Which of the following reactions are exothermic?

 

$$\begin{gathered} 1) C + O2 → CO2 \\ 2) 2Mg + O2 → 2MgO \\ 3) CuSO4 + 5H2O → CuSO4.5H2O \\ 4) All the above \end{gathered}$$

Cellular respiration is the three-step process by which cells make ATP using glucose and oxygen.

Oxygen and glucose are both reactants in the process of cellular respiration. The main product of cellular respiration is ATP, waste products include carbon dioxide and water.

The gram formula mass of a compound is nothing but the molar mass.

The molar mass of K2CO3 (Potassium Carbonate) is given by

Atomic weights of individual elements are

K (Potassium) = 39 g

C (Carbon) = 12 g

O (Oxygen) = 16 g

Hence, that of K2CO3 = 39(2) + 12 + 16(3)

= 78 + 12 + 48

= 138.

In chemistry, the term transition metal has three possible meanings: The IUPAC definition defines a transition metal as "an element whose atom has a partially filled d sub-shell, or which can give rise to cations with an incomplete d sub-shell".

Any of the set of metallic elements occupying a central block (Groups IVB–VIII, IB, and IIB, or 4–12) in the periodic table, e.g. iron, manganese, chromium, and copper. Chemically they show variable valency and a strong tendency to form coordination compounds, and many of their compounds are coloured.

Here in the given options, only iron (Fe) is a transition metal since Strontium is an alkaline earth, arsenic is a metalloid, hydrogen is (normally) a diatomic gas.

Here I give you the first 30 Atomic elements names and their Atomic masses.

Atomic number      Element        Atomic mass
                             

        1                 Hydrogen           1

        2                  Helium              4

        3                 Lithium              6.94

        4                Beryllium            9.01

        5                  Boron               10.81

        6                Carbon               12.01

        7                Nitrogen             14.01

        8                Oxygen              15.99

        9                Fluorine              19.00

       10                Neon                 20.18

       11               Sodium               22.99

       12             Magnesium           25.31

       13             Aluminium            26.98

       14               Silicon                28.09

       15             Phosphorus           30.97

       16               Sulphur               32.07

       17               Chlorine              35.45

       18                Argon                 39.95

       19             Potassium              39.10

       20              Calcium                40.08

       21             Scandium              44.96

       22             Titanium               47.87

       23            Vanadium              50.94

       24             Chromium            24. 52

       25            Manganese            54.94

       26                Iron                  55.85

       27              Cobalt                 58.93

       28               Nickel                 58.69

       29              Copper                 63.55

       30                Zinc                   65.41

Rust forms when oxygen reacts with chemicals in rocks, and that is often the case with many other elements in general. Like a copper nail being exposed to the air will rust.

Electronegativity is the tendency for an atom to attract electrons. There are general trends on the periodic table which you can use to determine the relative electronegativity for different elements, but otherwise you can also look at their valence shell and effective nuclear charge to determine their relative electronegativity.

Here from the given options, Lithium has least tendency to attract electrons and thus has a lower electronegativity.

Sucrose is not a monosaccharide.

Monosaccharides are simple carbohydrates molecules that cannot be broken down into smaller molecules of other carbohydrates.

Glucose, galactose and fructose are examples of Monosaccharides.

An ionic bond is a chemical bond between two atoms in which one atom seems to donate its electron to another atom.

Here in the given compounds, the compound that contains ionic bond is CaO, Calcium oxide.