Answer:
Explanation:
These instrument works on the analysis of the emisson spectral of light received from the star in this way.
Think of a steel knife in your kitchen. Initially, it has this shiny silver colour that typifies it. When the knife is placed on a hot plate, it becomes hotter and begins to go red as the heating continues. If we stop the heating and pour cold water on it, the red dissapears and our knife is back to itself, although the silvery shine would be lost. This is simply how the atomic absorption spectroscopy works. When you see the hot knife you can say a couple of things about it. Different metals have their various melting point. We can compare the temperature at which our knife will melt with a standard melting point scale to know the type of metal it is made of.
In atomic absorption spectroscopy, an atom gains energy and it becomes excited. Every atom is known to have a peculair amount of absorbant energy that cause them to excite. The more the particles in the atom, the more the energy required. When we analyse the absorbent energy of the atom, it differs from other atoms and we truly identify such an atom even if we don't know it. Most times, the energy is given off as light.
Answer:
MOLAR MASS = 32 g/mol
Explanation:
Condition of standard temperature and pressure(STP) are as follow:
Temperature = 273 K
Pressure = 1 atm (or 100000 Pa)
Here atm is atmosphere and Pa is Pascal
STP conditions arte used for measuring gas density and volume using Ideal Gas Law.Here 1 mole of ideal gas occupies 22.4 L of volume.
According toi Ideal Gas Equation :
PV = nRT
where P = pressure, n= number of moles, V = volume ,R= Ideal Gas Constant and T= temperature
From question:
V=280 ml = 0.28 L
P = 1 atm
R=0.08205 L atm/K mol
T=273 K
Putting values in above formula :
n = 0.0125 moles
Now 
given mass = 0.4 g (given)
On solving we get:
Molar mass = 32 g/mol
Answer:
Explanation:
All the colligatives properties are modified by the Van't Hoff factor. This is shown as i, in the formula of the colligative properties freezing point depression, boiling point elevation, and osmotic pressure.
The Van't Hoff factor shows the number of particles into which the solute dissociates. In organic compounds we use 1, in inorganic compounds we have to think the dissociation. For example in aquous solutions, inorganic salts as AgNO₃ and CaCl₂ dissociate like this:
AgNO₃ → Ag⁺ + NO₃⁻
CaCl₂ → Ca²⁺ + 2Cl⁻
AgNO₃ has 2 moles of ions and CaCl₂ has 3 moles.
In urea: i = 1
In silver nitrate: i = 2
In calcium chloride: i = 3
The i = 3 for calcium chloride, makes that this salt has the highest osmotic pressure, highest vapor pressure and highest boiling point.
Answer:
The heat required to raise the temperature of 12g of water from 16 C to 21 C is 60 cal.
Explanation:
Calorimetry is the measurement and calculation of the amounts of heat exchanged by a body or a system.
There is a direct proportional relationship between heat and temperature. The constant of proportionality depends on the substance that constitutes the body as on its mass, and is the product of the specific heat by the mass of the body. So, the equation that allows calculating heat exchanges is:
Q = c * m * ΔT
where Q is the heat exchanged by a body of mass m, made up of a specific heat substance c and where ΔT is the temperature variation.
In this case, you know:
- Q=?
- c= 4.186
- m= 12 g
- ΔT=Tfinal - Tinitial= 21 °C - 16°C= 5 °C
Replacing:
Q= 4.186 *12 g *5 °C
Solving:
Q=251.16 J
Since 1 J is equal to 0.2388 cal, then the following rule of three can be applied: if 1 J is equal to 0.2388 cal, then 251.16 J to how many cal are?
cal= 59.98 ≅ 60
<u><em>The heat required to raise the temperature of 12g of water from 16 C to 21 C is 60 cal.</em></u>
The
balanced chemical reaction is:<span>
N2 + 3H2 = 2NH3
<span>We are given the amount of the product to be
produced. This will be the starting point of our calculations.
17 mol NH3 ( 1 mol N2 / 2 mol NH3 ) = 8.5 mol N2
Therefore, the required N2 to produce the given amount of ammonia is 8.5 mol.</span></span>
