All categories

3 years ago

A sample of helium gas has a volume of 2.75 L at STP. How many grams of He are present?

1 answer:

4 0

Molar mass He = 4.0 g/mol

1 mole --------- 22.4 L ( at STP )
? mole ---------- 2.75 L

2.75 x 1 / 22.4 => 0.1227 moles

1 mole He ------------ 4.0 g
0.1227 moles --------- ?

0.1227 x 4.0 / 1 => 0.4908 g of He

hope this helps!

You might be interested in

Determine the rate law, including the values of the orders and rate law constant, for the following reaction using the experimen

murzikaleks [220]

Answer: Rate law is, R= 6.02[A]¹[B]²

Explanation in attached image

5 0

3 years ago

Which of the following is most likely to be covalent? MgO CO CaO BaO

Kisachek [45]

Answer:

CaO

Explanation:

CaO is the only compound that is a non-metal and a non-metal. The rest of the compounds are ionic, or metal and non-metal.

8 0

3 years ago

1. Calculate the percent oxygen in H2SO4.

Mashutka [201]

I believe the answer is 65.254%

6 0

3 years ago

I need help with this

cricket20 [7]

Answer:

#TEAM BOB

FOR BOB!!!!!!!

░░░░░▐▀█▀▌░░░░▀█▄░░░

░░░░░▐█▄█▌░░░░░░▀█▄░░

░░░░░░▀▄▀░░░▄▄▄▄▄▀▀░░

░░░░▄▄▄██▀▀▀▀░░░░░░░

░░░█▀▄▄▄█░▀▀░░

░░░▌░▄▄▄▐▌▀▀▀░░ Dis is Bob

▄░▐░░░▄▄░█░▀▀ ░░

▀█▌░░░▄░▀█▀░▀ ░░

░░░░░░░▄▄▐▌▄▄░░░

░░░░░░░▀███▀█░▄░░ Help Bob

░░░░░░▐▌▀▄▀▄▀▐▄░░ take over

░░░░░░▐▀░░░░░░▐▌░░ brainly.

░░░░░░█░░░░░░░░█░

Copy and paste to help Bob.

We can do it together!#TEAM BOB

FOR BOB!!!!!!!

░░░░░▐▀█▀▌░░░░▀█▄░░░

░░░░░▐█▄█▌░░░░░░▀█▄░░

░░░░░░▀▄▀░░░▄▄▄▄▄▀▀░░

░░░░▄▄▄██▀▀▀▀░░░░░░░

░░░█▀▄▄▄█░▀▀░░

░░░▌░▄▄▄▐▌▀▀▀░░ Dis is Bob

▄░▐░░░▄▄░█░▀▀ ░░

▀█▌░░░▄░▀█▀░▀ ░░

░░░░░░░▄▄▐▌▄▄░░░

░░░░░░░▀███▀█░▄░░ Help Bob

░░░░░░▐▌▀▄▀▄▀▐▄░░ take over

░░░░░░▐▀░░░░░░▐▌░░ brainly.

░░░░░░█░░░░░░░░█░

Copy and paste to help Bob.

We can do it together!#TEAM BOB

FOR BOB!!!!!!!

░░░░░▐▀█▀▌░░░░▀█▄░░░

░░░░░▐█▄█▌░░░░░░▀█▄░░

░░░░░░▀▄▀░░░▄▄▄▄▄▀▀░░

░░░░▄▄▄██▀▀▀▀░░░░░░░

░░░█▀▄▄▄█░▀▀░░

░░░▌░▄▄▄▐▌▀▀▀░░ Dis is Bob

▄░▐░░░▄▄░█░▀▀ ░░

▀█▌░░░▄░▀█▀░▀ ░░

░░░░░░░▄▄▐▌▄▄░░░

░░░░░░░▀███▀█░▄░░ Help Bob

░░░░░░▐▌▀▄▀▄▀▐▄░░ take over

░░░░░░▐▀░░░░░░▐▌░░ brainly.

░░░░░░█░░░░░░░░█░

Copy and paste to help Bob.

We can do it together!

Explanation:

7 0

2 years ago

Read 2 more answers

In the laboratory, a general chemistry student measured the pH of a 0.486 M aqueous solution of triethanolamine, C6H15O3N to be

STatiana [176]

Answer:

Kb = 6.22x10⁻⁷

Explanation:

Triethanolamine, C₆H₁₅O₃N, is in equilibrium with water:

C₆H₁₅O₃N(aq) + H₂O(l) ⇄ C₆H₁₅O₃NH⁺(aq) + OH⁻(aq)

Kb is defined from concentrations in equilibrium, thus:

Kb = [C₆H₁₅O₃NH⁺] [OH⁻] / [C₆H₁₅O₃N]

The equilibrium concentration of these compounds could be written as:

[C₆H₁₅O₃N] = 0.486M - X

[C₆H₁₅O₃NH⁺] = X

[OH⁻] = X

pH is -log [H⁺], thus, [H⁺] = 10^-pH = 1.820x10⁻¹¹M

Also, Kw = [OH⁻] ₓ [H⁺];

1x10⁻¹⁴ = [OH⁻] ₓ [H⁺]

1x10⁻¹⁴ = [OH⁻] ₓ [1.820x10⁻¹¹M]

5.495x10⁻⁴M = [OH⁻], that means X = 5.495x10⁻⁴M

Replacing in Kb formula:

Kb = [5.495x10⁻⁴M] [5.495x10⁻⁴M] / [0.486M-5.495x10⁻⁴M]

Kb = 6.22x10⁻⁷

5 0

3 years ago