Vacuum filtration is a process of separating the solid from liquids. A Buchner funnel and side arm flask is used for this process. The filter paper is placed on the Buchner funnel, the size of the filter paper should fit on the funnel and should cover all the holes. To obtain the correct yield of the solid product from the vacuum filtration process, there should be no gaps around the edges of the filter paper as if there are any gaps around the edges of the filter paper, the solid precipitate will pass through the gaps with liquid and thus, results in the low percentage yield of the solid compound.
Hence, to obtain the correct yield percentage of the solid compound there should be no gaps around the edges of the filter paper during the vacuum filtration.
Measurements may be accurate, meaning that the measured value is the same as the true value; they may be precise, meaning that multiple measurements give nearly identical values (i.e., reproducible results); they may be both accurate and precise; or they may be neither accurate nor precise. The goal of scientists is to obtain measured values that are both accurate and precise.
Suppose, for example, that the mass of a sample of gold was measured on one balance and found to be 1.896 g. On a different balance, the same sample was found to have a mass of 1.125 g. Which was correct? Careful and repeated measurements, including measurements on a calibrated third balance, showed the sample to have a mass of 1.895 g. The masses obtained from the three balances are in the following table:
Answer:
D
Explanation:
beacause all the elements in period 3 has different valence electrons hence you look at the first element in period 3 is sodium which has a valence electron of 1 when you go across the period to the right their valence electron decreases to be negative
Answer:
Explanation:
a ) period 4 noble gas is krypton
isoelectronic with it are Sr ⁺² and Br⁻
compound is SrBr₂
b ) Period 3 noble gas is Argon
isoelectronic with it are Mg⁺² and O⁻²
compound is MgO
c) 2+ ion is the smallest with a filled d subshell is Zn⁺² , smallest halogen
is F⁻
compound is ZnF₂
d ) ions from the largest and smallest ionizable atoms in Period 2
Li⁺ and F⁻
compound is LiF
Answer:
Holly observes that the ice pack becomes colder when she activates it.
Explanation:
She infers that the process of the urea dissolving in water is endothermic.