<h3><u>Answer;</u></h3>
C) A convex lens has a thick center and thin edges; a concave lens has a thin center and thicker edges.
<h3><u>Explanation;</u></h3>
- Convex lens refers to the lens which merges the light rays at a particular point, that travels through it, while a concave lens can be identified as the lens which disperses the light rays around, that hits the lenses.
- A convex lens is thicker at the center, as compared to its edges, while a concave lens is thinner at the center as compared to its edges.
- A concave lens is thicker at the edges than in the middle and spreads light rays apart producing an image smaller than the actual object. A convex lens on the other hand, is thinner at the edges and thicker towards the center, that is they are bent towards a central point.
Fireworks owe their colors to reactions of combustion of the metals present. When Mg and Al burn, they emit a white bright light, whereas iron emits a gold light. Besides metals, oxygen is necesary for the combustion. The decomposition reactions of barium nitrate and potassium chlorate provide this element. At the same time, barium can burn emitting a green light.
(a) Barium nitrate is a <em>salt</em> formed by the <em>cation</em> barium Ba²⁺ and the <em>anion</em> nitrate NO₃⁻. Its formula is Ba(NO₃)₂. Potassium chlorate is a <em>salt</em> formed by the <em>cation</em> potassium K⁺ and the <em>anion</em> chlorate ClO₃⁻. Its formula is KClO₃.
(b) The balanced equation for the decomposition of potassium chloride is:
2KClO₃(s) ⇄ 2KCl(s) + 3O₂(g)
(c) The balanced equation for the decomposition of barium nitrate is:
Ba(NO₃)₂(s) ⇄ BaO(s) + N₂(g) + 3O₂(g)
(d) The balanced equations of metals with oxygen to form metal oxides are:
- 2 Mg(s) + O₂(g) ⇄ 2 MgO(s)
- 4 Al(s) + 3 O₂(g) ⇄ 2 Al₂O₃(s)
- 4 Fe(s) + 3 O₂(g) ⇄ 2 Fe₂O₃(s)
<span>The electronic configuration of cobalt is :1s2 2s2 2p6 3s2 3p6 3d7 4s2 </span>
Answer:One mole of HBr has 6.02 x 1
0
23
molecules of HBr.
1 mole of HBr = 6.02 x 1
0
23
molecules of HBr.-----(a)
X mole of HBr has 1.21 x
10
24
molecules of HBr.
X mole of HBr = 1.21 x
10
24
molecules of HBr------(b)
Taking ratio of (a) and (b)
X / 1 = 1.21 x
10
24
/ 6.02 x 1
0
23
X= 2.009 moles.
Explanation:
Answer:
A tiny sense positively charge core called a nucleus in which nearly all the mass is concentratedm
