Thursday

September 18, 2014

September 18, 2014

Total # Posts: 750

**Chemistry- Drbob-help**

I have placed the answer I got please help. A student makes a solution by dissolving 55.8 grams of potassium hydroxide in 875.0 grams of water. The resulting solution has a density of 1.07 grams per milliliter. 1. What is the volume of this solution? 870mL 2. Calculate the % ...
*February 9, 2011*

**chemistry**

How much NH3 can be produce from 20 liter 32,5 wt%(NH2)2CO (urea) aqueous solution. The reaction path way is : (NH2)2CO +H2O= 2NH3+ CO2 Thanx
*February 9, 2011*

**Chemistry**

A student dissolves 18.9 grams of Zn(NO3)2 [molar mass = 189] in enough water to make 500.0 of solution. A 100.0 ml portion of this solution is diluted to 1000.0 ml.What is the [NO3¯ ] in the second solution? A) 0.0100M B) 0.0200M C) 0.0300M D) 0.0400M E) 0.0500M
*February 9, 2011*

**Chemistry**

A student dissolves 18.9 grams of Zn(NO3)2 [molar mass = 189] in enough water to make 500.0 of solution. A 100.0 ml portion of this solution is diluted to 1000.0 ml.What is the [NO3¯ ] in the second solution? A) 0.0100M B) 0.0200M C) 0.0300M D) 0.0400M E) 0.0500M
*February 8, 2011*

**Math**

The reduced row echelon form of the matrix -1/2 1/2 3/2 -3/2 2 3/2 1/2 -3/2 9/2 is?
*February 6, 2011*

**Math**

The reduced row echelon form of the matrix -1/2 1/2 3/2 -3/2 2 3/2 1/2 -3/2 9/2 is?
*February 5, 2011*

**Chemistry**

A student makes a solution by dissolving 55.8 grams of potassium hydroxide in 875.0 grams of water. The resulting solution has a density of 1.07 grams per milliliter. 1. What is the volume of this solution? 2. Calculate the % concentration of this solution. 3. Calculate the ...
*February 1, 2011*

**Chemistry**

A student makes a solution by dissolving 55.8 grams of potassium hydroxide in 875.0 grams of water. The resulting solution has a density of 1.07 grams per milliliter. 1. What is the volume of this solution? 2. Calculate the % concentration of this solution. 3. Calculate the ...
*February 1, 2011*

**Chemistry**

A student makes a solution by dissolving 55.8 grams of potassium hydroxide in 875.0 grams of water. The resulting solution has a density of 1.07 grams per milliliter. 1. What is the volume of this solution? 2. Calculate the % concentration of this solution. 3. Calculate the ...
*January 31, 2011*

**Chemistry**

A student makes a solution by dissolving 55.8 grams of potassium hydroxide in 875.0 grams of water. The resulting solution has a density of 1.07 grams per milliliter. 1. What is the volume of this solution? 2. Calculate the % concentration of this solution. 3. Calculate the ...
*January 31, 2011*

**Chemistry**

what volume of 1.015mol/L magnesium hydroxide is needed to neutralize 40.0mL of 1.60mol/L hydrochloric acid. Can you work it out please? Thanks!
*January 27, 2011*

**Chemistry**

what volume of 1.015mol/L magnesium hydroxide is needed to neutralize 40.0mL of 1.60mol/L hydrochloric acid. Can you work it out please? Thanks!
*January 27, 2011*

**Chemistry**

8.76g of aluminum sulphide is added to 0.0350L of 0.250mol/L lead(II)nitrate solution. calculate the maximum mass of precipitate, PbS that can form
*January 27, 2011*

**Chemistry**

The following data is collected for the decomposition of methy isonitrile at various tempertures: Temp.(C)---{k(/s)} --- lnk---1/T 290--- {2.52*10^-5}--- ?--- ? 299--- {5.25*10^-5}--- ? --- ? 330--- {6.30*10^-4}--- ?--- ? Complete the table above and, using your graphing ...
*January 26, 2011*

**Chemistry**

The following data is collected for the decomposition of methy isonitrile at various tempertures: Temp.(C)---{k(/s)} --- lnk---1/T 290--- {2.52*10^-5}--- ?--- ? 299--- {5.25*10^-5}--- ? --- ? 330--- {6.30*10^-4}--- ?--- ? Complete the table above and, using your graphing ...
*January 26, 2011*

**Chemistry**

The following data is collected for the decomposition of methy isonitrile at various tempertures: Temp.(C) k(/s) lnk 1/T 290--- 2.52*10^-5 ? ? 299--- 5.25*10^-5 ? ? 330--- 6.30*10^-4 ? ? Complete the table above and, using your graphing calculator determine the value of the ...
*January 24, 2011*

