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2 years ago

Iron and aluminim are examples of _________. a. pure substances b. compounds

Chemistry

2 answers:

Ierofanga [76]2 years ago

8 0

Answer:

compounds

Explanation:

Sindrei [870]2 years ago

8 0

A. Pure substances

Iron aluminum, silver, and gold are all examples of a pure substance. Substances that are free from any kind of mixture and contain only one kind of particle are pure substances.

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one reaction that produces hydrogen gas can be represented by the unbalanced chemical equation Mg(s)+HCI(aq) -> MgCI(aq)+H2(g

Sonbull [250]

<h3>Answer:</h3>

128 g HCl

<h3>General Formulas and Concepts:</h3>

Math

Pre-Algebra

Order of Operations: BPEMDAS

Brackets
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction

Left to Right

Chemistry

Atomic Structure

Reading a Periodic Table

Stoichiometry

Reaction Mole Ratios
Using Dimensional Analysis

<h3>Explanation:</h3>

Step 1: Define

[RxN - Unbalanced] Mg (s) + HCl (aq) → MgCl (aq) + H₂ (g)

↓

[RxN - Balanced] 2Mg (s) + 2HCl (aq) → 2MgCl (aq) + H₂ (g)

[Given] 3.25 mol Mg

[Solve] x g HCl

Step 2: Identify Conversions

[RxN] 2 mol Mg → 2 mol HCl

[PT] Molar Mass of H - 1.01 g/mol

[PT] Molar Mass of Cl - 35.45 g/mol

Molar Mass of HCl - 1.01 + 35.45 = 36.46 g/mol

Step 3: Stoich

[S - DA] Set up: $\displaystyle 3.25 \ mol \ Mg(\frac{2 \ mol \ HCl}{2 \ mol \ Mg})(\frac{36.46 \ g \ HCl}{1 \ mol \ HCl})$
[S - DA] Multiply/Divide [Cancel out units]: $\displaystyle 127.61 \ g \ HCl$

Step 4: Check

Follow sig fig rules and round. We are given 3 sig figs.

127.61 g HCl ≈ 128 g HCl

3 0

2 years ago

How many moles are in 24.75 g of H2O? What is given the conversation and the unknown?

riadik2000 [5.3K]

Answer:

1.373 mol H₂O

General Formulas and Concepts:

Chemistry - Atomic Structure

Reading a Periodic Table
Using Dimensional Analysis

Explanation:

Step 1: Define

24.75 g H₂O

Step 2: Identify Conversions

Molar Mass of H - 1.01 g/mol

Molar Mass of O - 16.00 g/mol

Molar Mass of H₂O - 2(1.01) + 16.00 = 18.02 g/mol

Step 3: Convert

$24.75 \ g \ H_2O(\frac{1 \ mol \ H_2O}{18.02 \ g \ H_2O} )$ = 1.37347 mol H₂O

Step 4: Check

We are given 4 sig figs. Follow sig fig rules and round.

1.37347 mol H₂O ≈ 1.373 mol H₂O

7 0

2 years ago

An atom has atomic number of 34. how many protons and electrons does it have? what is its symbol? 34 protons and electrons. se l

AURORKA [14]

Se: Selenium

Protons: 34
Electrons: All atoms in the periodic table are neutral until changed otherwise
Neutrons: 44
Atomic Mass: 78.09

>Symbol attached<

4 0

2 years ago

Using the systematic approach for equilibrium problems, calculate the pH of 0.05 M HOCl. Ka= 3.0*10-8 Group of answer choices 3.

SVEN [57.7K]

Answer:

The pH is equal to 4.41

Explanation:

Since HClO is a weak acid, its dissociation in aqueous medium is:

HClO ⇄ ClO- + H+

start: 0.05 0 0

change -x +x +x

balance 0.05-x x x

As it is a weak acid it dissociates very little, in its ClO- and H + ions, so the change is negative, where x is a degree of dissociation.

the acidity constant when equilibrium is reached is equal to:

$Ka=\frac{[ClO-]*[H+]}{[HClO]}=\frac{x*x}{0.05-x}=3x10^{-8}$

The 0.05-x fraction can be approximated to 0.05, because the ionized fraction (x) is very small, therefore we have:

$3x10^{-8}=\frac{x^{2} }{0.05}$

clearing the x and calculating its value we have:

$x=3.87x10^{-5}=[H+]=[ClO-]$

the pH can be calculated by:

$pH=-log[H+]=-log[3.87x10^{-5}]=4.41$

7 0

3 years ago

statement 1,mass is conserved durning the reaction. statement 2 sum of mass and energy is conserved durning the reaction. which

maksim [4K]

Answer:

Explanation:

None of the statement is true for both chemical and nuclear reactions. In chemical reactions, mass is always conserved and the type of atoms are also conserved.

6 0

2 years ago