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Umnica [9.8K]
3 years ago
5

How many moles of Kr are contained in 398 mg of Kr?

Chemistry
1 answer:
bagirrra123 [75]3 years ago
8 0
The mass of 1 mole of an element is its atomic weight on the Periodic Table in grams.

1g = 1000mg

The mass of 1 mole of Kr = 83.80g Kr

Convert mg Kr to g Kr.

398mg Kr x (1g/1000mg) = 0.398g Kr

Convert g Kr to mol Kr.

0.398g Kr x (1mol Kr/83.80g Kr) = 4.75x10-3mol Kr
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How many grams of NaOH do you need to dissolve to make 1.55 Liters of a 1.55 Molar solution?
ale4655 [162]

Answer:

Mass = 96g

Explanation:

Molarity = number of moles/volume of solvent

According to the provided information, volume = 1.55L, Molarity = 1.55M

number of moles (n) = molarity × volume

n = 1.55 × 1.55

n = 2.4025

n = 2.40mol

For NaOH, molar mass = 23 + 16 + 1 = 40g/mol

mole = mass/molar mass

Mass = molar mass × mole

Mass = 40 × 2.40

Mass = 96g

6 0
3 years ago
which of the following types of stars would be hottest in temperature A main sequence B whitedwarf C red giant D Red supergiant
nalin [4]

Answer:

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Explanation:

3 0
3 years ago
Determine the molecular formula of decene, which has an empirical formula of CH2 and a molar mass of 140.27 g/mol.
mart [117]

Answer:

Molecular formula = C₁₀H₂₀

Explanation:

Given data:

Empirical formula = CH₂

Molar mass = 140.27 g/mol

Molecular formula = ?

Solution:

Molecular formula = n (empirical formula)

n = molar mass of compound / empirical formula mass

Now we will calculate the empirical formula mass.

CH₂ = 12 × 1 + 1× 2

CH₂ = 12 +2

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n = 140.27 / 14

n = 1 0

Molecular formula = n (empirical formula)

Molecular formula = 10 (CH₂)

Molecular formula = C₁₀H₂₀

5 0
3 years ago
How many quarters have the same value as 85 dimes? Use the equality 4 quarters = 10 dimes.?
marissa [1.9K]
There's 34 quarters in 85 dimes.
If you divide 10 by 2 you get 5, every 2 quarters is 5 dimes.
5 0
3 years ago
Read 2 more answers
How do u do this. I'm really confused
Kaylis [27]
Are you wanting us to answer all of them I will tell you in the comment box the answer ok
8 0
4 years ago
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