**Chemistry**

NH4HS(s )<=>NH3(g)+ H2S(g) ∆H = +93 kilojoues The equilibrium,above is established by placing solid NH4HS in an evacuated container at 25degreesC. At equilibrium, some solid NH4HS remains in the container. Predict and explain the following. The effect on the ...
*January 14, 2011*

**Chemistry**

NH4HS(s) NH3(g) + H2S(g) ∆H_ = +93 kilojoules The equilibrium above is established by placing solid NH4HS in an evacuated container at 25°C. At equilibrium, some solid NH4HS remains in the container. Predict and explain each of the following. (a) The effect on the ...
*January 13, 2011*

**microeconomics**

1. Why might a profitable motel shut down in the long run if the land on which it is located becomes extremely valuable due to surrounding economic development? 1a. What kinds of costs are involved in making a decision to shut down?
*January 12, 2011*

**chem**

what are the normal freezing points and boiling points of the following solutions: a. 21.1g NaCl in 135mL of water b. 15.4g urea in 66.7 mL water?
*January 12, 2011*

**chem**

what are the normal freezing points and boiling points of the following solutions: a. 21.1g NaCl in 135mL of water b. 15.4g urea in 66.7 mL water?
*January 12, 2011*

**math**

A dice is 4cm in all sides. What if you enlarge it by 1/4. What will be the size of all its size in cm3??
*January 8, 2011*

**Science (Energy)**

Ok i have done 2 experiments (See below) the question i need help with is i need to explain the difference for the two combustions and i just dont know, please help me and thankyou for your help. The Combustion Of Marshmallows Aim To investigate how much energy is transferred ...
*December 17, 2010*

**physics **

How much paraffin oil would be needed to heat the same volume of water? • Heat capacity of water = 4200 j kg-1 K-1 • Mass of 1 litre of water = 1kg • Heat value of paraffin = 45M J kg-1 • Density of paraffin = 800kg m -3 • 1 cubic centimetre (1cm3 = 10...
*December 15, 2010*

**Physics **

How long would it take a kettle with a 1kW heating element to heat 1 litre of water? Watts = Joules / second • Mass of 1 litre of water = 1kg • 1 kW = 1 k Joule / second or 1000 joules/ second • 1g of water needs 4.184J to raise the temperature by 1̊ c. &#...
*December 15, 2010*

**reading**

Tell me about the bokk Eragon
*December 14, 2010*

**Chemstry**

A 5.00 gram mixture of CaO and CaCO3 is heated strongly. After heating, the mixture has a mass of 4.00 grams. What % of the original mixture is CaCO3?
*December 13, 2010*

**Chemistry**

A 5.00 gram mixture of CaO and CaO3 is heated strongly. After heating, the mixture it has a mass of 4.00 grams. What % of the original mixture is CaCo3?
*December 9, 2010*

**science**

can anyone give me 10 examples or energy interconversions and how they work please thankyou.
*December 5, 2010*

**science**

can anyone give me examples of energy intercoversions please
*December 5, 2010*

**math**

5-16/3=
*December 2, 2010*

**Math-3rd grade**

Round to estimate the sum of all the numbers in 14.
*December 1, 2010*

**4th grade**

$10
*December 1, 2010*

**chem class**

You did an extra step of 14-8.4. pH= -log[H+] -log[3.98x10^-9] = 8.400 pH=8.400
*November 21, 2010*

**Physics**

720kg
*November 21, 2010*

**mis**

Choose one of the following basic business processes: inventory management, operations and manufacturing, HR management, or accounting/financial management. Use the Internet to identify three vendors that license a product to support that process. Compare offerings from the ...
*November 19, 2010*

**Writing**

What type of tone would be appropriate for an informal report?
*November 18, 2010*

**algebra**

thanks just new way of putting it thansk
*November 17, 2010*

**algebra**

it says find the roots of each equation by factoring x^2+8x=-16
*November 17, 2010*

**Math**

this equation is writing as ax^2+bx+c you need to find x. the equation for x is x=b/2a plug it in b=24 a=4 x=24/2x4=24/8=3 if x = 3 plug it in to your equation 4(3)^2+24(3)+39 4x9+72+39 36+72+39=147 so the vertex is (3,147) because a is 24 its positive meaning it opens up ...
*November 17, 2010*

**science**

What other applications can be used with MS Excel to exchange information and data?
*November 16, 2010*

**algebra**

Y= 7 7=3(9)+b m=3 7=27+b x=9 27 27 b=-20 -20=b y=3x-20
*November 16, 2010*

**CALCULUS BC**

a particle moves on the x-axis in such a way that its position at time t is given by x(t)=3t^5-25^3+60t. for what values of t is the particle moving to the left. a.-2<t<1 only b.-2<t<-1 and 1<t<2 c.1<t<2 only d.-1<t<1 and t>2 e.t<-2,-1<t&...
*November 15, 2010*

