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3 years ago

Why is a fan bald spinning at a constant speed constantly accelerating

Chemistry

1 answer:

Dennis_Churaev [7]3 years ago

6 0

Answer:

Explanation:

When an object moves in a circle at a constant speed its velocity (which is a vector) is constantly changing. Its velocity is changing not because the magnitude of the velocity is changing but because its direction is. This constantly changing velocity means that the object is accelerating (centripetal acceleration)

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The indicator methyl red has different molecular structures at high and low pH.

Novosadov [1.4K]

Answer:

a. True

Explanation:

Methyl red is an indicator widely used in quality control of oxides as Zinc oxide in the titration with sulfuric acid.

As is used in titrations of acid-base reactions the indicator change in colour. Is red when the pH < 4.4 (Acidic Solutions) and is yellow when pH > 6.2 (Neutral-Basic solutions).

A change in colour means the structure of the indicator is changing with pH. Thus, the answer is:

6 0

3 years ago

Zinc and hydrochloric acid react to form zinc chloride and hydrogen gas according to

stealth61 [152]

Explanation:

Mole ratio of Zn to HCl = 1 : 2.

If we use all 2.0mol of Zn, we would need 2.0 * 2 = 4.0mol of HCl. However we only have 3.0mol of HCl.

Therefore HCl is limiting.

6 0

4 years ago

A 52.0-mL volume of 0.35 M CH3COOH (Ka=1.8×10−5) is titrated with 0.40 M NaOH. Calculate the pH after the addition of 23.0 mL of

Georgia [21]

NaOH reacts with CH3COOH in 1:1 molar ratio to produce CH3COONa

NaOH + CH3COOH → CH3COONa + H2O

Mol CH3COOH in 52.0mL of 0.35M solution = 52.0/1000*0.35 = 0.0182 mol CH3COOH

Mol NaOH in 19.0mL of 0.40M solution = 19.0/1000*0.40 = 0.0076 mol NaOH

These will react to produce 0.0076 mol CH3COONa and there will be 0.0182 - 0.0076 = 0.0106 mol CH3COOH remaining in solution unreacted . Total volume of solution = 52.0+19.0 = 71mL or 0.071L

Molarity of CH3COOH = 0.0106/0.071 = 0.1493M

CH3COONa = 0.0076 / 0.071 = 0.1070M

pKa acetic acid = - log Ka = -log 1.8*10^-5 = 4.74.

pH using Henderson - Hasselbalch equation:

pH = pKa + log ([salt]/[acid])

pH = 4.74 + log ( 0.1070/0.1493)

pH = 4.74 + log 0.717

pH = 4.74 + (-0.14)

pH = 4.60.

7 0

3 years ago

The radioactive decay of a certain sample produced 846 disintegrations per minute. exactly 3.00 days later, the rate of decay wa

Margarita [4]

Answer:

$\boxed{\text{1.81 da}}$

Explanation:

1. Calculate the decay constant

The integrated rate law for radioactive decay is 1

$\ln\dfrac{A_{0}}{A_{t}} = kt$

where

A₀ and A_t are the counts at t = 0 and t

k is the radioactive decay constant

$\ln \dfrac{846}{269} = k \times 3.00\\\\\ln3.145 = 3.00k\\1.146 = 3.00k\\\\k =\dfrac{1.146}{3}\\\\k = \text{0.382 /da}\\$

2. Calculate the half-life

$t_{\frac{1}{2}} = \dfrac{\ln2}{k} = \dfrac{\ln2}{0.382} = \text{1.81 da}$

The half-life for decay is $\boxed{\textbf{1.81 da}}$ .

3 0

4 years ago

How do the ionic radii vary within a group of non-metals?

stellarik [79]

Answer: Ionic radii is half the distance between two ions.

Explanation: from top to bottom down an element group, ionic radius increases. This is because a new electron shell is added as you move down the periodic table.

Might Be wrong not sure :)

8 0

3 years ago