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3 years ago

How many halogens are in the period 3 of the periodic table

2 answers:

8 0

Halogen, any of the six nonmetallic elements that constitute Group 17 (Group VIIa) of the periodic table. The halogen elements are fluorine (F), chlorine (Cl), bromine (Br), iodine (I), astatine (At), and tennessine (Ts).

I hope this helps you.

Natasha_Volkova [10]3 years ago

8 0

Answer: 17

Explanation:

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How might a theory relate to a model

oksian1 [2.3K]

These are related but can be independent, because it is possible to, the theories are studied in mathematical logic, especially in model theory

8 0

4 years ago

Al2(SO4)3(s) + H2O(l) ---- Al2O3(s) + H2SO4 (aq) calculate enthalpy formation for this reaction. Balance the reaction. Calculate

katen-ka-za [31]

The given chemical equation is:

$Al_{2}(SO_{4})_{3}(aq)+H_{2}O(l)-->Al_{2}O_{3}(aq)+H_{2}SO_{4}(aq)$

On balancing the equation we get,

$Al_{2}(SO_{4})_{3}(aq)+3H_{2}O(l)-->Al_{2}O_{3}(aq)+3H_{2}SO_{4}(aq)$

Calculating enthalpy of formation of this reaction from the standard heats of formation of the products and reactants:

Δ $H_{reaction}^{0}=[H_{f}^{0}(Al_{2}O_{3}(s)) + (3*H_{f}^{0}(H_{2}SO_{4}(aq))] - [H_{f}^{0}(Al_{2}SO_{4}(aq)) + (3*H_{f}^{0}(H_{2}O(l))]$

=[(-1669.8kJ/mol)+ {3* (-909.27 kJ/mol)}]-[(-3442kJ/mol)+{3*(-285.8 kJ/mol)}]

=[(-4397.61kJ/mol)]-[(-4299.4kJ/mol)]

=-98.21kJ/mol

Total enthalpy change when 15 mol of $Al_{2}(SO_{4})_{3}$ reacts will be=

$15 mol Al_{2}(SO_{4})_{3}*\frac{-98.21kJ}{1 molAl_{2}(SO_{4})_{3}} =-1473.15kJ/mol$

4 0

3 years ago

If you were asked to convert 4.2 × 1022 atoms of aluminum to moles, which of the following should you use for the conversion?

DanielleElmas [232]

<span><span>4.2×1022</span>NA</span><span> N_{A} is the avagadro number</span>

7 0

3 years ago

An object with a mass of 6.9 g raises the level of water in a graduated cylinder from 25.1 mL to 30.4 mL. What is the density of

Nana76 [90]

Answer:

The answer is

Explanation:

The density of a substance can be found by using the formula

$density = \frac{mass}{volume} \\$

From the question

mass of object = 6.9 g

volume = final volume of water - initial volume of water

volume = 30.4 - 25.1 = 5.3 mL

It's density is

$density = \frac{6.9}{5.3} \\ = 1.30188679...$

We have the final answer as

Hope this helps you

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3 years ago

Please help with one and 2

adoni [48]

Number two is traits

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4 years ago