What two elements combine to form a water molecule
hydrogen and oxygen
carbon and oxygen
hydrogen and chlorine
sulphur and oxygen
What does the pH scale measure
number of oxygen ions
number of water ions
number of hydrogen ions
number of alkaline ions
What is the ph of neutral water
6
7
8
9
what is the difference in the hydrogen ion conventration from ph4 to ph5
10 000 times as strong
1000 times as strong
100 times as strong
10 times as strong
what effect does acidic water have on ferrous piping materials
corrosion
coating
carbonization
scaling
What causes temporary hardness
calcium carbonates
magnesium carbonates
acidity
calcium and/or magnesium bicarbonates
why should a hot water tank be set at a temperature below 50C
a prevent permanent hardness from settling out
to prevent total hardness from settling out
to prevent carbonates of calcium and magnesium from settling out
to prevent temporary hardness from settling out
what is the buoyant force available on a 5ft3 object if it is immersed in water
49lb
123.48lb
312lb
5000lb
what is the volume of an object that weighs 925 kg when weighed in air, but only 570 kg when weighed in water
5.689m3
0.925m3
0.57m3
0.355m3
what will an object with a volume of 0.658ft3 an a weight of 40lb o when placed in water
sink
remain in equilibrium, neither sinking nor rising
barely float with most of the object submerged
float high on the water, with very little submerged
How much extra weight would be required to sink a sealed drum with a volume of 2.725m3 and a mass of 22.7kg
2 726kg
19 976kg
2 703.3kg
22 701kg
what is the pressure exerted by 80' head of water
8.15psi
34.64 psi
184.75psi
784psi
Which of the following is a correct definition of flow rate
speed of the fluid in a pipe
pressure of the fluid in a pipe
volume of the fluid in a pipe
the quantity moving in a pipe
what is one major contributor to turbulent flow
high velocity
long runs of straight piping
correct reaming of the pipe
large flow rates
which one of the following factors does not affect the pressure loss in the flow of fluids in a piping system
viscosity of the fluid
size of the piping
number of fittings and valves
static pressure in the piping system
what is one probable cause of water hammer
too many hangers supporting the piping
a quick closing valve
a sudden increase in pipe size
too many valves open at the same time
what is the relationship between pressure an velocity in the narrowest portion of a venturi
pressure increases, velocity decreases
pressure increases, velocity increases
pressure decreases, velocity decreases
pressure decreases, velocity increases
what causes cavitation
excessive pressure in the pump discharge
vapour bubbling forming in a low pressure area
vapour bubbles forming in a high pressure area
corroded pipe collapsing
how do you find the amount of expansion
lengthxtemp changex co effecient of expansion
heightxtemp change x coeffecient of expansion
The Term pH is used to indicate the level of acidity fluidity( acidity, fluidity ) or alkalinity solubility( alkalinity, solubility ) within a solution
The pH of water can be broken down into two parts hydrogen ions hydrogen atoms( hydrogen ions, hydrogen atoms )(H+) hydroxyl ions hydroxyl atoms( hydroxyl ions, hydroxyl atoms ) (OH-)
When an atom loses an electron it becomes a positive negative( positive, negative ) ion
When an atom picks up a free electron it becomes a negative positive( negative, positive ) ion
The pH scale mathematically relates the concentration of hydrogen hydroxyle( hydrogen, hydroxyle ) ions
0 on the pH scale is Highly Acidic Alkaline( Acidic, Alkaline )
A pH value of 14 is considered highly Alkaline Acidic( Alkaline, Acidic )
Acidic Alkaline( Acidic, Alkaline ) water has a corrosive effect
Velocity increases decreases( increases, decreases ), pressure decreases increases( decreases, increases ) and as velocity decreases increases( decreases, increases ) pressure increases decreases( increases, decreases )
The trade off between velocity energy and head pressure energy can be seen characteristic of water flow, which is commonly known as water hammer hammer time( water hammer, hammer time )
Cavitation water hammer( Cavitation, water hammer ) is a very destructive process that occurs in a liquid flowing in a piping system.
Pressure = Height x Density of liquid Width x Density of liquid( Height x Density of liquid, Width x Density of liquid ) Pressure= 35' x 0.433 lb/in2/ft Pressure=15.115 psi
15.115psi is equal to the pressure exerted by a column of water 35' high but we want an additional 4 psi at the highest point of the system Therefore, add 15.115psi=4psi =19.155
0.433 9.81( 0.433, 9.81 )lb/in2/ft
9.81 0.433( 9.81, 0.433 )KPa/m
The height is 90' to gauge B the first gauge reads 60psig
Pressure = 60psig-90'x0.433psi=21.03psig Gauge B would read 21.03 psig 23 psig( 21.03 psig, 23 psig )
Boyle's Law Charles Law( Boyle's Law, Charles Law ) - Variables: pressure, volume and temperature
As the pressure from the mercury was increased decreased( increased, decreased ), the volume of the air decreased increased( decreased, increased )
It is important to note that boyle's Law is based upon absolute pressures pressures( absolute pressures, pressures ) and all gauge pressures must be converted to absolute before any calculations can be done.
