I NEED HELP!!

ANSWER FAST PLZZZ!!!!!!!!!!!!!

Anestetic [448]

Answer: D. test tubes, thermometers, etc

I think this is the correct answer. Sorry if it is not.

Explanation:

6 0

3 years ago

A chemist dissolves 699. mg of pure hydrobromic acid in enough water to make up 180. mL of solution. Calculate the pH of the sol

Sedaia [141]

Answer: 1.32

Explanation:

First, we must obtain the molar mass of HBr. After that, we try to obtain the concentration of the hydrobromic acid from the formula n=CV since the volume of solution and mass of acid was provided. Recall that n=m/M. If the concentration of acid is thus obtained, we make use of the fact that the concentration of H+ in the acid is equal to the molar concentration of HBr to obtain the pH. The pH is the negative logarithm of the concentration we obtained in the initial step.

8 0

3 years ago

Why isn’t K+ H2O —> KOH + H2 not balanced?

alex41 [277]

Answer:

The obtained result indicates that the hydrogen atom is not equal on both sides. Thus the reaction is not balanced.

Explanation:

6 0

2 years ago

Order the units or geologic time from the longest to the shortest era, period, epoch, eon.

sweet [91]

Answer:

The geological time from the longest to the shortest are:

Eon,
Era,
Period and,
Epoch.

3 0

3 years ago

Can someone help on five and six I am at a loss on how to solve it

Bumek [7]

Answer:

Q5.

a} Yes , All Cl2 get eliminated by adding 170 g of sodium thiosulfate .

b) There excess of Sodium thiosulfate by 2.637 g

Q6.

a) Mass = 162 g Sodium bicarbonate

b)Volume of Ammonia remain after the reaction = 0.086 x 24.8 = 1.60 L

Explanation:

Points to be considered :

There is a difference between STP and SATP :

STP = Standard Temperature and Pressure (273.15 K and 1 atm)

1 mole of gas at STP = 22.4 L

SATP = Standard Ambient Temperature and Pressure (293.15 K and 1 atm)

1 mole of gas at SATP = 24.8 L

$moles = \frac{Given\ mass}{Molar\ mass}$

Number of moles of gas at SATP :

$moles = \frac{Given\ Volume}{24.8L}$

Q5.

First, calculate the number of moles of Cl2 and thiosulfate present in the reaction :

Volume of Cl2 = 105 L

Moles of Cl2 =

$moles = \frac{Given\ Volume}{24.8}$

$moles = \frac{105}{24.8}$

Moles of Cl2 in Reaction medium = 4.2338 mole

Mass of Sodium thiosulfate = 170 g

Molar mass of thiosulfate = 158.11 g/mol (theoretical value)

$moles = \frac{170}{158.11}$

= 1.075

Moles of Sodium Thiosulfate in Reaction medium = 1.075 mole

To check whether the given moles of Cl2 and sodium thiosulfate satisfy theoretical values :

Consider the Given reaction and apply law of conservation of mass

$4Cl_{2}+Na_{2}S_{2}O_{3}+5H_{2}O\rightarrow 2NaHSO_{3}+8HCl$

$Na_{2}S_{2}O_{3}$ = sodium thiosulfate

This equation indicates ,

4 moles of Cl2 require = 1 mole of sodium thiosulfate

1 mole of Cl2 require =

$\frac{1}{4}$ of sodium thiosulfate = 0.25

4.2338 mole of Cl2 should need = 0.25 x 4.2338

= 1.058 mole of sodium thiosulfate

Required Thiosulfate = 1.058 mole

But,

Moles of Sodium Thiosulfate in Reaction medium = 1.075 mole

So , extra moles of Sodium Thiosulfate is present in the reaction by

= 1.075 - 1.0589 = 0.0166 mol

Molar mass of sodium thiosulfate = 158 .11 g/mol

$Mass =0.166\times 158.11$

= 2.637 g

a} .Yes , All Cl2 get eliminated by adding 170 g of sodium thiosulfate .

b) There excess of Sodium thiosulfate by 2.637 g

Q6.

Volume of ammonia = 50.0 L

Moles of Ammonia ,

$moles = \frac{Given\ Volume}{24.8L}$

$moles = \frac{50}{24.8L}$

= 2.016 moles

Moles of CO2 =

Mass of CO2 = 85.0 g

Molar mass = 44 g/mol

$moles = \frac{Given\ mass}{Molar\ mass}$

$moles = \frac{85.0}{44}$

= 1.932 mol of CO2

Now check the law of conservation of mass :

$NaCl + NH_{3} + CO_{2} +H_{2}O\rightarrow NaHCO_{3} +NH_{4}Cl$

According to above equation ,

1 mole of CO2 Needs = 1 mole of NH3

1.93 mol of CO2 need = (1 x 1.93) mol

1.93 mol of CO2 need = 1.93 mol of ammonia

Available ammonia = 2.016 mol

So Ammonia is in excess by:

= 2.016 - 1.93 mol

= 0.086 mol

Volume at SATP is calculated by

$V =mole\times 24.8$

Volume of Ammonia remain after the reaction = 0.086 x 24.8

= 2.1104 L

= 2.10 L

CO2 is the limiting reagent and governs the product formation :

Molar mass of NaHCO3 = 84.007 g/mol

1 mole of CO2 Needs = 1 mole of NaHCO3 = 84.007

1.93 mol of CO2 need = 1.93 x 84.007 mol

= 162.133 g of Sodium bicarbonate

= 162 g Sodium bicarbonate

Note : The answers are present in rounded figures .

6 0

3 years ago