Answer: 72 grams of  are needed to completely burn 19.7 g
 are needed to completely burn 19.7 g 
Explanation:
According to avogadro's law, 1 mole of every substance weighs equal to molecular mass and contains avogadro's number  of particles.
 of particles.
To calculate the number of moles, we use the equation:

Putting in the values we get:


According to stoichiometry:
1 mole of  requires 5 moles of oxygen
 requires 5 moles of oxygen
0.45 moles of  require=
 require=  moles of oxygen
 moles of oxygen
Mass of 
72 grams of  are needed to completely burn 19.7 g
 are needed to completely burn 19.7 g 
 
        
             
        
        
        
Answer:  -Ionic bonds form when one atom provides electrons to another atom. Covalent Bonds: Covalent bonds form when two atom shares their valence electrons. Metallic Bonds: Metallic bonds form when a variable number of atoms share a variable number of electrons in a metal lattice.
-Covalent Bonds.
Covalent Compounds. Contain no metals and no ions. Covalent compounds contain nonmetals only.
Example:
Ionic Compounds. A metal with a non-metal. Doesn't use prefixes for naming. Name the metal and change the nonmetal ending to -ide.
Explanation: Ionic bonds form when a nonmetal and a metal exchange electrons, while covalent bonds form when electrons are shared between two nonmetals. An ionic bond is a type of chemical bond formed through an electrostatic attraction between two oppositely charged ions.
 
        
             
        
        
        
1.4 mg/dL = 0.014 g/L
Explanation:
Milligrams per deciliter to grams per liter 
There is 1000 grams of mg/dL of 1 g/L
 
        
                    
             
        
        
        
Answer:
I think no C or D 
if wrong correct me plsssssss 
Mark me brainliest plsss 
Explanation:
December 21 marks the winter solstice in the Northern Hemisphere, but in 2020 the longest night of the year is also going to be a witness to an incredible astronomic event known as the “great conjunction”. ... This rare double planet sighting–or “Great Conjunction”–can be viewed from anywhere around the globe