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

Mercury thermometers work because mercury ____ when it is warmed

kap26 [50]

Mercury expands when it is heated. This process is called thermal expansion.

5 0

3 years ago

A solution of phosphoric acid was made by dissolving 10.8 g of H3PO4 in 133.00 mL of water. The resulting volume was 137 mL. Cal

Nesterboy [21]

Answer:

Density is: 1.05 g/ml

Mole fraction solute: 0.015

Mole fraction solvent: 0.095

Molarity: 0.80 M

Molality: 0.82 m

Explanation:

A typical excersise of solution.

It is more confortable to make a table for this.

| masss | volume | mol

solute | | |

solvent | | |

solution | | |

Let's complete, what we have.

| masss | volume | mol

solute | 10.8g | |

solvent | | 133 mL |

solution | | 137 mL |

We can first, know how many moles are 10.8 g

Molar Mass H3PO4 = 97.99 g/mol

Mass / Molar mass = mol

10.8 g / 97.99 g/m = 0.110 mol

Density of water is 1 g/ml (it is a very knowly value)

From this data, we can know water mass, solvent.

Density = mass / volume

1 g/ml = mass / 133 mL

Mass = 133 g

We can also have the moles, by the molar mass of water 18 g/m

133 g / 18 g/m = 7.39 mol

| masss | volume | mol

solute | 10.8g | | 0.110 mol

solvent | 133g | 133 mL | 7.39 mol

solution | 143.8g | 137 mL | 7.50 mol

Mass of solution will be solute mass + solvent mass

Moles of solution will be solute moles + solvent moles

Now we can calculate everything.

Molarity means mol of solute in 1 L of solution. (mol/L)

We have to convert 137 mL in L (/1000)

0.137L so → 0.110 m / 0.137L = 0.80 M

Molality means mol of solute in 1kg of solvent.

We have to convert 133g in kg (/1000)

0.133 kg so → 0.110 m/0.133 kg = 0.82 m

Density is mass / volume

Solution density will be solution mass / solution volume

143.8 g/137 mL = 1.05 g/m

Molar fraction is : solute moles / total moles or solvent moles/total moles.

You can also (x 100%) to have a percent of them.

Remember sum of molar fraction = 1

Molar fraction of solute = 0.110 mol / 7.50mol = 0.015

Molar fraction of solvent = 7.39 mol / 7.50 mol = 0.985

5 0

3 years ago

Sugar dissolving in warm water is chemical or phyiscal change

BlackZzzverrR [31]

Hey there! Great question;) Answer:Physical change Explanation: When sugar mixes with water, at the end, the chemical formulas are the same. Nothing has changed! I hope this helps;)

5 0

3 years ago

Paano mo mapapanatili na gumagana ang iyong negosyo sa gitna ng pandemic na ito?

gogolik [260]

Tingnan ang pinakamahuhusay na kagawian at patnubay sa pampublikong kalusugan para mapanatiling ligtas ang iyong mga customer at tauhan.

HOPE IT HELPS:)

PLS FOLLOW:)

#BRAINLIEST

5 0

2 years ago

Read 2 more answers

Write balanced chemical equation for the reactions used to prepare each of the following compounds from the given starting mater

creativ13 [48]

Explanation:

A balanced chemical equation is defined as the one that contains same number of atoms on both reactant and product side.

Whereas a chemical reaction that brings change in oxidation state of the reacting species is known as a redox reaction.

When there occurs decrease in oxidation number of an element then it shows the element has been reduced. And, if there occurs an increase in oxidation state of an element then it means the element has been oxidized.

(a) The reaction between nitrogen and hydrogen to form ammonia will be as follows.

$N_{2} + 3H_{2} \rightarrow 2NH_{3}$

So here, oxidation state of nitrogen is changing from 0 to -3. Whereas oxidation state of hydrogen is changing from 0 to +3.

Reaction between ammonia and nitric acid will be as follows.

$NH_{3} + HNO_{3} \rightarrow NH_{4}NO_{3}$

Since, it is a combination reaction. Therefore, no change in oxidation state of reacting species is taking place.

(b) Reaction for conversion of liquid bromine to hydrogen bromide is as follows.

$H_{2}(g) + Br_{2}(l) \rightarrow 2HBr(g)$

Here, oxidation state of hydrogen is changing from 0 to +1. Therefore, oxidation of hydrogen is taking place. On the other hand, oxidation state of bromine is changing from zero to -1. Therefore, reduction of bromine is taking place.

(c) Reaction between Zn and S will be as follows.

$Zn(s) + S(s) \rightarrow ZnS(s)$

Here, oxidation state of zinc is changing from 0 to +2. Hence, oxidation of zinc is taking place.

Oxidation state of sulfur is changing from 0 to -2. Therefore, reduction of sulfur is taking place.

7 0

3 years ago