All categories

3 years ago

Please help me with chemistry

Chemistry

1 answer:

vodka [1.7K]3 years ago

7 0

Table Giving Answer

Element Atomic mass % Amount

Mg_24 24 79 18.96

Mg_25 25 10 2.5

Mg_26 26 11 2.86

Total 24.32

Discussion

The method of calculation for this table, which was done in Excel (a spread sheet) is shown below. Assume that there is 100 grams of material of "pure" magnesium. What is it's mass?

Sample Calculation

The the sample atomic mass = 24

Mass = % * sample atomic mass

Mass = 79% * 24

Mass = (79/100) * 24

Mass = 18.96

Note

The other two elements are found exactly the same as the sample calculation.

Then all you do is add the 3 masses together.

Answer

The mass of Mg to 1 decimal place is 24.3 <<<< Answer.

You might be interested in

what is the boiling point of a 0.321 m aqueous solution of NaCl. Enter your rounded answer with 3 decimal places.

Ronch [10]

Answer:

I believe the rounded place is 100.333.

3 0

2 years ago

Read 2 more answers

Trong các yếu tố sau đây: nồng độ, nhiệt độ, áp suất, diện tích tiếp xúc, chất xúc tác, có bao nhiêu yếu tố có thể ảnh hưởng tới

9966 [12]

Answer:

solubility of salt at 10 degree Celsius is 20 how does it what does it means what happens if the temperature of saturated solution is increased

Explanation:

solubility of salt at 10 degree Celsius is 20 how does it what does it means what happens if the temperature of saturated solution is increased

8 0

2 years ago

Why does the hull of an ocean -going ship rust quickly?

stepan [7]

Metal rusts when it oxidized around moisture.

4 0

2 years ago

How many grams of sodium hydroxide are needed to make 500mLs of a 0.125M NaOH solution?

zubka84 [21]

Hope this helps you.

8 0

3 years ago

You mix 200. mL of 0.400M HCl with 200. mL of 0.400M NaOH in a coffee cup calorimeter. The temperature of the solution goes from

GuDViN [60]

Answer : The enthalpy of neutralization is, 56.012 kJ/mole

Explanation :

First we have to calculate the moles of HCl and NaOH.

$\text{Moles of HCl}=\text{Concentration of HCl}\times \text{Volume of solution}=0.400mole/L\times 0.200L=0.08mol$

$\text{Moles of NaOH}=\text{Concentration of NaOH}\times \text{Volume of solution}=0.400mole/L\times 0.200L=0.08mol$

The balanced chemical reaction will be,

$HCl+NaOH\rightarrow NaCl+H_2O$

From the balanced reaction we conclude that,

As, 1 mole of HCl neutralizes by 1 mole of NaOH

So, 0.08 mole of HCl neutralizes by 0.08 mole of NaOH

Thus, the number of neutralized moles = 0.08 mole

Now we have to calculate the mass of water.

As we know that the density of water is 1 g/ml. So, the mass of water will be:

The volume of water = $200mL+200L=400mL$

$\text{Mass of water}=\text{Density of water}\times \text{Volume of water}=1g/ml\times 400mL=400g$

Now we have to calculate the heat absorbed during the reaction.

$q=m\times c\times (T_{final}-T_{initial})$

where,

q = heat absorbed = ?

$c$ = specific heat of water = $4.18J/g^oC$

m = mass of water = 400 g

$T_{final}$ = final temperature of water = $27.78^oC=273+25.10=300.78K$

$T_{initial}$ = initial temperature of metal = $25.10^oC=273+27.78=298.1K$

Now put all the given values in the above formula, we get:

$q=400g\times 4.18J/g^oC\times (300.78-298.1)K$

$q=4480.96J$

Thus, the heat released during the neutralization = -4480.96 J

Now we have to calculate the enthalpy of neutralization.

$\Delta H=\frac{q}{n}$

where,

$\Delta H$ = enthalpy of neutralization = ?

q = heat released = -4480.96 J

n = number of moles used in neutralization = 0.08 mole

$\Delta H=\frac{-4480.96J}{0.08mole}=-56012J/mole=-56.012kJ/mol$

The negative sign indicate the heat released during the reaction.

Therefore, the enthalpy of neutralization is, 56.012 kJ/mole

8 0

3 years ago