• Factorize 2520 and 6468 into prime factors, hence find their GCD.?

    Best answer: Since it is an even numbers divide by the first prime number Hence 2)2520 2)1260 2)630 2)315 Since it is no longer an even number, we try the next prime number ; '3' 3)315 3)105 5)35 Then '5' 7)7 = 1 When reduced to '1' we have all the factors. Hence 2520 = 2^4 X 3^2 x 5^1 x 7^1 Similarly for 6468... show more
    Best answer: Since it is an even numbers divide by the first prime number Hence 2)2520 2)1260 2)630 2)315 Since it is no longer an even number, we try the next prime number ; '3' 3)315 3)105 5)35 Then '5' 7)7 = 1 When reduced to '1' we have all the factors. Hence 2520 = 2^4 X 3^2 x 5^1 x 7^1 Similarly for 6468 2)6468 2)3234 3)1617 7)539 (NB '5' will not divide) 7)77 11)11 = 1 Hence 6468 = 2^2 x 3^1 x 7^2 x 11^1 Hence 2^2 x 3^1 x 7^1 is common to both 4 x 3 x 7 = 84 is the GCD
    6 answers · Mathematics · 3 days ago
  • Have you ever been out of your town?

    Best answer: YES!!!! I have been so far out as 12,000 miles ; the opposite side of the Earth.
    Best answer: YES!!!! I have been so far out as 12,000 miles ; the opposite side of the Earth.
    123 answers · Polls & Surveys · 6 days ago
  • Can i solve simultaneous equations using quadratic formula?

    Best answer: x^2 + y^2 = 20 y = 2 - 3x y^2 = (2 - 3x)^2 Substitute x^2 + ( 2 - 3x)^2 = 20 x^2 +(4 - 12x + 9x^2) = 20 10x^2 - 12x - 16 = 0 Agreed so far!!!! Factor '2' 2(5x^2 - 6x - 8) =0 This does Factor to (5x - 4)(x + 2) = 0 5x = 4 x = 4/5 = 0.8 & x = - 2 Are the two answers for 'x' However you can use the Quadratic... show more
    Best answer: x^2 + y^2 = 20 y = 2 - 3x y^2 = (2 - 3x)^2 Substitute x^2 + ( 2 - 3x)^2 = 20 x^2 +(4 - 12x + 9x^2) = 20 10x^2 - 12x - 16 = 0 Agreed so far!!!! Factor '2' 2(5x^2 - 6x - 8) =0 This does Factor to (5x - 4)(x + 2) = 0 5x = 4 x = 4/5 = 0.8 & x = - 2 Are the two answers for 'x' However you can use the Quadratic Eq'n to solve for any Quadratic, whether it is factorable or not!!!! Once you have the two values of 'x' , substitute into the lineareq'n for 'y' The two points represent the intercepts of a straight line with a circle. .
    6 answers · Mathematics · 1 week ago
  • If a salt is the main product of a neutralisation reaction, does that make “acid + metal” a neutralisation reaction?

    Best answer: NO !!!! Because the other product is hydrogen. Nutralisation reactions MUST produce water. Remember the general equations for reacting acids. Acid + Base = Salt + Water (neutralisation) Acid + Alkali = Salt + Water (neutralisation) Acid + Metal = Salt + Hydrogen (NOT neutralisation) Acid + Carbonate = Salt + Water + Carbon... show more
    Best answer: NO !!!! Because the other product is hydrogen. Nutralisation reactions MUST produce water. Remember the general equations for reacting acids. Acid + Base = Salt + Water (neutralisation) Acid + Alkali = Salt + Water (neutralisation) Acid + Metal = Salt + Hydrogen (NOT neutralisation) Acid + Carbonate = Salt + Water + Carbon Dioxide. (neutralisation)
    3 answers · Chemistry · 7 days ago
  • What time is it where you are?

    Best answer: I am in England and the time is 1212hrs ; 12:12pm
    Best answer: I am in England and the time is 1212hrs ; 12:12pm
    11 answers · Geography · 1 week ago
  • 18) It takes 1.3×106 J of heat to bring a quantity of water from 13 ∘C to a boil.?

