Answer: The weight/weight % or percent by mass of the solute is 5.41 %.
Explanation:
Mass of the sodium sulfate,w = 9.74 g
Volume of the water = 165 mL
Density of the water = 1 g/mL
Mass of the water =
Mass of the solution, W:
Mass of solute + Mass of solvent =9.47 g + 165 g=174.47 g
The weight/weight % or percent by mass of the solute is 5.41 %.
Rutherford was one of the early scientists who worked on the atomic model. Before his discovery of the nucleus, the widely accepted theory was J.J Thomson's Plum Pudding Model. In this model, all the protons, electrons and neutrons are in the nucleus. But the electrons are more in number such that the electrons act as the 'pudding' and the proton and nucleus the 'plum'. This was Rutherford's hypothesis in his gold foil experiment. In order to test the Plum Pudding model, he hypothesized that when a beam of light is aimed at the atom, it would not diffract because the charges in the nucleus are well-distributed. However, his experiment disproved Thomson's model. Some light indeed passed through but a few was diffracted back to the source. He concluded that this was because there is a dense mass inside the atom called nucleus. Thus, from there on, he proposed the model that the electrons are orbiting around the nucleus.
The given question is incomplete. The complete question is:
Which is true of Elements on a periodic table in the same group (family)?
A; Elements in the same family have similar chemical properties because they have the same number of electron shells.
B; Elements in the same family have similar chemical properties because they have the same number of valence electrons.
C; Elements in the same family have few similar properties as they have different numbers of electron shells.
D; Elements in the same family are always the same type of Elements and have the same number of protons.
Answer: B; Elements in the same family have similar chemical properties because they have the same number of valence electrons.
Explanation:
Elements are distributed in groups and periods in a periodic table.
Elements that belong to same groups will show similar chemical properties because they have same number of valence electrons.
The chemical reactivity of elements is governed by the valence electrons present in the element.
Example: Flourine, chlorine and bromine are elements which belong to Group 17. They have 9, 17 and 35 electrons respectively and contain 7 valence electrons each and need one electron to complete their octet.
Answer : The molar mass of an acid is 266.985 g/mole
Explanation : Given,
Mass of an acid (HX) = 4.7 g
Volume of NaOH = 32.6 ml = 0.0326 L
Molarity of NaOH = 0.54 M = 0.54 mole/L
First we have to calculate the moles of NaOH.
Now we have to calculate the moles of an acid.
In the titration, the moles of an acid will be equal to the moles of NaOH.
Moles of an acid = Moles of NaOH = 0.017604 mole
Now we have to calculate the molar mass of and acid.
Now put all the given values in this formula, we get:
Therefore, the molar mass of an acid is 266.985 g/mole
The poly atomic ion formula for ammonium would be NH4+
