Answer:
Their answers must be in two decimal places
Answer:
- <em>A compound that conducts an electric current in aqueous solution or in the molten state is</em> a <u>ionic compound</u>.
Explanation:
Some examples of ionic compounds are NaCl, KF, KI, MgSO₄.
Ionic compounds are formed by positivie ions (named cations) and negative ions (named anions). The strong electrostatic atraction between cations and anions permits the formation of crystals, which are stuctures characterized by a regular pattern. In solid state the ions are in fixed positions.
In order to conduct electricity, the charged particles (cations and anions in the case of the ionic compounds) need to move freely.
Hence, since in solid state, ionic compounds do not conduct electric current. But, <em>in molten (liquid) state or in aqueous solution, ionic compounds conduct electric current because, then, the ions move freely.</em>
Answer:
0.0428 M
Explanation:
Because we're asked to calculate the molarity of nickel(II) cation, we need to <u>determine all sources for that species</u>, in this case, all Ni⁺² comes from the nickel(II) bromide solid (NiBr₂).
We use the molecular weight of NiBr₂ to calculate the moles of Ni:
1.87 g NiBr₂ ÷ 218.49g/mol * (1molNi⁺²/1molNiBr₂) = 8.55x10⁻³ mol Ni⁺²
Then we <u>divide the moles by the volume in order to calculate the concentration</u>:
8.55x10⁻³ mol Ni⁺² / 0.200 L = 0.0428 M
Answer:
Explanation:
Molarity is a measure of concentration in moles per liter.
The solution has a molarity of 1.2 M or 1.2 moles per liter. There are 4.0 moles of NaCl, the solute. We don't know the liters of solution, so we can use x.
- molarity= 1.2 mol/L
- moles of solute= 4.0 mol
- liters of solution =x
Substitute the values into the formula.
Since we are solving for x, we must isolate the variable. Begin by cross multiply (multiply the 1st numerator and 2nd denominator, then the 1st denominator and 2nd numerator.
x is being multiplied by 1.2 moles per liter. The inverse of multiplication is division, so divide both sides by 1.2 mol/L
The units of moles (mol) will cancel.
The original measurements both have 2 significant figures, so our answer must have the same. For the number we found, this is the tenths place.
The 3 in the hundredth place tells us to leave the 3 in the tenths place.
Approximately <u>3.3 liters of solution</u> are needed to make a 1.2 M solution with 4.0 moles of sodium chloride.
Answer:
-145.2kJ
Explanation:
Enthalpy is an extensive property as its value depends on the amount of substance present in the system.
If the enthalpy for one mole of methanol = -726 kJ/mol;
The Enthalpy for 0.2 mol is given as;
Enthalpy = 0.200 * 726
Enthalpy = -145.2kJ
It would take -145.2kJ for 0.200 mol of methanol to undego the combustion reaction.