Answer:
4.1 mol·L⁻¹
Explanation:
You are diluting the solution with water, so you can use the dilution formula
c₁V₁ = c₂V₂ Divide each side by V₂
c₂ = c₁ × V₁/V₂
Data:
c₁ = 7.0 mol·L⁻¹; V₁ = 2.5 L
Water added = 1.5 L
Calculations:
(a) <em>New volume
</em>
V₂ = 2.5 L + 1.8 L
= 4.3 L
(b) <em>New concentration
</em>
c₂ = 7.0 × 2.5/4.3
= 7.0 × 0.581
= 4.1 mol·L⁻¹
Answer:
Group 7 or the Halogens
Explanation:
The halogens occupies the 7th group on the periodic table. The group is made of F, Cl , Br, I and At.
The elements in this group are the most reactive of all elements. They are very reactive because they have just 7 electrons in their outermost shell and they only require an electron to complete their electronic configuration to produce an octet which typically mimics the stable group VIII elements.
This makes them very highly reactive.
Answer:
222.30 L
Explanation:
We'll begin by calculating the number of mole in 100 g of ammonia (NH₃). This can be obtained as follow:
Mass of NH₃ = 100 g
Molar mass of NH₃ = 14 + (3×1)
= 14 + 3
= 17 g/mol
Mole of NH₃ =?
Mole = mass /molar mass
Mole of NH₃ = 100 / 17
Mole of NH₃ = 5.88 moles
Next, we shall determine the number of mole of Hydrogen needed to produce 5.88 moles of NH₃. This can be obtained as follow:
N₂ + 3H₂ —> 2NH₃
From the balanced equation above,
3 moles of H₂ reacted to produce 2 moles NH₃.
Therefore, Xmol of H₂ is required to p 5.88 moles of NH₃ i.e
Xmol of H₂ = (3 × 5.88)/2
Xmol of H₂ = 8.82 moles
Finally, we shall determine the volume (in litre) of Hydrogen needed to produce 100 g (i.e 5.88 moles) of NH₃. This can be obtained as follow:
Pressure (P) = 95 KPa
Temperature (T) = 15 °C = 15 + 273 = 288 K
Number of mole of H₂ (n) = 8.82 moles
Gas constant (R) = 8.314 KPa.L/Kmol
Volume (V) =?
PV = nRT
95 × V = 8.82 × 8.314 × 288
95 × V = 21118.89024
Divide both side by 95
V = 21118.89024 / 95
V = 222.30 L
Thus the volume of Hydrogen needed for the reaction is 222.30 L
Answer is number 4.
The above diagram shows a part of our solar system.The planet which is very close to the sun is Mercury. Hence, No.1 is Mercury and 2 and 3 are Venus and Earth respectively. Moon is an astronomical body which orbit planet Earth. Hence moon should be shown near to the planet Earth.
Of the following given choices;
A. iron
B. plastic
C. aluminum
D. wood
The answer is; A
Magnetism is the result from the unpaired spins of electrons in the orbital shells of the atoms of an element. Aluminum (though a metal with +3 valency like iron) has it S and P orbitals filled hence most of its electrons are paired. Iron, on the other hand, a transitional metal, has a D orbital that can be filled before the P orbital is filled. Therefore, there is a higher net unpaired spin of electrons giving the atoms net magnetic properties.