Answer:
Explanation:
The period law state that when elements are listed in order of their atomic numbers, the elements fall into recurring groups, so that there is a recurrence of similar properties at regular intervals.
Na and K in the periodic table fall into the same group, this is because they both have one electrons in their outermost shell.
Na 11 -1s2 2s2 2p6 3s1
K 19 - 1s2 2s2 2p6 3s2 3p6 4s1
They share similar chemical and physical properties. Na and K are very reactive metals, they can loose/donate their outermost electron to non metals in other to attain stable octet state.
The form ionic compound when they react with non metals.
Answer:
The minimum rate of fresh air in the room is 176 moles/min
Explanation:
High exposure of CO₂ has health effects as headaches, increased heart rate, elevated blood pressure, coma, asphyxia, convulsions, etc.
0,500 mole% of CO₂ in air means 0,500 moles of CO₂ per 100 moles of air
As the rate of sublimation of CO₂ is 0,880, the minimum rate of fresh air in the room must be:
X = <em>176 moles of Air/min</em>
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I hope it helps!
corrected question: A chemist adds 135mL of a 0.21M zinc nitrate solution to a reaction flask. Calculate the mass in grams of zinc nitrate the chemist has added to the flask. Round your answer to significant digits.
Answer:
5.37g
Explanation:
0.21M means ; 0.21mol/dm³
1dm³=1L , so we can say 0.21mol/L
if 0.21mol of Zinc nitrate is contained in 1L of water
x will be contained in 135mL of water
x= 0.21*135*10³/1
=0.02835moles
number of moles= mass/ molar mass
mass= number of moles *molar mas
molar mass of Zn(NO₃)₂=189.36 g/mol
mass= 0.02835 *189.36
mass=5.37g
To make sure no cracks are in the crucible and also to remove any moisture present in the crucible by the process of heating.
