Answer:
0.3811 mol.
Explanation:
- To calculate the no. of moles of a gas, we can use the general law of ideal gas: <em>PV = nRT</em>.
where, P is the pressure of the gas in atm.
V is the volume of the gas in L.
n is the no. of moles of the gas in mol.
R is the general gas constant,
T is the temperature of the gas in K.
∵ P = 2.1 atm, V = 4.5 L, T = 302 K, R = 0.0821 L.atm/mol.K.
<em>∴ n = PV/RT </em>= (2.1 atm)(4.5 L)/(0.0821 L.atm/mol.K)(302.0 K) = <em>0.3811 mol.</em>
Explanation:
Z = atomic mass of the element and , A = atomic mass of the element .
a) Z = 11, A = 23
Element = Sodium
symbol: ²³₁₁Na .
b) Z = 28, A = 64
Element = Nickel
symbol: ⁶⁴₂₈Ni .
c) Z = 50, A = 115
Element = tin
symbol: ¹¹⁵₅₀Sn .
d) Z = 20, A = 42
Element = Calcium
symbol: ⁴²₂₀Ca .
It's 1. Melting a substance. The rest are chemical changes
