There are types of lens; concave and convex lens.
The concave lens is a lens which has an inward curve in the middle, that is, the edges of the curve are thicker than the center of the lens, because of this, any light that enter the lens will spread out [diverge]. An image will look smaller and upright when viewed by a concave lens. Image formed by concave lens are usually VIRTUAL.
A concave lens will produce a real image ONLY if the object is located beyond the focal point of the lens.
A convex lens is a converging lens, this is because, the center of the lens is thicker than its edges. Any ray of light that passes through the lens will converge at the middle of the lens at point called principal focus. A convex lens produce a VIRTUAL image when the object is placed infront of the focal point. The virtual image formed is always magnified and upright.<span />
Answer:
A. 0.90 L.
Explanation:
- NaOH solution will react with H₂SO₄ according to the balanced reaction:
<em>H₂SO₄ + 2NaOH → Na₂SO₄ + 2H₂O.</em>
<em>1.0 mole of H₂SO₄ reacts with 2.0 moles of NaOH.</em>
- For NaOH to react completely with H₂SO₄, the no. of millimoles should be equal.
<em>∴ (MV) NaOH = (xMV) H₂SO₄.</em>
x for H₂SO₄ = 2, due to having to reproducible H⁺ ions.
<em>∴ V of NaOH = (xMV) H₂SO₄/ M of NaOH</em> = 2(0.6 L)(3.0 M)/(4.0 M) = <em>0.90 L.</em>
Answer:
Option C, (Actual yield ÷ percent yield) × 100
Explanation:
Theoretical yield is defined as the total amount of product formed for given reactants in a chemical reaction. It is an ideal case which assumes no exceptions or wastage.
The mathematical relation between the actual yield, percent yield and theoretical yield is as follows -

Where
P.Y. represents the percent yield a
M A.Y. represents the mass obtained from actual yield
M T.Y. represents the mass obtained from theoretical yield
Hence, if we rearrange the formula, we get -

Hence, option C is correct
117 mL of 0.210 M K₂S solution
Explanation:
The question asks about the volume of 0.210 M K₂S (potassium sulfide) solution required to completely react with 175 mL of 0.140 M Co(NO₃)₂ (cobalt(II) nitrate).
We have the chemical reaction:
K₂S + Co(NO₃)₂ → CoS + 2 KNO₃
molar concentration = number of moles / volume (L)
number of moles = molar concentration × volume
number of moles of Co(NO₃)₂ = 0.140 × 175 = 24.5 mmoles
We see from the chemical reaction that 1 mmole of Co(NO₃)₂ is reacting with 1 mmole of K₂S, so 24.5 mmoles of Co(NO₃)₂ are reacting with 24.5 mmoles of K₂S.
volume = number of moles / molar concentration
volume of K₂S solution = 24.5 / 0.210 = 117 mL
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molar concentration
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Answer:
Kim kim kim kim kim ath marath enthe kantha
Explanation:
Ninn chumbenem enne thellerthii.
Nin vadabell enne shwasichu!