**AP PHYSICS**

the height of the upper falls at Yellowstone falls is 33.2m. when the water reaches the botton of the falls, its speed is 25.8 m/s. neglecting air resistance, what is the speed of the water at the to of te falls.
*November 15, 2010*

**math - algebra**

how would i solve this using the substitution method 3y=11-x 3x-y=3 thanks
*November 14, 2010*

**physics**

A girl 36 kg occupies a seat of a swing that this subject by two chains 20 m in length each. If someone drops the girl from an 8 m position below the highest of the swing. What strength exercises it on the girl when she passes through the point lower?
*November 10, 2010*

**physics**

A girl 36 kg occupies a seat of a swing that this subject by two chains 20 m in length each. If someone drops the girl from an 8 m position below the highest of the swing. What strength exercises it on the girl when she passes through the point lower?
*November 10, 2010*

**Science**

I conducted an experiment of the heat of combustion for three alcohol fuels, methyl, propyl and ethyl. The results were: Methyl - mass before was 231.81g temp of water before heating was 15 deg c. temp of water after heating was 40 deg c. mass of methyl after heating 229.92g ...
*November 8, 2010*

**Business**

How can knowledge of the direct and indirect approaches help writers write “efficiently and effectively”?
*November 5, 2010*

**math**

yeah 421 too
*November 4, 2010*

**math**

if a 1 block means ones 10 block means tens and 100 block means 100s then the number would be 842 because 8 is 2 times as much as 4 and 4 is 2 times as much as 2
*November 4, 2010*

**math**

x=?
*November 3, 2010*

**math**

just do the problum backwards if you have the answer to the square root what you do is square that number ^5x=5 5x5= 25 ^25=5 so now that you have the number being square rooted all you have to do is find our the answer to this equation 5x?=25
*November 3, 2010*

**math **

a ratio is 60:120 one way i remember this is by saying it 60 TO 120 when you say a ratio you say to and when you use a fraction you say by.
*November 3, 2010*

**5th grade**

sorry that didint work well
*November 3, 2010*

**5th grade**

ok so your parallegram looks like this 5 l----\ 4l-----\ 7 so you know that the bottom line has 2 more meters then the top so what you do is you cut that off from the shape and think of it as a 5x4 rectangle 5 ______ [\ 4 [ ] 4[ \ [ ] [__\ ------ 2 4x5=20 4x2=8 8/2=4 find the ...
*November 3, 2010*

**math**

yes
*November 3, 2010*

**5th grade**

its hard to exsplane without signs google long division
*November 3, 2010*

**math**

i think your asking what the odds are that you will pick a odd number if picked from 36 cards numbered 1-36 if so 1 is pime 2 is prime 3 is prim 5 is prime 7 is prime 11 is prime 13 is prime 17 is prime 19 is prime 23 is prime 29 is prime 31 is prime and thats it so that means...
*November 3, 2010*

**math**

or 2/5
*November 3, 2010*

**math**

yes
*November 3, 2010*

**math**

a vowel is a,e,i,o,u so count how many letters there are in the word then count how many a,e,i,o,u, letters there there are then put the number of vowels there are over the amount of letters there are in the word then simplifiy
*November 3, 2010*

**Math**

you have to put it into a vertex form y=a(x-h)^2 +k y=x+4(because of sign ||)+8 now you have to get ^2 y=a(.5x-2)^2+8 y=1(.5x-2)^2+8 now k shifts up or down IE y axis h shifts left or right IE x axis but a +h=-h and a -h=+h so your vertex would be (2,8) because h is -2 and k is 8
*November 3, 2010*

**Math**

where do you get x3 from? do you mean 3x?
*November 3, 2010*

**math**

i dont understand 3/6 dose not equal 1/3 its 1/2
*November 3, 2010*

**math**

HELP!! the area A of the circle in the figure can be represented by A(r)=pi,r^2 where r is the radius what are the resonable domain and range for each function? explain the problme before this made me make a equation of B(r)=5^2-pi,r^2 im not sure if there asking this or A(r)=...
*November 3, 2010*

**math**

3a+8=15-(9a-9) 3a+8=15-1(9a-9) 3a+8=15-9a+9 +3a +3a 12a+8=15 -8 -8 12a=7 /12 /12 a=.5833 repeating
*November 3, 2010*

**algebra**

t would be 4 because 16/2x4=2 use pemdas multiply is before divide 16/8=2 right 2=2
*November 3, 2010*

**algebra**

if the with is 12 inches and the box takes thirty then you have 18 inches of ribbon left in the equation seeing how a box is a 3 dementinal figure it has 18 inches to share between 2 sides so you divide 18 by to and get 9 so the hight of your box would be 9
*November 3, 2010*

**Science**

I need to describe what a standard operating procedure is and what procedures it may involve. Thankyou.
*October 30, 2010*

