Answer:
Forensic drug chemists analyze samples of unknown materials including powders, liquids and stains to determine the chemical identity or characteristics of the compounds that make up the sample. samples submitted as evidence in a drug-related case can contain one compound or a mixture of many compounds.
Answer:
Option C. 1
Explanation:
Step 1:
Determination of the Neutron of both isotopes. This is illustrated below.
For isotope y xA:
Mass number = y
Atomic number = x
Neutron =..?
Atomic number = proton number = x
Mass number = Proton + Neutron
y = x + Neutron
Rearrange
Neutron = y – x
For isotope (y + 1) xA:
Mass number = y + 1
Atomic number = x
Neutron =.?
Atomic number = proton number = x
Mass number = Proton + Neutron
y + 1 = x + Neutron
Rearrange
Neutron = y + 1 – x
Step 2:
Determination of the difference between the neutron number of both isotopes. This is illustrated below:
For isotope y xA:
Neutron number = y – x
For isotope (y + 1) xA:
Neutron number = y + 1 – x
Difference in neutron number
=> (y + 1 – x) – (y – x)
=> y + 1 – x – y + x
Rearrange
=> y – y + 1 – x + x
=> 1
Therefore, the difference in the neutron number of both isotopes is 1
Q: What is the change of entropy for 3.0 kg of water when the 3.0 kg of water is changed to ice at 0 °C? (Lf = 3.34 x 105 J/kg)
Answer:
-3670.33 J/K
Explanation:
Entropy: This can be defined as the degree of randomness or disorderliness of a substance. The S.I unit of Entropy is J/K.
Mathematically, change of Entropy can be expressed as,
ΔS = ΔH/T ....................................... Equation 1
Where ΔS = Change of entropy, ΔH = heat change, T = temperature.
ΔH = -(Lf×m).................................... Equation 2
Note: ΔH is negative because heat is lost.
Where Lf = latent heat of ice = 3.34×10⁵ J/kg, m = 3.0 kg, m = mass of water = 3.0 kg
Substitute into equation
ΔH = -(3.34×10⁵×3.0)
ΔH = - 1002000 J.
But T = 0 °C = (0+273) K = 273 K.
Substitute into equation 1
ΔS = -1002000/273
ΔS = -3670.33 J/K
Note: The negative value of ΔS shows that the entropy of water decreases when it is changed to ice at 0 °C
The mass of magnesium, which has a density of 1.74 g/cm is 504.6 g.
<h3>What is mass?</h3>
Mass is the quantity of matter. Mass can be calculated by multiplying density by volume.
Magnesium is a chemical element with the atomic number 12. It is needed in the body in trace amounts. It can cause malnutrition in the body.
Mass = Density x volume
We know the density and the volume of magnesium.
Density = 1.74
Volume = 290
Density x volume
Putting the value in the equation
1.74 x 290 = 504.6 g
Thus, the mass of magnesium is 504.6 g.
To learn more about mass, refer to the below link:
brainly.com/question/22795877
#SPJ1
In easy words the connection between Reactants, Products and Limiting reactants is as follow,
Reactants and Products:
Reactants are the starting materials for the synthesis of final synthesized materials called as products.
Example:
CH₄ + 2 O₂ → CO₂ + 2 H₂O
In above reaction Methane (CH₄) and Oxygen (O₂) are the reactants while, CO₂ and H₂O are the products.
Reactants, Products and Limiting Reactants:
Considering the same example it is seen that for one mole of CO₂ two moles of O₂ are required to completely convert into CO₂ and H₂O. If either of the reactant is taken less than the required amount then it will act as a limiting reactant because it will consume first leaving the second reactant present in excess as compare to it. Hence, we can say that the limiting reactant is the starting material which controls the amount of product being formed.
