Answer: (3)
Medeleev arranged elements in order of increasing atomic weight and similar properties
He noticed that similar elements were grouped together by using this.
Answer:
Option (c).
Explanation:
Cellulose is one of the most important carbohydrate of the plant that provide structural framework to the plant cells. Cellulose is made of the monomer of the glucose that are linked through the beta glycosidic linkages.
Although cellulose contains large number of glucose but it cannot be used as the nutrient source for humans. Humans and other vertebrates lacks the enzyme cellulase that is required for the digestion of cellulose. Cellulose cannot be broken down in the human body.
Thus, the correct answer is option (c).
The identity of the metal is copper.
<h3>What is specific heat?</h3>
The amount of energy needed to raise the temperature of one gram of a substance by one degree Celsius.
Using the formula of specific heat
H = mcdT
Where, H = Heat absorbed
m = mass of the metal
c = specific heat capacity of the metal
dT = temperature change
Putting the values in the equation
20 J = 0.0052 Kg × c × ( 40.0°C - 30.0°C)
c = 20 J/0.0052 Kg × ( 40.0°C - 30.0°C)
c = 385 JKg-1°C-1
Thus, the metal is copper.
Learn more about specific heat
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Answer:
Density of unit cell ( rhodium) = 12.279 g/cm³
Explanation:
Given that:
The radius (r) of a rhodium atom = 135 pm
The atomic mass of rhodium = 102.90 amu
For a face-centered cubic unit cell,
where;
a = edge length.
Making "a" the subject of the formula:
a = 381.8 pm
to cm, we get:
a = 381.8 × 10⁻¹⁰ cm
However, recall that:
where;
mass of unit cell = mass of atom × numbers of atoms per unit cell
Also;
Recall also that number of atoms in a unit cell for a face-centered cubic = 4
So;
mass of unit cell = 6.83380375 × 10⁻²² g
Density of unit cell ( rhodium) = 12.279 g/cm³
Answer:
223 g O₂
Explanation:
To find the mass of oxygen gas needed, you need to (1) convert moles Al to moles O₂ (via the mole-to-mole ratio from reaction coefficients) and then (2) convert moles O₂ to grams O₂ (via the molar mass). When writing your ratios/conversions, the desired unit should be in the numerator in order to allow for the cancellation of the previous unit. The final answer should have 3 sig figs because the given value (9.30 moles) has 3 sig figs.
4 Al + 3 O₂ ----> 2 Al₂O₃
^ ^
Molar Mass (O₂): 32.0 g/mol
9.3 moles Al 3 moles O₂ 32.0 g
------------------- x --------------------- x -------------------- = 223 g O₂
4 moles Al 1 mole
