Atoms are made of 3 types of subatomic particles ; protons, neutrons and electrons
protons and neutrons are located inside the nucleus and electrons are found in energy shells around the nucleus. Protons are positively charged, electrons are negatively charged and neutrons are neutral. elements in their ground state are neutral with equal amounts of protons and electrons.
Atomic number is the number of protons. atomic number is characteristic for the element.
atomic number of Be is 4 therefore Be has 4 protons
answer is B. 4
The conversion factor for volume at STP is
or
. Since we want volume, we would use
. We conclude with the following calculations:
The answer is 9.744L H2
<span>1. </span>Heat
gained in a system can be calculated by multiplying the given mass to the
specific heat capacity of the substance and the temperature difference. It is
expressed as follows:<span>
Heat = mC(T2-T1)
Heat = 100(4.184)(20 - 16)
<span>Heat = 1673.6 J</span></span>
Answer:
236.9g
Explanation:
Given parameters:
Volume of gas = 81.3L
Pressure of gas = 204kPa
temperature of gas = 95°C
Unknown:
Mass of carbondioxide gas = ?
Solution:
To solve this problem, the ideal gas law will be well suited. The ideal gas law is a fusion of Boyle's law, Charles's law and Avogadro's law.
Mathematically, it is expressed as;
PV = nRT
the unknown here is n which is the number of moles;
P is the pressure, V is the volume, R is the gas constant and T is the temperature.
convert pressure into atm
101.325KPa = 1atm
204 kPa = 
= 2atm
Convert temperature to Kelvin; 95 + 273 = 368K
2 x 81.3 = n x 0.082 x 368
n = 
= 5.38moles
Since the unknown is mass;
Mass = number of moles x molar mass
Molar mass of carbon dioxide = 12 + 2(16) = 44g/mol
Mass = 5.38 x 44 = 236.9g
Answer:
a. 2257.7 kW b. 6.057kw/K
Explanation:
Steam existing at 100KPa with t = 20C, we can obtain values of enthalpy and entropy from table
h1 = hf = 417.4 kJ/kg
s1 = 1.302 KJ/kg.K
h2 = hg = 2675.1 kJ/kg
s2 = 7.359 kJ/K
a. Electrical Power consumption of system is given by Wel = mass x Change in Enthalpy
Wel = 1 x (h2 - h1) = 1 x (2675.1 - 417.4) = 2257.7 kw
b . Entropy Generation is given by Change in Entropy = Entropy generation - heat dissipated/temperature, since we have a well insulated system with no losses, q =0, hence
ΔS = Sgen + 0/T = Sgen
m(S2 - S1) = Sgen
Sgen = 1 x (7.359 - 1.302) = 6.057 kW/K
