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3 years ago

4) Which indicator, when added to a solution, changes color from yellow to blue as the pH of the

Chemistry

1 answer:

Arte-miy333 [17]3 years ago

7 0

Answer:

c) bromthymol blue

Explanation:

An acidic solution has a pH value less than 7, while the pH is 7 for a neutral solution and grater than 7 for a basic solution.

Bromothymol blue is a pH indicator which is yellow in color when placed in an acid (pH under 7), the color is green in a neutral solution (pH of 7) and blue in an basic solution (pH over 7).

If bromthymol blue is added to a solution with an initial pH of 5.5 (acidic), the color would be yellow and as the pH changes to 8 (basic), the color changes to blue.

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How many moles, kmols in: 100 g of CO2, 1 litre of ethyl alcohol of density 0.789 g/cm3 and a) 1.5m3 of O2 at 25°C and 1 atm. b)

Nutka1998 [239]

Explanation:

1) Mass of carbon dioxide = 100 g

Molar mass of carbon dioxide = 44 g/mol

Moles of carbon dioxide = $\frac{100 g}{44 g/mol}=2.273 moles$

1 mol = 0.001 kmol

2.273 moles= 2.273 × 0.001 kmol = $2.273\times 10^{-3} kmol$

2) 1 liter of ethyl alcohol of density $0.789 g/cm^3$

Volume of ethyl alcohol ,V= 1 L = 1000 mL

Density of ethyl alcohol =d = $0.789 g/cm^3$

$1 cm^3=1 mL$

Mass of ethyl alcohol = m

$m=d\times V=0.789 g/cm^3\times 1000 mL=789 g$

Molar mass of ethyl alcohol = 46 g/mol

Moles of ethyl alcohol = $\frac{789 g}{46 g/mol}=17.152 mol$

$17.152 mol=17.152\times 0.001 kmol=1.7152\times 10^{-4} kmol$

3) Volume of oxygen gas,V = $1.5 m^3=1500 L$

$1 m^3= 1000 L$

Temperature of the gas = T= 25°C = 298.15 K

Pressure of the gas ,P= 1 atm

Moles of oxygen gas = n

$PV=nRT$

$n=\frac{RT}{PV}=\frac{0.0821 atm L/mol K\times 298.15 K}{1 atm\times 1500 L}=0.01632 mol$

0.01632 mol = 0.01632 × 0.001 kmol= $1.632\times 10^{-5} kmol$

4) Volume water in mixture = 1 L

Density of water = $1000 kg/m^3=\frac{1,000,000 g}{1000 L}=1000 g/L$

Mass of water = $1000 g/L\times 1 L = 1000 g$

Volume of alcohol = 2.5 L

Density of alcohol = $789 kg/m^3=\frac{789000 g}{1000 L}=789 g/L$

Mass of alcohol = $789 g/L\times 2.5 L = 1972.5 g$

Mass of mixture = 1000 g + 1972.5 g = 2972.5 g

Mass percentage of water :

$\frac{1000 g}{2972.5 g}\times 100=33.64\%$

Mass percentage of alcohol :

$\frac{1972.5 g}{2972.5 g}\times 100=66.36\%$

Moles of water :

$n_1=\frac{1000 g}{18 g/mol}=55.55 mol$

Moles of alcohol =

$n_2=\frac{1972.5 g}{46 g/mol}=42.88 mol$

Mole fraction of water :

$\chi_1=\frac{n_1}{n_1+n_2}=\frac{55.55 mol}{55.55 mol+42.88 mol}=0.5644$

Mole fraction of alcohol :

$\chi_2=\frac{n_2}{n_1+n_2}=\frac{42.88 mol}{55.55 mol+42.88 mol}=0.4356$

3 0

2 years ago

3. Given the following equation:

miskamm [114]

Answer:

4.767 grams of KCl are produced from 2.50 g of K and excess Cl2

Explanation:

The balanced equation is

2 K+ Cl2 --->2 KCI

Here the limiting agent is K. Hence, the amount of KCl will be calculated as per the mass of 2.50 gram of K

Mass of one atom/mole of potassium is 39.098 grams

Number of moles is 2.5 grams = $\frac{2.5}{39.098} = 0.064$

So, 2 moles of K produces 2 moles of KCL

0.064 moles of K will produces 0.064 moles of KCl

Mass of one molecule of KCl is 74.5513 g/mol

Mass of 0.064 moles of KCl is 4.767 grams

4 0

2 years ago

The behavior of the _______ elements is not highly predictable.

Lera25 [3.4K]

C. transition, as they show variable oxidation states.

5 0

3 years ago

Read 2 more answers

I have to do an experiment about reaction rates, and i need to have things to dissolve..

Leona [35]

Answer:

salt ( with food coloring)

sand

sodium chloride

coffee

flour

oil

vinegar

different types of pancake mix

3 0

1 year ago

Silver is produced as a byproduct of gold

VashaNatasha [74]

Answer:

Element Properties

atomic number 47

atomic weight 107.868

melting point 960.8 °C (1,861.4 °F)

boiling point 2,212 °C (4,014 °F)

specific gravity 10.5 (20 °C [68 °F])

oxidation states +1, +2, +3

electron configuration [Kr]4d105s1

hope that helps

4 0

2 years ago