The reaction for the formation of MgO(s):
2 Mg (s) + O2(g) -à
2MgO(s) ΔH = -601.24
kJ/mol
<span>The enthalpy
information is taken from: http://webbook.nist.gov/cgi/inchi?ID=C1309484&Mask=2</span>
From the equation and with an enthalpy change of -231 kJ:
-231 kJ * 2 mol Mg * (1/-601.24 kJ/mol) = 0.76841 mol Mg
Then, with the molar mass of MgO = 40.3,
0.76841 mol Mg *(2 mol MgO/2 mol Mg)* 40.3 g/mol MgO = <span>30.967 g MgO</span>
When electrons are removed from the outermost shell of calcium atom, its atom becomes positively charged, with a charge of plus one.
When an electron is added to an atom, the atom becomes negatively charged, with a charge of minus one.
When these atoms become positively or negatively charged, they are known as ions. Positively charged ions are called cations and negatively charged ions are called anions.
Calcium is identified as one of the cations because it is positively charged when its electrons are removed from its outermost shell.
B.
about the same as for humans
Explanation:
This is why most bacteria, during research in labs, are incubated at 37 degrees centigrade, about the same as human body temperature. In addition, harmful and beneficial bacteria thrive in the human body due to the favorable temperatures for growth and reproduction. To try and fight an infection, the body also tries to raise the body temperatures above the optimal for the bacteria growth (the reason one has a fever in case of infection).
Answer:
Explanation:
The definition of acids and bases by Arrhenius Theory was modified and extended by Bronsted-Lowry.
Bronsted-Lowry defined acid as a molecule or ion which donates a proton while a base is a molecule or ions that accepts the proton. This definition can be extended to include acid -base titrations in non-aqueous solutions.
In this theory, the reaction of an acid with a base constitutes a transfer of a proton from the acid to the base.
From the given information:

From above:
We will see that HCN releases an H⁺ ion, thus it is a Bronsted-Lowry acid
accepts the H⁺ ion ,thus it is a Bronsted-Lowry base.
The formula of the reactant that acts as a proton donor is <u>HCN</u>
The formula of the reactant that acts as a proton acceptor is <u>H2O</u>
I believe the answer is C. The bonds in the compound magnesium sulfate is ionic and covalent. Magnesium sulfate is soluble in water. When the said compound is dissolved in water, it dissociates into magnesium ions and sulfate ions. However, the bonds that held together the sulfate ions is covalent.