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Zepler [3.9K]
2 years ago
8

Can anyone please answer questions 3 and 4 I’ll give the brainiest!

Chemistry
1 answer:
mel-nik [20]2 years ago
4 0

Answer:

1.Phenolphthalein

2.Method

a.Use the pipette and pipette filler to add 25 cm 3 of alkali to a clean conical flask.

b.Add a few drops of indicator and put the conical flask on a white tile.

c.Fill the burette with acid and note the starting volume.

d.Slowly add the acid from the burette to the alkali in the conical flask, swirling to mix.

Explanation:

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In which of the following substances does sharing of electrons between two atoms occur?
Ilya [14]

Answer:

Explanation:

CO2

3 0
3 years ago
A student is asked to seperate two liquids. Liquid A boils at 100°c and liquid B boils at 65°c. The student sets up a fractional
julsineya [31]

Answer:

B

Explanation:

because B has a lower bp it needs less time and energy to turn into vapour and is collected into the condenser first

3 0
3 years ago
A sample of methane at a pressure of 1.00 atm and a temperature of 93.1 K is heated at constant pressure to a temperature of 158
Zinaida [17]

Answer:

b. The final state of the substance is a gas.

d. The sample is initially a liquid. One or more phase changes will occur.

Explanation:

Methane has the following properties:

  • Normal melting point: 90.7 K
  • Normal boiling point: 111.65 K

*"Normal" refers to normal pressure (1 atm).

According to this, we can affirm:

  • Below 90.7 K, methane is solid.
  • Between 90.7 K and 111.65 K, methane is liquid.
  • Above 111.65 K, methane is gas.

<em>A sample of methane at a pressure of 1.00 atm and a temperature of 93.1 K is heated at constant pressure to a temperature of 158 K. Which of the following are true? Choose all that apply.</em>

<em>a. The liquid initially present will solidify.</em>  FALSE. The liquid will vaporize.

<em>b. The final state of the substance is a gas.</em>  TRUE.

<em>c. The sample is initially a solid.</em>  FALSE. The sample is initially a liquid.

<em>d. The sample is initially a liquid. One or more phase changes will occur. </em>TRUE.

4 0
3 years ago
What type of reaction is represented by the following example? 2CO2 (g) + 4H2O (l) + 1452 kJ 2CH3OH (l) (g) + 3O2 (g) exothermic
Elodia [21]

endothermic  

I hope this helped :)

8 0
3 years ago
Read 2 more answers
If the atmospheric pressure in the laboratory is 1.2 atm, how many moles of gas were in each syringe? (Hint: Choose one volume a
Naily [24]

Answer:

A: 2.525 x 10-4 mol

B: 2.583 x 10-4 mol

Explanation:

Part A:

Data Given:

. Temperature of water (H2O) = 21.3°C

Convert Temperature to Kelvin

T = °C + 273

T = 21.3 + 273 = 294.3 K

volume of (H2O) gaseous state = 5.1 mL

Convert mL to liter

1000 mL = 1L

5.1 ml = 5.1/1000 = 0.0051 L

Pressure = 1.2 atm

. no. of moles = ?

Solution

no. of moles can be calculated by using ideal gas formula

PV = nRT

Rearrange the equation for no. of moles

n=PV/RT......... (1)

where

P = pressure

V = Volume

T= Temperature

n = Number of moles

R = ideal gas constant

where

R = 0.08206 L.atm/ mol. K

Now put the value in formula (1) to calculate no. of moles of

n = 1.2 atm x 0.0051 L / 0.08206 L.atm.mol-1. K-1 x 294.3 K

n = 0.0061 atm.L / 24.162 L.atm.mol-1

n = 2.525 x 10-4 mol

no. of moles of gas (H2O) = 2.525 x 10-4 mol

Part B:

Data Given:

Temperature of water (H2) = 21.3°C

Convert Temperature to Kelvin

T = "C + 273

T= 21.3 + 273 = 294.3 K

volume of (H2) gas = 5.2 mL

Convert mL to liter

1000 mL = 1 L

5.2 ml = 5.2/1000 = 0.0052 L

Pressure = 1.2 atm

. no. of moles = ?

Solution

no. of moles can be calculated by using ideal gas formula

PV = nRT

Rearrange the equation for no. of moles

n= PV / RT......... (1)

where

P = pressure

V = Volume

T= Temperature

n = Number of moles

R = ideal gas constant

where

R = 0.08206 L.atm/mol. K

Now put the value in formula (1) to calculate no. of moles of

n = 1.2 atm x 0.0052 L/0.08206 L.atm.mol-1. K-1 x 294.3 K

n = 0.0062 atm.L/ 24.162 L.atm.mol-1

n = 2.583 x 10-4 mol

I

no. of moles of gas (H2) = 2.583 x 10-4 mol

8 0
3 years ago
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