Answer:
the Answer is the second one
Explanation:
mole=mass/molar mass
mole=?
molar mass=142.1g/mole
mass=10.0g
The reaction of hydrogen gas (H2) with oxygen gas (O2) is a COMBINATION or SYNTHESIS reaction, because multiple substances combine to form fewer substances. Here, the two gases form one substance, water (H2O):
2H2 + O2 -- > 2H2O
An electrochemical is a type of cell capable of generating electricity from chemical or facilitating chemical reaction through electrical energy
Answer:
NaCl
Explanation:
because He which is helium gas its an element alone,
Cl which is chlorine is a single element,
B which is Boron and its a single element,
but NaCl which is simply called table sugar is the combination between Na, sodium and Cl, chlorine , so its called a compound not an element.