    Best answer: Use the equation Q = mcDeltaT Q = 1.3 x 10^6 J m = to be found c = specific heat of water 4.12 DeltaT - temperature difference ( 100 - 13 = 87) Substituting 1.3 x 10^6 = m X 4.12 x 87 m(g) = 1.3 x 10^6 / (4.12 x 87) m(g) = 3626.82 g = 3.626 kg ( volume would be 3.626 dm^3 (litre).
    Best answer: Use the equation Q = mcDeltaT Q = 1.3 x 10^6 J m = to be found c = specific heat of water 4.12 DeltaT - temperature difference ( 100 - 13 = 87) Substituting 1.3 x 10^6 = m X 4.12 x 87 m(g) = 1.3 x 10^6 / (4.12 x 87) m(g) = 3626.82 g = 3.626 kg ( volume would be 3.626 dm^3 (litre).
    2 answers · Chemistry · 1 week ago
  • Which one of the following should have the lowest boiling point? Ne H2O LiBr NF3 C2H5COOH?

    Best answer: 'Ne' Neon ; the boiling point is -245 degrees F or 27.05 K
    Best answer: 'Ne' Neon ; the boiling point is -245 degrees F or 27.05 K
    2 answers · Chemistry · 2 months ago
  • Which of these phase changes is an endothermic process? A: freezing B: condensation C: evaporation D: All phase changes are endothermic?

    Best answer: C is 'Endothermic' because the liquid is taking in (absorbing) heat in order to become a vapour . A & B are 'Exothermic' 'D' is a nonsense because a phase change from solid to liquid to gas is Endothermic., but a phase change from gas to liquid to solid is Exothermic. So not all phase changes are endithermic.... show more
    Best answer: C is 'Endothermic' because the liquid is taking in (absorbing) heat in order to become a vapour . A & B are 'Exothermic' 'D' is a nonsense because a phase change from solid to liquid to gas is Endothermic., but a phase change from gas to liquid to solid is Exothermic. So not all phase changes are endithermic. NB Remember if it is cooling it is Exothermic. If it is heating it is Endotermic. NNB 'Thermic' means 'Heat'. 'Exo/Endo' means 'Out of / Into ' respectively.
    2 answers · Homework Help · 2 weeks ago
  • What happens to a catalyst during a reaction?

    Best answer: Nothing!!!! A catalyst is a substance that 'Speeds up the rate of reaction'. At the beginning and end of a reaction the catalyst will be the same substance. However during a reaction a catalyst may change its oxidation state. In the Contact Process for making sulphuric acid, vanadium is used to catalyse the reaction between... show more
    Best answer: Nothing!!!! A catalyst is a substance that 'Speeds up the rate of reaction'. At the beginning and end of a reaction the catalyst will be the same substance. However during a reaction a catalyst may change its oxidation state. In the Contact Process for making sulphuric acid, vanadium is used to catalyse the reaction between sulphur dioxide and oxygen to make sulphur trioxide. Vanadium changes its oxidation state during the reaction.
    3 answers · Chemistry · 2 weeks ago
  • Chem Lab HELP?

    Best answer: Using the molar amounts O = 0.4844 / 16 = 0.030275 > 0/030275 / 0.009635 = 3.14 ~ 3 KCl = 0.7178 / (39 + 35.5) = 0.009635/ 0.009635 = 1 Hence O : KCl :: 3 : 1 KClOx is KClO3 NB Since oxygen is combined in the molecule it must be treated as 'O' .; NOT 'O2' It is nly when it is a 'free' gas it is... show more
    Best answer: Using the molar amounts O = 0.4844 / 16 = 0.030275 > 0/030275 / 0.009635 = 3.14 ~ 3 KCl = 0.7178 / (39 + 35.5) = 0.009635/ 0.009635 = 1 Hence O : KCl :: 3 : 1 KClOx is KClO3 NB Since oxygen is combined in the molecule it must be treated as 'O' .; NOT 'O2' It is nly when it is a 'free' gas it is diatomic. (O2) Hence KClO3 = KCl + (3/2)O2 2KClO3 = 2KCl + 3O2
    1 answer · Chemistry · 2 weeks ago
  • Why do we replace a proportionality sign with an equal sign and a constant?

