Tuesday
September 16, 2014

Posts by denis


Total # Posts: 44

Geometry
Find 2 cos(x/2) sin(x/2) when x = -π/6. I know that cos(x/2) = +- sqrt(1-cosx)/2 and sin(x/2) = +- sqrt(1+cosx)/2, but how to use this identity I'm not entirely sure. Please help.
August 6, 2014

Chemistry
indium-115 has a half life of 4.5 hours, if you start with a 12.0mg sample of indium-115, how much will remain after 13.5 hours
May 29, 2014

biology
how can you recognize carbohydrates from a list of biological molecules
September 23, 2012

b
how can a disaccharide be produced from two monosaccharides
September 23, 2012

biological
how can a disaccharide be produced from two monosaccharides
September 22, 2012

biology
how can you recognize carbohydrates from a list of biological molecules
September 22, 2012

microbiology
what is sugar fermentation
April 19, 2012

sociology
examine the latent and manifest functions ( of the US response to 9/11. Consider how the emerging structures of society are functional and/or dysfunctional for the nation.
April 3, 2012

sociology
examine the latent and manifest functions ( of the US response to 9/11. Consider how the emerging structures of society are functional and/or dysfunctional for the nation.
April 3, 2012

chemistry
The density of ethyl ether is 0.713g/ml would 536.8 g of this anesthetic fit into a 750.0ml flask?explain
February 28, 2012

biology
a) What type of bond is involved in complementary base pairing? -------------------------------------------------------- b) On what site of the large ribosomal subunit does the second tRNA attach during translation...
December 6, 2011

biology
1) What is the complementary strand of the DNA sequence GCAAT? a) GGCTT b) CGTTA c) CGTAT d) GCUUA
December 5, 2011

biology
which of the following represents the F1 generation of a monohybrid cross of YY x yy parents? a)100%Yy b)75%Yy:25%YY c)25%Yy:75%yy d)100%yy
November 30, 2011

biology
a disease caused by a bb gene is said to be?
November 30, 2011

chemistry
6). Which solution has the lowest pH? A) 1.3 X10–8 M –OH B) 1.0 X 10–7 M –OH C) 5.1 X10–5 M –OH D) 3.9 X 10–8 M –OH E) 2.3 X 10–3 M –OH
November 28, 2011

chemistry
7). The pH of a solution is 2.89. What is the [H3O+]? A) 1.3 X10–3 M H3O+ B) 1.3 X 1012 M H3O+ C) 7.9 X101 M H3O+ D) 7.9 X 10–13 M H3O+ E) 1.9 M H3O+
November 28, 2011

chemistry
8). What is the pH of a fruit with a [–OH] = 3.2  10–9 M –OH? A) 10.5 B) 8.49 C) 3.51 D) 3.5
November 28, 2011

chemistry
9). What is the balanced equation for the acid–base reaction of nitrous acid with lithium hydroxide? LiOH(aq) + HNO3(aq)  H2O(l) + LiNO3(aq) Li(OH)2(aq) + 2 HNO3(aq)  2 H2O(l) + Li(NO3)2(aq) LiOH(aq) + HNO2(aq)  H2O(l) + LiNO2(aq) 2 LiOH(aq) + ...
November 28, 2011

chemistry
10). What is the molarity of an HCl solution if 42.5 mL of a 0.110 M KOH solution is needed to titrate a 25.0-mL sample of the acid? A) 0.187 M HCl B) 0.587 M HCl C) 0.0647 M HCl D) 5.35 M HCl E) 1.70 M HCl
November 28, 2011

chemistry
The [H3O+] in a wine bottle is 3.1  10–2 M. What is the [–OH] in this wine?
November 28, 2011

chemistry
summarize the solubilty behavior of hydrocarbons in water (a polar solvent) and in non polar organic solvents
November 22, 2011

chemistry
write the equations for the substitution reaction of methene with bromine under the following conditions. a) reaction in the presence of sunlight CH4+Br2 sunlight=? b) reaction in the absence of sunlight CH4+Br2 =?
November 22, 2011

chemistry
write the equations for the addition reaction of ethene with bromine under the following conditions. a) reaction in the presence of sunlight H2C=CH2+Br2 sunlight=? b) reaction in the absence of sunlight H2C=CH2+Br2=?
November 22, 2011

chemistry
what gas is produced in the reaction between calcium carbide and water?write the balanced equation for the reaction.
November 22, 2011

chemistry
which solution has the lower pH? a)0.1 M HCL or 0.1 M HC2H3O2? b)0.1 M NaOH or 0.1 M NH3? c)0.1 M Na2CO3 or 0.1 M NaCl?
November 9, 2011

chemistry
DOES Mg(OH)2 HAVE A pH greater than 7 or less than 7
November 8, 2011

chemistry
DOES H3PO4 HAVE A pH greater than 7 or less than 7
November 8, 2011

chemistry
WHAT PROPERTY OF SOLUTION IS DESCRIBED BY ITS pH?
November 8, 2011

chemistry
what is the molarity of a solution prepared by dissolving 2.24 grams of NaOH in enough deionized water to obtain 500.0ml of solution?The molar mass of NaOH is 40.0g
October 31, 2011

chemistry
calculate the molarity of acetic acid in a vinegar sample,knowing that 5.00ml of vinegar requires 43.50ml of 0.105 M NaOH to just reach the phenolphthalein endpoint in a titration
October 31, 2011

chemistry
what is the molarity of a solution prepared by dissolving 2.24 grams of NaOH in enough deionized water to obtain 500.0ml of solution?The molar mass of NaOH is 40.0g
October 30, 2011

chemistry
calculate the molarity of acetic acid in a vinegar sample,knowing that 5.00ml of vinegar requires 43.50ml of 0.105 M NaOH to just reach the phenolphthalein endpoint in a titration
October 30, 2011

chemistry
write the balanced formula equation and the net ionic equation for the reaction of sodium hydroxide with hydrochloric acid. Formula equation.............. net equation.............
October 30, 2011

chemistry
How many grams of carbon disulfide,CS2 will form if 0.450 mol of carbon is consumed in a 3C+2SO2=CS2 +2CO2 reaction
October 16, 2011

chemistry
How many grams of carbon disulfide,CS2 will form if 0.450 mol of carbon is consumed in a 3C+2SO2=CS2 +2CO2 reaction
October 15, 2011

chemistry
show how CH4 +O2=CO2+H2O obeys the law of conservation of mass
October 15, 2011

chemistry
idont know theb answer
March 13, 2011

Statistics
company claims 10% are green. suppose that candies are packaged randomly into samll bags of 50. school children studying percent open several bags, count colors and find the proportion that are green. a. is the Normal model appropriate here? explain b. where is the center? ...
February 2, 2011

Math
What is the value of the expression below? 3•(-4)^2
November 8, 2010

10th grade
98 ???
September 20, 2010

10th grade
Evaluate u + xy, for u = 18, x = 10, and y = 8. a. 188 b. 224 c. 98 d. 36
September 20, 2010

science
conclusion
September 12, 2010

science
What is another word for conjecture? a. convention b. contrive c. converge d. conclusion
September 12, 2010

irish
please unsumble this (IBTGRGUAIRAMI)
November 19, 2008

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