For each of the following, use the periodic table to determine the number of valence electrons in an atom of the element.

marusya05 [52]

Answer: 27.09 ppm and 0.003 %.

First, for air pollutants, ppm refers to parts of steam or gas per million parts of contaminated air, which can be expressed as cm³ / m³. Therefore, we must find the volume of CO that represents 35 mg of this gas at a temperature of -30 ° C and a pressure of 0.92 atm.

Note: we consider 35 mg since this is the acceptable hourly average concentration of CO per cubic meter m³ of contaminated air established in the "National Ambient Air Quality Objectives". The volume of these 35 mg of gas will change according to the atmospheric conditions in which they are.

So, according to the law of ideal gases,

PV = nRT

where P, V, n and T are the pressure, volume, moles and temperature of the gas in question while R is the constant gas (0.082057 atm L / mol K)

The moles of CO will be,

n = 35 mg x $\frac{1 g}{1000 mg}$ x $\frac{1 mol}{28.01 g}$

→ n = 0.00125 mol

We clear V from the equation and substitute P = 0.92 atm and

T = -30 ° C + 273.15 K = 243.15 K

V = $\frac{0.00125 mol x 0.082057 \frac{atm L}{mol K} x 243 K}{0.92 atm}$

→ V = 0.0271 L

As 1000 cm³ = 1 L then,

V = 0.0271 L x $\frac{1000 cm^{3} }{1 L}$ = 27.09 cm³

Then the acceptable concentration c of CO in ppm is,

c = 27 cm³ / m³ = 27 ppm

To express this concentration in percent by volume we must consider that 1 000 000 cm³ = 1 m³ to convert 27.09 cm³ in m³ and multiply the result by 100%:

c = 27.09 $\frac{cm^{3} }{m^{3} }$ x $\frac{1 m^{3} }{1 000 000 cm^{3} }$ x 100%

c = 0.003 %

So, the acceptable concentration of CO if the temperature is -30 °C and pressure is 0.92 atm in ppm and as a percent by volume is 27.09 ppm and 0.003 %.

5 0

3 years ago

A 5.0-gram sample of Fe(s) is to be placed in 100. milliliters of HCl(aq). Which changes will result in the fastest rate of reac

guajiro [1.7K]

Raising the temperature of the reactants increases the reaction between the reactants. The kinetic energy of the molecules of the reactants collides more frequently with ach other thereby increasing its reaction. Increasing the concentration of the reactants increases the reaction rate. Adding a catalyst to the reaction increases the rate of reaction of a substance. The catalyst hastens the chemical reaction.

8 0

3 years ago

Define the term inertia

n200080 [17]

Answer:

Explanation:

Enertia is an integral part of Newton's first law of motion.

It is the tendency of an object to stay at rest or to continue moving until and unless any external unbalanced force, (like, applied force or force of tension or frictional force ) is applied to either move it from rest or change its speed(in other words, accelerate it!!).

Example below, is of ball at rest (fig1) and if this ball is moving straight on a frictionless surface(like ice) it will keep moving!! until, we push it or pull it.

5 0

4 years ago

A solid object has a mass of 1.62 lb and a volume of 190 mL.

Pachacha [2.7K]

The density of a solid object that has a mass of 1.62 lb and a volume of 190 mL is 3.87g/mL.

<h3>How to calculate density?</h3>

Density is the measure of the mass of matter contained by a unit volume. It can be calculated by dividing the mass of the substance by its volume.

According to this question, a solid object is said to have a mass of 1.62 lb and a volume of 190 mL.

1 pound = 453.592 grams

1.62 Ibs is equivalent to 734.82 grams

Density of the solid object = 734.82 grams ÷ 190 mL

Density = 3.87g/mL

Therefore, the density of a solid object that has a mass of 1.62 lb and a volume of 190 mL is 3.87g/mL.

Learn more density at: brainly.com/question/20337365

#SPJ1

8 0

1 year ago

Question 4 (higher question)

Jet001 [13]

Answer:

Explanation:

Describe means you should recall facts, events or processes accurately. You might need to give an account of what something looked like, or what happened.

Explain means you need to make something clear, or state the reasons for something happening.

Compare means you need to describe similarities and differences between things. If you are asked to compare X and Y, write down something about X and something about Y, and give a comparison. Do not just write about X only or Y only.

Evaluate means you must use information supplied, or your own knowledge, to consider the evidence for and against or to identify strengths and weaknesses. You must then complete your answer with a conclusion, stating which is better and why, for example.

8 0

3 years ago