The concentration of the solution is 4.25 M
Explanation
molarity=moles/volume in liters
moles = mass/molar mass
molar mass of HF = 19 + 1 = 20 g/mol
moles is therefore = 17.0 g/ 20 g/mol = 0.85 moles
volume in liters = 2 x10^2ml/1000 = 0.2 liters
therefore molarity = 0.85/0.2 = 4.25 M
Answer:
339.2K
Explanation:
Using Charles law equation;
V1/T1 = V2/T2
Where;
V1 = initial volume (L)
V2 = final volume (L)
T1 = initial temperature (K)
T2 = final temperature (K)
According to the information provided in this question,
V1 = 2.97 L
V2 = 3.42 L
T1 = 21.6°C = 21.6 + 273 = 294.6K
T2 = ?
Using V1/T1 = V2/T2
2.97/294.6 = 3.42/T2
Cross multiply
2.97 × T2 = 294.6 × 3.42
2.97T2 = 1007.532
T2 = 1007.532 ÷ 2.97
T2 = 339.236
The final temperature is 339.2K
Answer 1:
Correct Answer: Option A i.e. <span>The temperature stays constant for a while, then rises (A).
Reason:
At 0 oC, H2O exist in dual state (solid and liquid) i.e. there exist an equilibrium between ice and water. Hence, when the heat is supplied, it is initially used to bring about phase transformation from solid to liquid state. During this time, temperature remains constant. Once the phase transformation has occurred, heat is utilized for increasing the temperature of system i.e. water.
.......................................................................................................................
Answer 2:
Correct Answer: Option </span><span>B) At first, the energy supplied goes into overcoming attractive forces in the solid. </span><span>
Reason:
In the present case, initially</span> the energy supplied goes into overcoming attractive forces in the solid. Once the ice is converted into water, it now exist in single phase i.e .liquid. Hence, now when further heat is supplied to the system, it is used only for increasing the temperature of system.
Iodine (iodine-potassium iodide) staining distinguishes starch ( a polysaccharide) from monosaccharides, a disaccharides and other polysaccharides. Therefore, a bluish black color is a positive test for starch, and a yellow-ish brown color ( no color change) is a negative test for starch.
