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2 years ago

Cathodic protection of a metal pipe against corrosion usually entails __________.

Chemistry

1 answer:

Yuliya22 [10]2 years ago

3 0

Answer:

C. attaching an active metal to make the pipe the cathode in an electrochemical cell.

Explanation:

Cathodic protection is a technique which helps in controlling the increased rate of corrosion of a metal surface by making it the cathode of an electrochemical cell. It connects the metal to be protected to a more easily corroded which is usually referred to as the sacrificial metal to act as the anode.

This technique preserves the metal by providing a highly active metal that can act as an anode and provide free electrons. By introducing these free electrons, the active metal sacrifices its ions and keeps the less active steel from corroding.

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Compute 4.659×104−2.14×104. Round the answer appropriately.

pentagon [3]

Answer: 25,200.

Explanation:

1) Given: 4.659 × 10⁴ - 2.14 × 10⁴

2) You have to deal with significant figures.

Since, the powers are the same (10⁴) you can directly subtract the decimal numbers. But first analyze the significant figures and the number of decimal digits.

3) The number 4.659 × 10⁴ has four significant figures (4, 6, 5, and 9), while the number 2.14 × 10⁴ has three significan figures (2, 1, and 4).

4) When you add or subtract numbers with diferent amount of decimal digits, the result must show the same number of decimal digits as the term with the least number of decimal digits.

5) Before subtracting, you must round all the terms to the least number of decimal digits. So, since 2.14 has two decimal digits and 4.659 has three decimal digits, you shall round 4.659 to 4.66.

6) Now you subtract 4.66 - 2.14 = 2.52

7) Multiply by the power of 10: 2.52 × 10⁴ = 25,200. And that is the answer.

5 0

2 years ago

Read 2 more answers

Consider a buffer solution containing CH3COOH and CH3COO-, with an equilibrium represented by: CH3COOH(aq) + H2O (l) ←----→ H3O+

Irina-Kira [14]

Answer:

Here's what I get.

Explanation:

(a) The buffer equilibrium

The equation for the buffer equilibrium is

$\rm CH_{3}COOH(aq) + H$_{2}$O(l) $\, \rightleftharpoons \,$ CH$_{3}$COO$^{-}$(aq) + H$_{3}$O$^{+}$(aq)$

(b) Addition of acid

If you add a strong acid like HNO₃, you are increasing the concentration of hydronium ion.

Per Le Châtelier's Principle, the system will respond in such a way as to decrease the concentration of hydronium ion.

The position of equilibrium will shift to the left.

(c) Addition of base.

If you add a strong base like KOH, The hydroxide ions will react with the hydronium ions to form water.

The concentration of hydronium ions will decrease.

Per Le Châtelier's Principle, the system will respond in such a way as to increase the concentration of hydronium ions.

The position of equilibrium will shift to the right.

5 0

2 years ago

A 150 W electric heater operates for 12.0 min to heat an ideal gas in a cylinder. During this time, the gas expands from 3.00 L

Brut [27]

<u>Answer:</u> The change in internal energy of the gas is 108.835 kJ

<u>Explanation:</u>

To calculate the work done for reversible expansion process, we use the equation:

$W=P\Delta V=-P(V_2-V_1)$

where,

W = work done

P = pressure = 1.03 atm

$V_1$ = initial volume = 3.00 L

$V_2$ = final volume = 11.0 L

Putting values in above equation, we get:

$W=-(1.03)\times (11.0-3.00)=8.24L.atm=834.9J=0.835kJ$ (Conversion factor: 1 L. atm = 101.325 J)

Calculating the heat from power:

$Q=P\times t$

where,

Q = heat required

P = power = 150 W

t = time = 12 min = 720 s (Conversion factor: 1 min = 60 s)

Putting values in above equation:

$Q=150\times 720=108000J=108kJ$

The equation for first law of thermodynamics follows:

$Q=dU+W$

where,

Q = total amount of heat required = 108 kJ

dU = Change in internal energy = ?

W = work done = -0.835 kJ

Putting values in above equation, we get:

$108kJ=dU+(-0.835)\\\\dU=(108+0.835)=108.835kJ$

Hence, the change in internal energy of the gas is 108.835 kJ

7 0

2 years ago

X-rays have a wavelength small enough to image individual atoms, but are challenging to detect because of their typical frequenc

Cerrena [4.2K]

Explanation:

Given: $\lambda = 8.38\:\text{nm} = 8.38×10^{-9}\:\text{m}$

Its frequency $\nu$ is defined as

$\nu = \dfrac{c}{\lambda} = \dfrac{3×10^8\:\text{m/s}}{8.38×10^{-9}\:\text{m}}$

$\:\:\:\:= 3.58×10^{16}\:\text{Hz}$

7 0

1 year ago

Which of these is a base? a-vinegar b-ammonia c-HCl d- HNO3

Lady_Fox [76]

B- ammonia. ammonia has a pH level of about 11, and anything higher than 7 is more basic and anything less than 7 is more acidic. 7 is considered neutral.

6 0

2 years ago

Read 2 more answers