Answer:
0.1472 mol/L is the concentration of the barium hydroxide solution.
Explanation:

Mass of potassium hydrogen phthalate = 2.050 g
Molar mass of potassium hydrogen phthalate = 
According to reaction , 2 moles of potassium hydrogen phthalate reacts with 1 mole of barium hydroxide, then 0.01004 moles of potassium hydrogen phthalate will :
of barium hydroxide
Moles of barium hydroxide = 0.005020 mol
Volume of the barium hydroxide solution = 34.10 mL = 0.03410 L
1 mL = 0.001 L

Molarity of the barium hydroxiude silution :

0.1472 mol/L is the concentration of the barium hydroxide solution.
Answer:
C) 66 calories
Explanation:
The Heat energy required to flow into a unit mass object to raise its temperature by 1 degree is known as specific heat capacity.
specific heat capacity of aluminum, c = 0.22 cal/g°C
mass of aluminium, m = 20.0 g
Hypothesis is your opinion/ your thinking and yes, scientists have hypothesis before they do an experiment
Hope this helps!
Sand and water can be separated by any of the following methods:
1. Sedimentation and decantation: This method involves the mixture being kept undisturbed for some time. After some time, sand being heavier and insoluble in water, settles down at the bottom of container. Now, water is poured into another container to separate it from sand.
2. Filtration: This method involves the mixture being passed through a filter paper (a filter with very fine pores). Sand particles being larger in size are retained by the filter paper and get separated from water.
I hope this helps! :D