11H₂0

Number moles = $\frac{volume of gas}{22.4}$ at STP

Number of moles of oxygen gas = $\frac{49.8}{22.4}$ = 2.22moles

12 moles of oxygen gas combines with 1 mole of sucrose

2.22 moles of oxygen gas will combine with $\frac{2.22}{12}$ = 0.185moles

4 0

4 years ago

Does anyone know how to do this? the solubility of barium carbonate, BaCO3, is 0.0100 g/L. Its molar mass is 197.3 g/mol. What i

g100num [7]

It's simple, just follow my steps.

1º - in 1 L we have $0.0100~g$ of $BaCO_3$

2º - let's find the number of moles.

$\eta=\frac{m}{MM}$

$\eta=\frac{0.0100}{197.3}$

$\boxed{\boxed{\eta=5.07\times10^{-5}~mol}}$

3º - The concentration will be

$C=5.07\times10^{-5}~mol/L$

But we have this reaction

$BaCO_3\rightleftharpoons Ba^{2+}+CO_3^{2-}$

This concentration will be the concentration of $Ba^{2+}~~and~~CO_3^{2-}$

$K_{sp}=\frac{[Ba^{2+}][CO_3^{2-}]}{[BaCO_3]}$

considering $[BaCO_3]=1~mol/L$

$K_{sp}=[Ba^{2+}][CO_3^{2-}]$

and

$[Ba^{2+}]=[CO_3^{2-}]=5.07\times10^{-5}~mol/L$

We can replace it

$K_{sp}=(5.07\times10^{-5})*(5.07\times10^{-5})$

$K_{sp}\approx25.70\times10^{-10}$

Therefore the $K_{sp}$ is:

$\boxed{\boxed{\boxed{K_{sp}\approx2.57\times10^{-11}}}}$

4 0

4 years ago

Read 2 more answers

Lead has a density of 11.3 g/cm3. if you have 1.0 kg of lead, what is the volume in cubic centimeters (cm3)? remember to select

Novosadov [1.4K]

In this case, you are given the density( 11.3g/cm3) and the weight (1kg) of the lead. You are asked to find the volume of the lead.
To find volume you need to divide the weight with the density. It would be:
volume= weight/density
volume = 1kg x (1000 gram/kg) / (11.3g/cm3)= 88.495 cm3

4 0

4 years ago

Solid sodium metal reacts violently with water, producing heat, hydrogen gas, and sodium hydroxide. How many molecules of hydrog

asambeis [7]

Answer:

4.6 × 10²³ molecules:

Step-by-step solution

You will need a balanced equation with masses, moles, and molar masses, so let's gather the information in one place:

M_r: 22.99

2Na + 2H₂O ⟶ 2NaOH + H₂

m/g: 35

1. Calculate the moles of Na

Moles of Na = 35 g Na × (1 mol Na/22.99 g Na)

Moles of Na = 1.52 mol Na

2. Calculate the moles of H₂

Moles of H₂ = 1.52 mol Na × (1 mol H₂/2 mol Na)

Moles of H₂= 0.761 mol H₂

3. Calculate the molecules of H₂

6.022 × 10²³ molecules H₂ = 1 mol H₂

Molecules of H₂ = 0.761 × (6.022 × 10²³ /1)

Molecules of H₂ = 4.6 × 10²³ molecules H₂

The reaction forms 4.6 × 10²³ molecules of H₂.

5 0

3 years ago

What is one thing that wind, solar, and hydropower all have in common?

vampirchik [111]

Answer:

they are all renewable resources!

Explanation:

Hope this helps! ;-)

7 0

3 years ago

Read 2 more answers