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2 years ago

How many moles of KCIO3 are in 5 g of KClO3?

2 answers:

7 0

1. Calculate the molar mass of KClO3: 39.098+ 35.453 + 3(16) = 122.551 g KClO3
2. 5gKClO3 x 1mol KClO3/ 122.551g KClO3 = 0.041mol of KClO3

STatiana [176]2 years ago

6 0

Molar mass of KClO3

$\\ \tt\hookrightarrow 39+35+3(16)$

$\\ \tt\hookrightarrow 74+48$

$\\ \tt\hookrightarrow 122g/mol$

Now

$\\ \tt\hookrightarrow No\:of\:moles=\dfrac{Given\:mass}{Molar\:mass}$

$\\ \tt\hookrightarrow No\:of\:moles=\dfrac{5}{122}$

$\\ \tt\hookrightarrow No\:of\:moles=0.04mol$

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Butoxors [25]

Answer:

Its the first second and the fourth

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3 years ago

A sample contains 16 mg of polonium-218. After 12 minutes, the sample will contain 1.0 mg of polonium-218. What is the half life

mariarad [96]

Answer:

Half-life = 3 minutes

Explanation:

Using the radioactive decay equation we can solve for reaction constant, k. And by using:

K = ln2 / Half-life

We can find half-life of polonium-218

Radioactive decay:

Ln[A] = -kt + ln [A]₀

Where:

[A] could be taken as mass of polonium after t time: 1.0mg

k is Reaction constant, our incognite

t are 12 min

[A]₀ initial amount of polonium-218: 16mg

Ln[A] = -kt + ln [A]₀

Ln[1.0mg] = -k*12min + ln [16mg]

-2.7726 = - k*12min

k = 0.231min⁻¹

Half-life = ln 2 / 0.231min⁻¹

<h3>Half-life = 3 minutes</h3>

5 0

2 years ago

A sample of propane(c3h8)has 3.84x10^24 H atoms.

deff fn [24]

Answer:

A) 14. 25 × 10²³ Carbon atoms

B) 34.72 grams

Explanation:

1 molecule of Propane has 3 atoms of Carbon and 8 atoms of Hydrogen.

The sample has 3.84 × 10²⁴ H atoms.

If 8 atoms of Hydrogrn are present in 1 molecule of propane.

3.84 × 10²⁴ H atoms are present in

$\mathfrak{ \frac{3.8 }{8} \times 10 ^{24}}$

= 4.75 × 10²³ molecules of Propane.

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

No. of Carbon atoms in 1 molecule of propane = 3

=> C atoms in 4.75× 10²³ molecules of Propane = 3 × 4.75 × 10²³

= 14.25 × 10²³ 

________________________________________

Gram Molecular Mass of Propane(C3H8)

= 3 × 12 + 8 × 1

= 36 + 8

= 44 g

1 mole of propane weighs 44g and has 6.02× 10²³ molecules of Propane.

=> 6.02 × 10²³ molecules of Propane weigh = 44 g

=> 4. 75 × 10²³ molecules of Propane weigh =

$\mathsf{ \frac{44 }{6.02 \times {10}^{23} } \times 4.75 \times {10}^{23} }$

$\mathsf{ = \frac{44 }{6.02 \times \cancel{{10}^{23} }} \times 4.75 \times \cancel{ {10}^{23}} }$

$\mathsf{ = \frac{44 }{6.02 } \times 4.75 }$

= 34.72 g

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2 years ago

What is the net Ionic equation of HClO4(aq)+ NaOH(aq) = H2O(l)+ NaClO4(aq)

uranmaximum [27]

H^+(aq) + OH^-(aq) ---> H2O(l)

Na^+ and ClO4^- are the spectator ions.

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2 years ago

Under identical conditions of temperature and pressure, which of the following gasses is the densest: Ne, CO2, or Cl2?

Tanzania [10]

Cl2=3.17g/L
Ne=.901g/L
CO2=1.96g/l
therefore Cl2 is the densest gas under the given conditions.

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2 years ago