All categories

3 years ago

How to solve this!! plz , i have an exam tommorow

Chemistry

2 answers:

Soloha48 [4]3 years ago

5 0

Was .08 off its 4.08 like that guy explained

Serjik [45]3 years ago

3 0

First change the grams to moles using the molar mass of the compound which can be calculated by adding the mass of each atom from the periodic table.

the use mole-mole ration from the given reaction equation. then convert the moles to mass back again using the molar mass of that compound.

molar mass NaF= 42.0 g/ mol
molar mass MgF2= 62.3 g/ mol

moles NaF= 5.5 / 42.0 g= 0.131 mol NaF

2 moles NaF = 1 mole MgF2

so 0.131 mol NaF/ 2= 0.0655 mole MgF2

grams MgF2= 0.0655 moles x 62.3= 4.08 grams

or simplified

5.5 g NaF (1 mol NaF/ 42.0 g) (1 mol MgF2/ 2 mol NaF) (62.3 g/ 1 mol MgF2)= 4.08 grams

You might be interested in

A certain substance X has a normal freezing point of -10.1 degree C and a molal freezing point depression constant K_f = 5.32 de

kirill115 [55]

Answer: $-15.4^00C$

Explanation:

$T^0_f-T_f=i\times k_f\times \frac{w_2\times 1000}{M_2\times w_1}$

where,

$T_f$ = boiling point of solution = ?

$T^o_f$ = boiling point of solvent (X) = $-10.1^oC$

$k_f$ = freezing point constant = $5.32^oC/kgmol$

m = molality

i = Van't Hoff factor = 1 (for non-electrolyte like urea)

= mass of solute (urea) = 29.82 g

= mass of solvent (X) = 500.0 g

$M_2$ = molar mass of solute (urea) = 60 g/mol

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

$(-10.1-(T_f))^oC=1\times (5.32^oC/m)\times \frac{(29.82g)\times 1000}{60\times (500.0g)}$

$T_f=-15.4^0C$

Therefore, the freezing point of solution is $-15.4^0C$

7 0

3 years ago

Rank the following substances in order from most soluble in water to least soluble in water: methane, CH4; 2-butanol, C4H9OH; ma

Taya2010 [7]

Answer: The given substances are placed in order from most soluble in water to least soluble in water as follows.

$MgCl_{2}$ > $C_{4}H_{9}OH$ > $C_{3}H_{8}$ > $CH_{4}$

Explanation:

It is known that like dissolves like which means a polar compound will be soluble in a polar solvent. And, a non-polar compound will be soluble in non-polar solvent.

Ionic compounds are soluble in polar solvent like water. For example, $MgCl_{2}$ is an ionic compound and it is readily soluble in water.

2-butanol ( $C_{4}H_{9}OH$ ) is also a polar compound and it will also dissolve in water but to a lesser extent as compared to magnesium chloride.

Whereas both methane and propane are non-polar in nature. But as propane is larger in size as compared to methane so, it will be slightly more soluble in water as compared to methane.

Thus, we can conclude that the given substances are placed in order from most soluble in water to least soluble in water as follows.

$MgCl_{2}$ > $C_{4}H_{9}OH$ > $C_{3}H_{8}$ > $CH_{4}$

5 0

3 years ago

What is the relationship between the food we eat and the energy in our body

zalisa [80]

The food we eat is can sometimes bo bad or good but it relates to the energy in our because it turns into energy and then we have strenght to do something and stay healthy.

8 0

4 years ago

A 25.225 g sample of aqueous waste leaving a fertilizer manufacturer contains ammonia. The sample is diluted with 75.815 g of wa

Rudik [331]

Answer:

1.43 (w/w %)

Explanation:

HCl reacts with NH3 as follows:

HCl + NH3 → NH4+ + Cl-

<em>1 mole of HCl reacts per mole of ammonia.</em>

Mass of NH3 is obtained as follows:

<em>Moles HCl:</em>

0.02999L * (0.1068mol / L) = 3.203x10-3 moles HCl = <em>Moles NH3</em>

<em>Mass NH3 in the aliquot:</em>

3.203x10-3 moles NH3 * (17.031g / mol) = 0.0545g.

Mass of sample + water = 22.225g + 75.815g = 98.04g

Dilution factor: 98.04g / 14.842g = 6.6056

That means mass of NH3 in the sample is:

0.0545g * 6.6056 = 0.36g NH3

Weight percent is:

0.36g NH3 / 25.225g * 100

6 0

3 years ago

What functions of cells can be affected by a mutation?

Colt1911 [192]

It changes the rate of growth that cells usually undergo.

6 0

3 years ago