Answer:
1) When 6.97 grams of sodium(s) react with excess water(l), 56.0 kJ of energy are evolved.
2) When 10.4 grams of carbon monoxide(g) react with excess water(l), 1.04 kJ of energy are absorbed.
Explanation:
1) The following thermochemical equation is for the reaction of sodium(s) with water(l) to form sodium hydroxide(aq) and hydrogen(g).
2 Na(s) + 2H₂O(l) ⇒ 2NaOH(aq) + H₂(g) ΔH = -369 kJ
The enthalpy of the reaction is negative, which means that 369 kJ of energy are evolved per 2 moles of sodium. The energy evolved for 6.97 g of Na (molar mass 22.98 g/mol) is:

2) The following thermochemical equation is for the reaction of carbon monoxide(g) with water(l) to form carbon dioxide(g) and hydrogen(g).
CO(g) + H₂O(l) ⇒ CO₂(g) + H₂(g) ΔH = 2.80 kJ
The enthalpy of the reaction is positive, which means that 2.80 kJ of energy are absorbed per mole of carbon monoxide. The energy evolved for 10.4 g of CO (molar mass 28.01 g/mol) is:

3.21e+11 is your answer for 321 millimeters in picometers. Hope this helps!
<span>C is the correct answer. Elements in the periodic table are grouped based on having similar properties. For example, the noble gases are all non-reactive and non-metallic. The electronic structure of an atom is the way the electrons are arranged within it, and this affects where they are located in the periodic table. The number of electrons in an element is the same as its group number in the periodic table (with the exception of Group 0).</span>
Answer:
Solution - (a) Brine . Suspension - (c) sand and water, (g) chalk and water Colloid - (e) air, (f) smoke , (d) soda , (b) milk
Explanation:
A solution is an homogeneous mixture of two or more compounds.
A suspension is a heterogeneous mixture of two or more compounds while a colloid is a homogeneous mixture of two or more compounds with suspended particles which do not settle.
So, under these definitions, the classifications are as follows-
Solution - (a) Brine .
Suspension - (c) sand and water, (g) chalk and water
Colloid - (e) air, (f) smoke , (d) soda , (b) milk
I believe it's a pure element