The frequencies expressed in inverse seconds are 5 s⁻¹  and 1 s⁻¹.
<h3>
What is frequency?</h3>
Frequency is the number of complete cycles in a second made by a wave.
F = 1/T
F = n/t
<h3>When n = 5</h3>
F = 5/s =  5 s⁻¹ = 5Hz
<h3>When n = 1</h3>
F = 1/s =  1 s⁻¹ = 1Hz
Learn more about frequency here: brainly.com/question/254161
#SPJ1
 
        
             
        
        
        
Answer:When a substance undergoes a chemical change some of the chemical changes can be reversed with a chemical change.
Explanation:
A chemical change changes all of the element but some chemical changes but very few can be changed back to its original substance only with a chemical change.
 
        
                    
             
        
        
        
Answer: Magnesium Mg
Explanation:
Oxidization is the process by which a substance either gains oxygen or losses electrons. 
The chemical reaction of the above is denoted by,
Mg(s) + 2HCl(aq) -----> MgCl2(aq) + H2(g)
Mg went from a 0 to a +2 state which would mean that it lost electrons. 
It was therefore oxidized. 
Please do react or comment if you need clarification or if the answer helped you. This can help other users as well. Thank you. 
 
        
             
        
        
        
Answer: Option (b) is the correct answer.
Explanation:
A covalent compound is defined as the compound in which sharing of electrons take place between the combining atoms. Generally, when two or more non-metals chemically combine together the it will lead to the formation of a covalent compound.
For example, 
 and HCl is also a covalent compound. 
And, a compound in which transfer of electrons occur between the combining atoms is known as an ionic compound. Whenever, a metal chemically combines with a non-metal then it will always lead to the formation of an ionic compound.
For example, KI is an ionic compound.
Thus, we can conclude that 
 and HCl are the two substances which are covalent compounds.
 
        
             
        
        
        
Balanced equation : C. CH₄ + 4Cl₂⇒  CCl₄+ 4HCl 
<h3>Further explanation  </h3>
Equalization of chemical reactions can be done using variables. Steps in equalizing the reaction equation:  
1. gives a coefficient on substances involved in the equation of reaction such as a, b, or c, etc.  
2. make an equation based on the similarity of the number of atoms where the number of atoms = coefficient × index (subscript) between reactant and product  
3. Select the coefficient of the substance with the most complex chemical formula equal to 1  
Reaction
CH₄ + Cl₂⇒  CCl₄+ HCl 
aCH₄ + bCl₂⇒  CCl₄+ cHCl 
C, left=a, right=1⇒a=1
H, left=4a, right=c⇒4a=c⇒4.1=c⇒c=4
Cl, left=2b, right=4+c⇒2b=4+c⇒2b=4+4⇒2b=8⇒b=4
The equation becomes :
CH₄ + 4Cl₂⇒  CCl₄+ 4HCl