A 2.0-g sample of washing soda, Na CO • 10H O, has carbon atoms. How many oxygen atoms are present in 2.0g of washing soda?

imagine you or your family member experienced a medical emergency. explain two reasons when and why confidentiality would be imp

Hatshy [7]

One reason confidentiality would be important at a time of a medical emergency is if the patient didn't want people to know about the emergency so that they wouldn't worry. Another reason is for instance if that medical emergency was something that the patient considered embarrassing then they wouldn't want people to know.

5 0

2 years ago

How many grams of antifreeze C2H4(OH)2 would be required per 500 g of water to prevent the water from freezing at a temperature

Wewaii [24]

Answer:

333.7 g.

Explanation:

The depression in freezing point of water (ΔTf) due to adding a solute to it is given by: ΔTf = Kf.m.

Where, ΔTf is the depression in water freezing point (ΔTf = 20.0°C).

Kf is the molal freezing point depression constant of the solvent (Kf = 1.86 °C/m).

m is the molality of the solution.

∴ m = ΔTf/Kf = (20.0°C)/(1.86 °C/m) = 10.75 m.

molaity (m) is the no. of moles of solute per kg of the solvent.

∵ m = (no. of moles of antifreeze C₂H₄(OH)₂)/(mass of water (kg))

∴ no. of moles of antifreeze C₂H₄(OH)₂ = (m)(mass of water (kg)) = (10.75 m)(0.5 kg) = 5.376 mol.

∵ no. of moles = mass/molar mass.

∴ mass of antifreeze C₂H₄(OH)₂ = no. of moles x molar mass = (5.376 mol)(62.07 g/mol) = 333.7 g.

5 0

2 years ago

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

2 years ago

A sample of an unknown compound was decomposed and found to be composed of 1.36 mol oxygen, 4.10 mol hydrogen, and 2.05 mol carb

Flura [38]

Answer:

C3H6O2

Explanation:

To find the empirical formula of the compound, we divide the amount in moles of each of the elements by the amount in mole of the element with the smallest number of mole. In this question, the element with the smallest number of moles is oxygen with 1.36 mole. Hence, we divide the number of moles of each element by this.

H = 4.10/1.36 = 3

O = 1.36/1.36 = 1

C = 2.05/1.36 = 1.5

We then multiply through by 2 to yield the compound with the empirical formula C3H6O2

7 0

2 years ago

NH4NO3, whose heat of solution is 25.7 kJ/mol, is one substance that can be used in cold pack. If the goal is to decrease the te

makvit [3.9K]

Answer:

There are necessaries 35,2g of NH₄NO₃ per 100,0g of water to decrease the temperature of the solution from 25,0°C to 5,0°C

Explanation:

To decrease the temperature of the solution there are necessaries:

4,184J/g°C×(5,0°C-25,0°C)×(100,0g+X) = -Y

8368J + 83,68J/gX = Y (1)

Where x are grams of NH₄NO₃ you need to add and Y is the energy that you need to decrease the heat.

Also, the energy Y will be:

Y = 25700J/mol× $\frac{1mol}{80,043g}$ X

Y = 321J/g X (2)

Replacing (2) in (1)

8368J + 83,68J/g X = 321J/g X

8363J = 237,32J/gX

X = 35,2g

Thus, there are necessaries 35,2g of NH₄NO₃ per 100,0g of water to decrease the temperature of the solution from 25,0°C to 5,0°C

I hope it helps!

6 0

2 years ago