Answer:
The same amount of matter exists before and after the change—none is created or destroyed. This concept is called the Law of Conservation of Mass.
In a physical change, a substance's physical properties may change, but its chemical makeup does not.
Explanation:
The oxidation number<span> of a Group 2 element in a </span>compound<span> is +2. The </span>oxidation number<span> of a Group 17 element in a binary </span>compound<span> is -1. The sum of the </span>oxidation numbers<span> of all of the atoms in a neutral </span>compound<span> is 0. The sum of the </span>oxidation numbers<span> in a polyatomic ion is equal to the charge of the ion.</span>
Answer:
Height z= 2.115 cm
Explanation:
The formula for area of a trapezoid is ;
A=1/2(a+b)h where A is area, a and b are the lengths of parallel sides and h is the height of the trapezoid.
Given in the question;
A= 20 cm²
a=( 2z + 3 ) cm
b= (6z-1) cm
h= z =? unknown
Substitute in the formula as;
A=1/2(a+b)h
20=1/2(2z+3+6z-1)z -----------multiply both sides of the equation by 2
40= (2z+3+6z-1)z -----------collect like terms as
40 =(2z+6z+3-1)z
40=(8z+2)z -----open brackets as
40=8z²+2z --------- form a quadratic equation
8z²+2z-40 = 0 -----solve the quadratic equation to find value of z
z²+0.25z-5=0
z= 2.115
Answer is: <span>the molarity of the diluted solution 0,043 M.
</span>V(NaOH) = 75 mL ÷ 1000 mL/L = 0,075 L.
c(NaOH) = 0,315 M = 0,315 mol/L.
n(NaOH) = c(NaOH) · V(NaOH).
n(NaOH) = 0,075 L · 0,315 mol/L.
n(NaOH) = 0,023625 mol.
V(solution) = 0,475 L + 0,75 L.
c(solution) = 0,023625 mol ÷ 0,550 L.
c(solution) = 0,043 mol/L.
I think it’s observation. But again I’m not sure.