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morpeh [17]
3 years ago
14

Help meee pleaseeeee

Chemistry
1 answer:
tatiyna3 years ago
7 0

Answer:

see explanation

Explanation:

Using the periodic table, look at the top of each column => These are group numbers ... Typically (for american tables) the numbers are divided into A-Groups and B-Groups... For this post, you need to focus on the A-Groups, or 'Main Group Elements'... Now, the numbers also represent the number of valence (outer shell) electrons in the elements listed below that number. For example, under Group IA, all elements ( H, Li, Na, K, Rb, Cs & F) all have one (1) outer shell electron. All elements under IIA have two outer shell electrons, IIIA, 3 outer shell electrons and so on. The exception is Helium (He) which has only 2 outer shell electrons and is typically listed under Group VIIIA.

So ...

X· => H, Li & Na

X: => He(noble gas exception), Be & Mg

·X: => B & Al

:X: => C & Si

X(5 dots) => N  

X(6 dots) => O

X(7 dots) => F & I

X(8 dots) => Ne

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If 45.8 grams of potassium chlorate decomposes, how many grams of oxygen gas can be produced? 2KClO3 → 2KCl + 3O2
natta225 [31]
To do this problem, we must first look at the balanced chemical equation for the decomposition of potassium chlorate: 

<span>2KClO3 --> 2KCl + 3O2 </span>

<span>We can take the given amount of grams, and use the molar mass of KClO3 to convert to moles. Then, we can use the stoichiometric ratios to relate moles of KClO3 to moles of O2. </span>

<span>(39.09)+(35.45)+(3*15.99)= 122.51 g/ mol = molar mass of KClO3 </span>
<span>45.8 g KClO3/ 122.51 g/ mol KClO3 = .374 moles KClO3 </span>
<span>.374 mol KClO3 *(3 moles O2/2 mol KClO3)= .560 moles O2 </span>

<span>Once we have moles of O2, we can convert to grams of O2. </span>

<span>(2*15.99)= 31.98 g/mol = molar mass of O2 </span>
<span>(.560 moles O2) (31.98 g/mol)= 17.91 g O2 </span>


<span>Hope this helps :)</span>
3 0
3 years ago
Mehtyl alcohol is called wood spirit. Its molecular formula is CH3OH. Calculate the number of moles that would contain 2.5*10^21
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The 2.5 x 10²¹ molecules of CH₃OH have 0.00415 moles.

<h3>What is the mole concept?</h3>
  • The Mole concept is used to express the amount of substance conveniently.
  • A mole is defined as the amount of substance that contains exactly 6.022 x 10²³ elementary particles of the given substance. Here, elementary particles refer to atoms, molecules, or ions.
  • This fixed number  6.022 x 10²³ is known as Avogadro Number and is denoted by N_A
<h3>How to calculate the number of moles?</h3>

The number of moles is given by

n=\frac{m}{M}

When given mass = molar mass of a substance, then no of moles is equal to 1 which is equivalent to 6.022 x 10²³.

We also know,

1 mole has 6.022 x 10²³ molecules of CH₃OH

According to the mole concept,

6.022 x 10²³ molecules of CH₃OH is equal to 1 mole

2.5 x 10²¹molecules of CH₃OH is equal to \frac{2.5\times10^2^1}{6.022 \times 10^2^3} moles

Thus, 2.5 x 10²¹molecules of CH₃OH are equal to 4.15 x 10⁻³ moles or 0.00415 moles

Learn more about the mole concept:

brainly.com/question/1427235

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I am so sorry if I am wrong but my guess is no precipitate is formed.

Explanation:

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Follow safety measures and safety rules to avoid any accident.

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2. Safety rules should always be followed when conducting an experiment at any place such as at home, class room and laboratory etc in order to avoid any accident.

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