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3 years ago

Gold has density of 19.3 g/cm3; how many grams of gold are in a 16.0 cm3 gold bar?

1 answer:

6 0

To determine the mass of gold, we simply multiply the density and volume. Density is a value for mass, such as kg, divided by a value for volume, such as m3. Density is a physical property of a substance that represents the mass of that substance per unit volume. We do as follows:

mass = density x volume
mass = 19.3 g/cm^3 ( 16.0 cm^3 )
mass = 308.8 g

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2. The empirical formula of a molecule is CH2O. In an experiment, the molar mass of the molecule was determined to be 360.3 g/mo

Vanyuwa [196]

Answer:

The answer to your question is:

2.- C₁₂ H₂₄ O₁₂

Explanation:

2.-

Data

CH2O

molar mass = 360.3 g/mol

Molar mass of CH2O = 12 + 2 + 16 = 30g

Divide molar mass given by molar mass obtain

x = 360.3/30

x = 12

Finally

C₁₂ H₂₄ O₁₂

Molar mass = (12 x 12) + (24 x 1) + (16 x 12) = 144 + 24 + 192 = 360 g

3.- First we need to write the complete equation of the reaction and balanced it.

Then, we need to convert the mass given to moles of each compound.

After that, we need used rule of three calculate the amount of products based on the moles of reactants given.

Finally, convert the moles to grams.

4.-

a.- It is a relation between the mass of product obtain in an experiment and the mass of a product obtain theoretically times 100.

b.-

35 g of Mg reacted with excess O2

percent yield = 90%

Actual yield = ?

Formula

Percent yield = (actual yield/theoretical yield) x 100

Equation

2Mg + O2 ⇒ 2MgO

48.62 g of Mg ----------------- 80.62 g of MgO

35g ------------------ x

x = 58 g of MgO (Theoretical yield)

Theoretical yield = 58 g of MgO

Actual yield = percent yield x theoretical yield / 100

= 90 x 58 / 100

= 52. 23 g

5 0

3 years ago

Determine the percentage of carbon and hydrogen in ethane C2H6 if the molecular weight is 30.

Naddika [18.5K]

Answer:

Percentage of carbon:

${ \tt{ = \frac{24}{30} \times 100\%}} \\ = 80\%$

Percentage of hydrogen:

${ \tt{ = \frac{6}{30} \times 100\%} } \\ = 20\%$

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3 years ago

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lianna [129]

Nuclear energy comes from splitting of Barium atom to form Krypton atom

5 0

3 years ago

Look at the image below. What is the ratio of the formula shown? *

aleksklad [387]

It’s 1:1 b3cuae that’s the one u can

6 0

2 years ago

Read 2 more answers

Calculate the pH of the following simple solutions:

IceJOKER [234]

Answer :

(1) pH = 1.27

(2) pH = 13.35

(3) The given solution is not a buffer.

Explanation :

(1) 53.1 mM HCl

Concentration of HCl = $53.1mM=53.1\times 10^{-3}M$

As HCl is a strong acid. So, it dissociates completely to give hydrogen ion and chloride ion.

So, Concentration of hydrogen ion= $53.1\times 10^{-3}M$

pH : It is defined as the negative logarithm of hydrogen ion concentration.

$pH=-\log [H^+]$

$pH=-\log (53.1\times 10^{-3})$

$pH=1.27$

(2) 0.223 M KOH

Concentration of KOH = 0.223 M

As KOH is a strong base. So, it dissociates completely to give hydroxide ion and potassium ion.

So, Concentration of hydroxide ion= 0.223 M

Now we have to calculate the pOH.

$pOH=-\log [OH^-]$

$pOH=-\log (0.223)$

$pOH=0.65$

Now we have to calculate the pH.

$pH+pOH=14\\\\pH=14-pOH\\\\pH=14-0.65=13.35$

(3) 53.1 mM HCl + 0.223 M KOH

Buffer : It is defined as a solution that maintain the pH of the solution by adding the small amount of acid or a base.

It is not a buffer because HCl is a strong acid and KOH is a strong base. Both dissociates completely.

As we know that the pH of strong acid and strong base solution is always 7.

So, the given solution is not a buffer.

5 0

2 years ago