<u>Answer:</u>
The correct answer option is a. Selenium (Se).
<u>Explanation:</u>
From the given answer options, Selenium (Se) is the only element which is a non metal.
It has the atomic number 34 with atomic weight 78.96. It is a member of the sulfur group of the non metallic elements and falls in period 4 of the Periodic table.
Selenium has non metallic properties which are intermediate between the elements that lie above and below it in the Periodic table.
<span>For number
two, the equation is balanced. Na in the reactant side has one atom and also in
the product side. O has only one atom in the product and in the reactant. There
are 2H’s in the reactant and in the product side (present in H2O, the 2 in H
stands for 2 atoms of H). One atom of Cl is present in the reactant and product
side.</span>
For number
three, the reactants are NaOH-sodium hydroxide and HCl-hydrogen
chloride(hydrochloric acid). The products are NaCl-sodium chloride and
H2O-water.
Answer: 12,6 gam
Explanation: Hãy thử xem bạn có đồng ý không, tôi đang bối rối
Answer:
Constant pressure of gas must have a constant volume and a constant number of moles of gas. It's equation is the ideal gas law: pV=nRT
Explanation:
The gas state is the most excited state. It doesn't have a definite volume or shape which is why it can be compressed. Gas pressure is basically the result of all the gas particles moving around and colliding against each other and their container. The rate this happens at as well as its force determines the pressure. Since there are many, many of these gas particles in all quantities of gas, the fluctuation of this rate as well as its intesity is nearly constant.
A 0.250 L solution of NH4Cl contains (0.250 L)(0.35 mol/L) = 0.0875 moles of dissolved NH4Cl. Converting this quantity to mass, we get (0.0875 mol NH4Cl)(53.491 g/mol) = 4.7 g NH4Cl (two significant figures).
So, approximately 4.7 g of NH4Cl dissolved in a 0.250 L solution will have a concentration of 0.35 L.
