Answer:
C.
Explanation:
Metals tends to lose electrons and form positive ions, known as cations. Whereas, non-metals tend to gain electrons and form negative ions known as anions.
Exothermic reactions are chemical reactions that proceed with the release of heat energy. I contrast, endothermic reactions involve absorption of heat.
The enthalpy change (ΔH) for exothermic reactions is negative while that of endothermic reactions is positive.
In the given examples, reactions that show a negative ΔH are:
NH3 + HCl ------- NH4Cl ΔH = -176 KJ/mol
2Mg + O2 -------- 2MgO ΔH = -1203 kj/mol
C + O2 ---- CO2 ΔH = -393.5 kj/mol
CH4 + 2O2 ----------------- CO2 + 2H2O ΔH = -891 kj/mol
Answer:
the answer is 4 because 3 just have d orbitals
The answer is: the mass of 6.02 x 1023 representative particles of the element.
The base SI unit for molar mass is kg/mol, but chemist more use g/mol (gram per mole).
For example, molar mas of ammonia is 17.031 g/mol.
M(NH₃) = Ar(N) + 3 · Ar(H) · g/mol.
M(NH₃) = 14.007 + 3 · 1.008 · g/mol.
M(NH₃) = 17.031 g/mol.
The molar mass (M) is the mass of a given substance (in this example ammonia) divided by the amount of substance.
Answer: 179 of
will be produced.
Explanation:
To calculate the moles :
![\text{Moles of} H_2=\frac{20.0g}{2.01g/mol}=9.95moles](https://tex.z-dn.net/?f=%5Ctext%7BMoles%20of%7D%20H_2%3D%5Cfrac%7B20.0g%7D%7B2.01g%2Fmol%7D%3D9.95moles)
According to stoichiometry :
2 moles of
give = 2 moles of ![H_2O](https://tex.z-dn.net/?f=H_2O)
Thus 9.95 moles of
will require=
of ![H_2O](https://tex.z-dn.net/?f=H_2O)
Mass of ![H_2O=moles\times {\text {Molar mass}}=9.95moles\times 18g/mol=179g](https://tex.z-dn.net/?f=H_2O%3Dmoles%5Ctimes%20%7B%5Ctext%20%7BMolar%20mass%7D%7D%3D9.95moles%5Ctimes%2018g%2Fmol%3D179g)
Thus 179 of
will be produced.