**science**

I need to describe what a standard operating procedure is and what procedures it may involve. Thankyou.
*October 29, 2010*

**physics**

A block of mass 4.253 kg is released on the track at a height 5.52 m above the level surface. It slides down the track and makes a head-on elastic collision with a block of mass 17.012 kg, initially at rest. The acceleration of gravity is 9.8 m/s2 . Calculate the height to ...
*October 27, 2010*

**Writing**

What are the rules involved when using this type of formatting? How did the formatting of those messages affect their level of success? Please help with this question. thank you
*October 27, 2010*

**Writing**

Thank you very much, SraJMcGin and Ms. Sue
*October 27, 2010*

**Writing**

What are some strategies we can use to analyze our audiences? At which stage in the writing process should we analyze the audience?
*October 27, 2010*

**Biology**

Diffusion, Osmosis, Active Transport, Facilitated diffusion,
*October 20, 2010*

**6th Grade Math**

5-16/3=
*October 17, 2010*

**chemistry**

The equation for the reaction between hydrogen gas and oxygen gas is: 2H2(g) + O2(g) ---> 2H2O(l) i) How much hydrogen will react with 8g of oxygen? ii) how much water will be formed when 6g of hydrogen react? i would appreciate your help.
*October 17, 2010*

**chemistry**

The equation for the reaction between hydrogen gas and oxygen gas is: 2H2(g) + O2(g) ---> 2H2O(l) i) How much hydrogen will react with 8g of oxygen? ii) how much water will be formed when 6g of hydrogen react? i would appreciate your help.
*October 17, 2010*

**Chemistry**

In a simple titration experiment how and why are the results reproducible?
*October 15, 2010*

**2nd grade reasoning**

Explained: Look at the question: My tens digit is double my ones digit. I am less than 70 and greater than 60. what number am I? So 10’s digit is double my 1’s digit. 10's digit can only be in the range of 60 and 70, [61-69] So The 10's digit has to be 6 Read...
*October 14, 2010*

**psychology**

What will you take from this material on leadership and management and apply in your own life?
*October 13, 2010*

**psychology**

Should your boss ask you how to be a better leader and manager, what might you take from this material and suggest to him/her?
*October 13, 2010*

**psychology **

What in the material on "Groups" did you find useful? How will you apply it in your life?
*October 13, 2010*

**Science (Bonding)**

Can someone show me how to draw a dot and cross diagram for kf, showing only the outer electron shells. I remember doing it and school and learning that it was a ionic bond if i remember correctly. Thankyou.
*October 13, 2010*

**Working in the science industry**

thankyou Dr Bob222 and writeacher. All the best.
*October 13, 2010*

**Working in the science industry**

Can any one list the tasks and the precautions and give details of the job of a technician in the science industry. Many thanks. ps thankyou dr bob 222 but there was nothing there in your previous answer, can you help
*October 13, 2010*

**Science**

Dr Bob222 i can not see anything
*October 12, 2010*

**Science**

Can any one list the tasks and the precautions and give details of the job of a technician in the science industry. Many thanks.
*October 12, 2010*

**Chemistry**

How can i explain the key features of the periodic table relate to the conclusions after a titration experiment The experiment was the preperation of a standard solution of sodium carbonate and titration for the equation between hydrchloric acid and sodium carbonate Objective...
*October 11, 2010*

**Chemistry**

How can i explain the key features of the periodic table relate to the conclusions after a titration experiment
*October 11, 2010*

**algebra**

the final exam in a course will count as 30% of the total. prior to the final exam, 245 points are possible. how many points will the final exam be worth?
*October 9, 2010*

**Chemistry**

Preperation of a standard solution of sodium carbonate and titration for the equation between hydrchloric acid and sodium carbonate How can i explain the key features of the periodic table relate to the conclusions of the above experiment, i need to understand the groups, ...
*October 9, 2010*

**Chemistry**

They are formed by the _____________ of a ______________ of electrons First one is sharing and the second one is pair
*October 8, 2010*

**Chemistry**

Hello i have a few questions i need help with please, can you help me and thank you in advance..... What are covalent compounds usually formed between? I also have to fill in this sentence can you help.... They are formed by the _____________ of a ______________ of electrons ...
*October 8, 2010*

**Chemistry Help**

Calculate how many moles of NH_3 form when each quantity of reactant completely reacts 3N_2H_4(l)-->NH_3(g)+N_2(g) -2.5mol N_2H_4 -4.05mol N_2H_4 -65.8g N_2H_4 -4.52kg N_2H_4
*October 5, 2010*

**College Physics**

when the radius remains same, the speed should be increased.
*September 30, 2010*

**religion**

need help to unscramble words from the renaissance 1mgernay 2cahtcilo 3oppe 4gatrorypu 5formaretion
*September 29, 2010*

**English**

to show the other person how important he/she is to you.
*September 29, 2010*

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