atoms are made of 3 types of sub atomic particles- protons, neutrons and electrons
from these 3 particles, electrons are responsible for participating in chemical bonds. therefore chemical properties of elements are based on the number of electrons present.
valence electrons are the number of electrons in the outermost energy shell that are involved in chemical bonds.
atoms with same number of valence electrons are grouped in to columns called groups.
therefore elements of the same group have same number of valence electrons, hence similar chemical properties.
from the options given
only Be and Mg belong to the same group they both belong to group 2 with 2 valence electrons
therefore Be and Mg have similar chemical properties
answer is
1) Be and Mg
First you need to find out the Limiting reactant (LR). convert both reactants to the same thing. Check that the chemical equation is balanced. Now use stoichiometr and remember at moles, multiply: need moles, divide2 g / 42g/mol= 0.0477 mol propane mass propane/ Molar Mass propane = moles propane4 g / 32 g/mol= 0.125 mol oxygen X (1 mol/ 5 mol) = 0.025 mol propane oxygen is the LRmass O2 / MM O2 X (mol propane / mol O2)0.025 mol X (3 mol / 1 mol ) = .075 mol CO20.075 mol X (12 + 2*16) g /mol = 3.6 g CO2 In one step:2 g / 42g/mol X (3 mol / 1 mol ) X 48 g/mol = 6.86 g CO24 g / 32 g/mol X (3 mol / 5 mol ) X 48 g/mol = 3.6 g CO2mass/ MM X coefficient ratio X MM (new)
a. 301 cg
b. 6.2 km
Explanation:
a. knowing that 1 gram (g) is equal to 100 centigrams (cg) we devise the following reasoning:
if 1 g is equal to 100 cg
then 3.01 g are equal to X cg
X = (3.01 × 100) / 1 = 301 cg
b. knowing that 1 kilometer (km) is equal to 1000 meters (m) we devise the following reasoning:
if 1 km is equal to 1000 m
then Y km are equal to 6200 m
Y = (6200 × 1) / 1000 = 6.2 km
Learn more about:
converting units of measurement
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<u>Answers:</u>
a. 131.85 grams
b. 134.69 grams
To calculate the number of grams in the number of moles given for each compound, consider the formula:
<em>Moles = No. of grams / molar mass</em>
Therefore, to find the gram it will become:
<em>No. of grams = moles x molar mass</em>
a. 0.410 mol of NaCl (sodium chloride)
Molar mass of NaCl = (286.14 + 35.45) = 321.59
No. of grams = moles x molar mass
No. of grams = 0.410 x 321.59 = 131.85 grams
b. 4.80 mol of C2H4 (ethylene)
Molar mass of C2H4 = (12.01 x 2) + (1.01 x 4) = 28.06
No. of grams = moles x molar mass
No. of grams = 4.80 x 28.06 = 134.69 grams
n=20 mol
(NH)4 SO4
Atomic masses :
N- 14
H- 1
S- 32
O- 16
Therefore M= 14×2 + 1×8 + 32 + 16×4
= 132
m= nM
= 20×132
= 2640g
