Covalent bond is a type of chemical bond which is formed as a result of sharing of electron pairs among the elements that are involved. The structure of the covalent bond is affected by the electronegativity of the elements involved. The molecules joined by covalent bond range in size from very small to very large polymers. There are different types of structures for covalent substances, these include: macromolecular substances, molecular substances and giant covalent structures. Strong bonds hold individual molecules together but there are negligible forces of attraction among them.
Answer is: variables that were manipulated during the experiment.
The two main variables in an experiment are the independent and dependent variable.
Dependent variable is the variable being tested and measured in a scientific experiment.
Dependent variables depend on the values of independent variables. The dependent variables represent the output or outcome whose variation is being studied.
Laboratory room number is the least important.
Answer:
Final temperature = 
Explanation:
Given that,
Heat added, Q = 250 J
Mass, m = 30 g
Initial temperature, T₁ = 22°C
The Specific heat of Cu= 0.387 J/g °C
We know that, heat added due to the change in temperature is given by :

Put all the values,

So, the final temperature is equal to
.
Answer:
Ethylene diamine will bond to the Central metal via a lone pairs of electrons on nitrogen
Explanation:
Complexes are formed by coordinate bond formation. Before a coordinate bond is formed, one of the species must have a lone lair of electrons available for donation into empty orbitals on the central metal.
Ethylene diammine contains nitrogen which has a lone pair of electrons. The two lone pairs on the two nitrogen atoms can bond with the central metal. This makes ethylene diammine a bidentate ligand (two bonding atoms).