Which of the following reactions are exothermic?

 

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

There are many isotopes of uranium and all of them have same atomic number i.e, sum of nmber of neutrons and protons.

In chemistry, a precipitate is an insoluble solid that emerges from a liquid solution. The emergence of the insoluble solid from solution is called precipitation.

Elements that are poor conductors of heat and electricity are called Non metals.

Phencyclidine (PCP) is a drug used for its mind-altering effects. It is also known as Angel dust. As a recreational drug, it is typically smoked, but may be taken by mouth, snorted, or injected. It may also be mixed with cannabis or tobacco.

Causes and Effects ::

* PCP may cause hallucinations, distorted perceptions of sounds, and violent behavior.

* Its effects include seizures, coma, addiction, and an increased risk of suicide.

Vulcanization of rubber is a process of improvement of the rubber elasticity and strength by heating it in the presence of sulfur rubber much stronger, more flexible, and more resistant to heat and other environmental conditions.

A sample of matter must be copper if each atom in the sample has 29 protons.

The substances in which two or more atoms are attached together are called as molecular substances. 

Properties of molecular substances ::

1. Molecular substances are bonded with covalent bonds

2. Bad heat conductivity

3. Bad electrical conductivity

4. Have low melting points.

A nitrogenous base is an element that contains nitrogen that have same chemical properties of the base.