A bond is a force of attraction between atoms. They are mainly fthree types of bonds namely; ionic bond, which involves transfer of electrons between a metal and a non metal, covalent bond which occurs between non metal atoms by sharing of electrons, metallic bond which is a bond in the metal structure between metal atoms and the sea of electrons. in this case carbon and hydrogen are non metals hence they will have a covalent bond between their atoms.
Answer is: coefficient is one.
Chemical reaction: SiO₂ + 4HF → SiF₄ + 2H₂O.
Reaction is balanced when there are equal numbers of elements in both side of the chemical reaction.
HF - hydrofluoric acid, <span>highly corrosive, dissolves many materials.</span>
SiF₄ - silicon tetrafluoride.
Answer:
The expression to calculate the mass of the reactant is 
Explanation:
<em>The amount of heat released is equal to the amount of heat released per gram of reactant times the mass of the reactant.</em> To keep to coherence between units we need to transform 1,080 J to kJ. We do so with proportions:

Then,

Answer:
In a chemical equation, chemicals that react are the reactants, while chemicals that are produced are the products/by products. Both sides of the equation must be balanced.
\
Explanation
When writing a chemical equation, reactants reacts to produce products. For example in the equation for formation of water, hydrogen combines with oxygen as 2H₂ +O₂→2H₂O where the first part before the arrow represent the reactants and the next part after the arrow are the products. Reactants are on the left where as products are on the right.Coefficient 2, in this cases is used for balancing the equation