Answer:
Magnetic fields, revolve, asteroids
Answer:
Explanation:
Na react with H2O to form NAOH
2 Na+2H2O....................2NAOH + H2
Ca react with water and form calcium hydroxide
Ca + 2H2O........................Ca(OH)2
Mg react with water and form Magnesium hydroxide
Mg +2H2O .........................Mg(OH)2 however this coating of mg(oh)2 prevent it from further reaction
Fe react with water and form ferric hydride
3Fe +H2O.......................2 FeH +FeO
copper do not react with water
Answer:
The correct answer is Pu, 234.
Explanation:
In the given case, let us consider the reactant as X. Now the mass number (balanced) on both the sides will be,
Mass of X = Mass of Molybdenum + Mass of Tin + Mass of neutrons
M = 1 * 103 + 1 * 131 + 2 * 0
M = 234
Now the atomic number (balanced) on both the sides,
Atomic number of X = Atomic number of Molybdenum + Atomic number of Tin + Atomic number of neutrons
A = 1*42 + 1*50 + 2*1
A = 94
The atomic number 94 is for the element Plutonium, whose symbol is Pu. Thus, the reactant is 234-Pu.
Na3PO4*12H2O + BaCl2*2H2O = Ba3(PO4)2 + NaCl + H2O
add barium chloride to your Na3PO4.12H2O a white precipitate of Ba3(PO4)2 will be formed wrt salt(NaCl) and water(H20) if Na3PO4.12H2O. will be there.
The idea here is that you need to figure out how many moles of magnesium chloride,
MgCl
2
, you need to have in the target solution, then use this value to determine what volume of the stock solution would contain this many moles.
As you know, molarity is defined as the number of moles of solute, which in your case is magnesium chloride, divided by liters of solution.
c
=
n
V
So, how many moles of magnesium chloride must be present in the target solution?
c
=
n
V
⇒
n
=
c
⋅
V
n
=
0.158 M
⋅
250.0
⋅
10
−
3
L
=
0.0395 moles MgCl
2
Now determine what volume of the target solution would contain this many moles of magnesium chloride
c
=
n
V
⇒
V
=
n
c
V
=
0.0395
moles
3.15
moles
L
=
0.01254 L
Rounded to three sig figs and expressed in mililiters, the volume will be
V
=
12.5 mL
So, to prepare your target solution, use a
12.5-mL
sample of the stock solution and add enough water to make the volume of the total solution equal to
250.0 mL
.
This is equivalent to diluting the
12.5-mL
sample of the stock solution by a dilution factor of
20
.