The formula for boyles law chucks law( boyles law, chucks law ) is
v1/V2=P2/P1 or P1V1=P2V2
V1 =the original volume V2=the new volume P1=the original pressure P2=the new pressure
Charles law is the law, temperature pressure( temperature, pressure ) and volume pressure( volume, pressure ) are in a direct relationship
Charles Law uses absolute temperatrues not absolute temperatues( absolute temperatrues, not absolute temperatues )
(100F+460 100( 460, 100 ))= 560R(Rankine)
100C+273 470( 273, 470 )=373K(Kelvin)
Similar to Charles Law, Guy-Lussac's Law examines the relationship between temperature height( temperature, height ) and pressure width( pressure, width )
All three variables(volume,pressure and temperature)are included in the combined Gas Law. In this law, a change in one variable will will not( will, will not ) affect the other two variables
65 x 1.414=91.91 50 x 1.414=70.7 162.61 650+650=1300-162.61 1137 200( 1137, 200 )
Total hardness
1mg/L=1ppm
soft - 0-50 50-100( 0-50, 50-100 )mg/L moderately soft- 50-100 100-150( 50-100, 100-150 )mg/L moderately hard- 100-150 150-200( 100-150, 150-200 )mg/L Hard- 150-200 200( 150-200, 200 )mg/L Very Hard- over 200 300( 200, 300 )mg/L
Very hard water is unfit for human consumption or potable water supplies unless softened by treating the water to less than 200 mg/L 150 mg/L( 200 mg/L, 150 mg/L )
We use the term hardness to designate the amount of these dissolved minerals rocks( minerals, rocks ) contained in the water.
-Temporary harness -permanent hardness and -total hardness
Temporary hardness Permanent hardness( Temporary hardness, Permanent hardness ) is Bicarbonates of calcium and magnesium dissolved in the water cause temporary hardness. This occurs at approximately 60C(140F). For this reason the thermostats must not be set at temperatures greater than 60C(140F)
Permanent hardness Temporary harness( Permanent hardness, Temporary harness ) is carbonates of calcium and magnesium in addition sulfates,nitrates and chlorides of other elements. This does not occur unless the water is heated above 148C(299F)
Oxidation jack ass( Oxidation, jack ass ) is water containing dissolved air, which is composed of nitrogen and oxygen
Solubility bounceility( Solubility, bounceility ) temperature affects the solubility of dissolved chemical in water. Temperatures above 60C result in temporary hardness.
Density and expansion bobs mom( Density and expansion, bobs mom ) is an increase in temperature produces a change in the density of water for example a cubic meter of water at 4C has a mass of 1000kg, but at 100C the mas becomes 958.05kg. As temperature increased, molecular motion also increased and the molecules occupied a larger space.
Archimedes Principle Bobs principle( Archimedes Principle, Bobs principle ) A body, immersed in a fluid, loses as much weight as the weight of the fluid it displaces
The three laws of buoyancy laws of banking( laws of buoyancy, laws of banking ) are
1. A body sinks in a fluid if the mass of the fluid displaced is less than the mass of the body
2. If a body displaces a mass of fluid greater than its own mass, it will float.
3. body remains in equilibrium neither rising nor sinking if the mass of the fluid it displaces equals its own mass
Buoyant force The force( Buoyant force, The force )=weight of the liquid displaced
If the object weighs more than 156 lb, it will sink float( sink, float )
If the object weighs less than 156 lb it will float sink( float, sink )
Mass your mom( Mass, your mom )=volume x density
volume of the anchor = 100lb/480lb/ft cubic= 0.2083 ft3
buoyant force bob( buoyant force, bob ) availabe= 0.2083ft cubic x 62.4 lb/ft cubic= 12.99 lb
when we lift the anchor in the water it will require 100lb-12.99lb= 87.01 lb of force to lift the anchor
10' of head of water wold equal a pressure of 10'x0.433psi/ft=4.33 or and( or, and ) conversely, a pressure of 50psi/0.433psi/ft= 115.473'
In laminar turbulent( laminar, turbulent ) or streamline flow the water particles move in a straight line paths parallel to the walls of the pipe
In turbulent laminar( turbulent, laminar ) flow the pattern is highly irregular, with a constant churning of water from side to side, top to bottom
Viscosity dancing( Viscosity, dancing ) is the property of a liquid to resist flow
Pressure loss hey pauly( Pressure loss, hey pauly ) the amount of energy spent to over come the resistance of flow(friction is called pressure loss or pressure drop
For example , a !" pipe with a flow rate of 8 US gallons/minute has a pressure loss of 7.8'(3.4psi) of head per one hundred feet of length
The eye mouth( eye, mouth ) of the impellar is a low pressure area, and the vapor bubbles implode at high pressure areas
