Answer:
discoveries that can change little aspects of our daily lives or finding cures for diseases that have hounded humanity, scientists have been hard at work trying to push us toward a brighter future.
Explanation:
thats what i got from my research :D
<u>Answer:</u> False
<em>Some people believe that the Moon’s phases are caused by Earth’s shadows on the Moon is false.</em>
<u>Explanation:</u>
<em>Some people believe that the Moon’s phases are caused by Earth’s shadows on the Moon is their misconception.
</em>
The phases depend on its place relative with sun and earth.The phases of moon are new moon,waxing crescent, first quarter, waxing gibbon, full moon, wanning gibbon,last quarter, wanning crescent,new moon.
<em>For example,
</em>
When<em> moon, earth, and sun</em> are exactly in the same line and moon lies in between earth and sun, the sun illuminates the back part of the moon which is not visible from earth. <em>This forms new moon</em>.
<em>So only relative positions matter in the phases of moon.
</em>
Answer:
Here's what I get
Explanation:
You have an equilibrium reaction between Fe³⁺/ SCN⁻ and FeSCN²⁺.
When you add AgNO₃, the Ag⁺ reacts with the SCN⁻. It forms a colourless precipitate of Ag(SCN).
Ag⁺(aq) + SCN⁻(aq) ⟶ AcSCN(s)
According to Le Châtelier's Principle, when we apply a stress to a system at equilibrium, the system will respond in a way that tends to relieve the stress.
If you add Ag⁺ to the equilibrium solution, it removes the SCN⁻ [as an Ag(SCN) precipitate].
The system responds by trying to replace the missing SCN⁻:
The Fe(SCN)²⁺ dissociates to form SCN⁻, so the position of equilibrium shifts to the left,
You now have more Fe³⁺ and SCN⁻ and less of the highly coloured Fe(SCN)²⁺ at the new equilibrium.
The deep red colour becomes less intense.
Answer:
Explanation:
Mass of one tablet = 20 mg
Mass of two tablets = 
Percent that is soluble in water = 40%
Mass of tablet that is soluble in water = 
So, mass of solute is 
Density of water = 1 kg/L
Volume of water = 1 L
So, mass of 1 L of water is 
PPM is given by
Hence, the concentration of iodine in the treated water .
Answer:
1.9 × 10² g NaN₃
1.5 g/L
Explanation:
Step 1: Write the balanced decomposition equation
2 NaN₃(s) ⇒ 2 Na(s) + 3 N₂(g)
Step 2: Calculate the moles of N₂ formed
N₂ occupies a 80.0 L bag at 1.3 atm and 27 °C (300 K). We will calculate the moles of N₂ using the ideal gas equation.
P × V = n × R × T
n = P × V / R × T
n = 1.3 atm × 80.0 L / (0.0821 atm.L/mol.K) × 300 K = 4.2 mol
We can also calculate the mass of nitrogen using the molar mass (M) 28.01 g/mol.
4.2 mol × 28.01 g/mol = 1.2 × 10² g
Step 3: Calculate the mass of NaN₃ needed to form 1.2 × 10² g of N₂
The mass ratio of NaN₃ to N₂ is 130.02:84.03.
1.2 × 10² g N₂ × 130.02 g NaN₃/84.03 g N₂ = 1.9 × 10² g NaN₃
Step 4: Calculate the density of N₂
We will use the following expression.
ρ = P × M / R × T
ρ = 1.3 atm × 28.01 g/mol / (0.0821 atm.L/mol.K) × 300 K = 1.5 g/L
