Calcium is a native metal. t or f

Washing soda is a hydrate of sodium carbonate. Elemental analysis of a sample of washing soda gave 4.20% C and 7.05% H. What is

kozerog [31]

Answer:

Na₂CO₃ · 10H₂O

Explanation:

The formula for sodium carbonate hydrate is:

Na₂CO₃ · xH₂O

The unknown "x" is the number of water molecules contained in the hydrate.

To find "x" we have to use the hydrogen percentage in the sample, 7.05 % H.

First we calculate the molecular weight of Na₂CO₃ · xH₂O:

molecular weight of Na₂CO₃ · xH₂O = 23 × 2 + 12 + 16 × 3 + 18x

molecular weight of Na₂CO₃ · xH₂O = 106 + 18x g/mole

Now we devise the fallowing reasoning tanking in account 1 mole of Na₂CO₃ · xH₂O:

if in 106 + 18x grams of Na₂CO₃ · xH₂O we have 2x grams of hydrogen

then in 100 grams of Na₂CO₃ · xH₂O we have 7.05 grams of hydrogen

106 + 18x = (100 × 2x) / 7.05

106 + 18x = 28.4x

106 = 28.4x - 18x

106 = 10.4x

x = 106 / 10.4

x = 10.2 ≈ 10

The formula for the washing soda is Na₂CO₃ · 10H₂O.

5 0

3 years ago

Although both N2 and 02 are naturally present in the air we breathe, high levels of NO and NO2 in the atmosphere occur mainly in

joja [24]

Answer:

(a) Increasing the temperature adds heat which is a reactant shifting the equilibrium rightwards.

(b) Pressure has no effect since the change in the number of moles is zero.

Explanation:

Hello,

In this case, one could represent the given reaction as:

$N_2(g)+O_2(g)+ \Delta _rH \leftrightarrow 2NO$

Since it is endothermic. Thus, solving the (a) statement, one identifies the heat as a reagent, that is why the reaction cools down as it progress, therefore, by increasing the temperature, heat is added, that is, a reagent is added, which shifts the equilibrium rightwards, in other words, more NO is produced so its concentration increases.

Furthermore, for the (b) statement, since the change in the number of moles is zero, based on the stoichiometric coefficients as shown below:

$\Delta \nu =2-1-1=0$

Such value implies that the pressure has no effect on the concentration, taking into account the following form of the law of mass action:

$Kp=Kc(RT)^{\Delta \nu }$

Thus, since $\Delta \nu =0$ , $Kp=Kc$ , so no effect in concentration is due to the pressure.

Best regards.

6 0

3 years ago

A 38.6 kg marble slab is shown above. What is it’s density? Give you’re answer to the nearest tenth

kykrilka [37]

Answer:

Density, $d=24.68\ g/cm^3$

Explanation:

Given that,

Mass of marble slab is 38.6 kg or 38600 g

The dimensions of the slab is 23 cm × 17 cm ×4 cm

We know that the density of an object is given in terms of its mass volume as follows :

$d=\dfrac{\text{mass}}{\text{volume}}\\\\d=\dfrac{38600\ g}{1564\ cm^3}\\\\d=24.68\ g/cm^3$

So, the density of the marble slab is $24.68\ g/cm^3$

4 0

4 years ago

4. Which statement is true?

Marta_Voda [28]

Answer:

d

Explanation:

Hope this helps and have a great day!!!

6 0

3 years ago

What is the average isotope mass?

Aleksandr [31]

Answer:

the atomic mass of an element is the average mass of the atoms of an element measured in atomic mass unit (amu, also known as daltons, D). The atomic mass is a weighted average of all of the isotopes of that element, in which the mass of each isotope is multiplied by the abundance of that particular isotope

Explanation:

Average atomic mass = f1M1 + f2M2 + … + fnMn where f is the fraction representing the natural abundance of the isotope and M is the mass number (weight) of the isotope. The average atomic mass of an element can be found on the periodic table, typically under the elemental symbol.

8 0

3 years ago

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