D . Different branches of the government check one another’s powers
Answer:
Amy can apply the Tyndall Beam effect ,by shining a beam of light through the sample solution.
Explanation:
The chemical test for starch is add iodine solution to the tested sample which is yellow/brown and observe the color change to blue/black color. However, the physical test to distinguish simple sugars from starch is the shine a beam of light through the sample solution. Because that sample solution contained no simple sugars, then the presence of starch in the solution will be indicated by dispersal of light because the large starch molecules are enough to affect the light.
Complete Question:
A chemist adds 55.0 mL of a 1.1M barium acetate (Ba(C2H3O2)2) solution to a reaction flask. Calculate the mass in grams of barium acetate the chemist has added to the flask. Round your answer to 2 significant digits.
Answer:
15 g
Explanation:
The concentration of the barium acetate is given in mol/L (M), thus, the number of moles (n) of it is the concentrantion multiplied by the volume (55.0 mL = 0.055 L):
n = 1.1 * 0.055
n = 0.0605 mol
The molar mass of the substance can be calculated by the sum of the molar mass of each element, which can be found at the periodic table. Thus:
Ba = 137.33 g/mol
C = 12.00 g/mol
H = 1.00 g/mol
O = 16.00 g/mol
Ba(C2H3O2)2 = 137.33 + 4*12 + 6*1 + 4*16 = 255.33 g/mol
The molar mass is the mass divided by the number of moles, thus the mass (m) is the molar mass multiplied by the number of moles.
m = 255.33 * 0.0605
m = 15.45 g
Rounded by 2 significant digits, m = 15 g.