    Best answer: You calculate the Constant of proportionality (k) from two terms that relate in a given system. It is so that in the same system any other term can be related to an unknown term . Hence A is directly proportional to B Then A = k X B A = kB k = A/B For inverse proportion A is inversely proportional to B A is proportional to... show more
    Best answer: You calculate the Constant of proportionality (k) from two terms that relate in a given system. It is so that in the same system any other term can be related to an unknown term . Hence A is directly proportional to B Then A = k X B A = kB k = A/B For inverse proportion A is inversely proportional to B A is proportional to 1/B A = k X 1/B A = k/B k = AB The classic Constant of Proportionality is 'pi' ( 3.141592.....) We can say Circumference (C) is directly proportional to the diameter (d) (C) is directly proportional to the (d) C = k X d C = kd k = C/d Historically , it was found that when the circumference of any circle was divided by its diameter it always resulted in 3.141592... (pi) So for circles the 'k' is replaced by 'pi' Hence C = pi d NB 'pi' is an 'Irrational' number ; the decimals go to infinity and are in no regular order. However, for schoolwork use 3.14 or 3.1416 which are approximations. Hope that helps!!!!
    2 answers · Homework Help · 2 weeks ago
  • What us the term for what conitent you re from?

    Best answer: No such term in the English language. However, by a language invention, you could say 'What is your continentality'.
    Best answer: No such term in the English language. However, by a language invention, you could say 'What is your continentality'.
    10 answers · Geography · 1 month ago
  • HELP !! CHEMISTRY Question??

    Best answer: When dding 0.002 mol (OH-) you are reducing the moles of formic acid by 0.1 - 0.002 = 0.098 as OH- add to H+ (of Formic Acid) to create water molecules. Since the formic acid is losing an H+ you are creating more formate. . Hene 01 + 0.002 = 0.102 of formate is produced. Ka = [H+][HCOO-] / [HCOOH] Algebraically rearrange [H+] =... show more
    Best answer: When dding 0.002 mol (OH-) you are reducing the moles of formic acid by 0.1 - 0.002 = 0.098 as OH- add to H+ (of Formic Acid) to create water molecules. Since the formic acid is losing an H+ you are creating more formate. . Hene 01 + 0.002 = 0.102 of formate is produced. Ka = [H+][HCOO-] / [HCOOH] Algebraically rearrange [H+] = Ka[HCOOH] / [HCOO-] [H+] = 1.8 x 10^-4 x 0.098 / 0.102 [H+] = 1.729 x 10^-4 pH = -log(10) [ H+] pH = -log(10) [1.729x 10^-4] pH = -(-3.762101) pH = 3.76 NB pH is always quoted to 2.d.p. NNB the modern IUPAC name for formic acid is 'Methanoic Acid'.
    1 answer · Chemistry · 2 weeks ago
  • A buffer consists of 0.20 M HC2H3O2 and 0.20 M NaC2H3O2. (pKa=4.74). What is the pH of this buffer after the addition of 0.020 mol of HCL?

    Best answer: pKa = 4.74 Hence Ka = 10^(-4.74) = 1.8197 x 10^-5 On adding H+(HCl) you are creating more HC2H3O2 and reducing C2H3O2^- Hence moles HC2H3O2 is 0.2 + 0.02 = 0.22 moles C2H3O2^- is 0.2 - 0.02 = 0.18 Hence Ka = [H+][A- ] / [HA] [H+] = Ka[HA] / [A-] [H+] = 1.8197 x 0^-5 x 0.22/ 0.18 [H+] = 2.0218898 x 10^-5 pH = -log(10) [H+] pH... show more
    Best answer: pKa = 4.74 Hence Ka = 10^(-4.74) = 1.8197 x 10^-5 On adding H+(HCl) you are creating more HC2H3O2 and reducing C2H3O2^- Hence moles HC2H3O2 is 0.2 + 0.02 = 0.22 moles C2H3O2^- is 0.2 - 0.02 = 0.18 Hence Ka = [H+][A- ] / [HA] [H+] = Ka[HA] / [A-] [H+] = 1.8197 x 0^-5 x 0.22/ 0.18 [H+] = 2.0218898 x 10^-5 pH = -log(10) [H+] pH = -log(10) [2.0218898 x 10^-5 ] pH = -(-4.694242509) pH = 4.69 ( to 2 d.p.) NB Organic acids and the anions are always written as ' CH3COOH' & (CH3COO-) Ethanoic acid & Ethanoate respectively.
    1 answer · Chemistry · 2 weeks ago
  • Can you answer these questions about acid rain?

    Best answer: a) Acids have loads of hydrogen ions present , symbolised as 'H^+' . b) pH means the 'negative logarithm to the base 10 of the hydrogen ion concentration'. c. pH scale ; Strong acid, weak acid, neutrality , weak base , strong base, corresponding numbers 1 - 14 , corresponding colours red(1), orange(3), yellow(5),... show more
    Best answer: a) Acids have loads of hydrogen ions present , symbolised as 'H^+' . b) pH means the 'negative logarithm to the base 10 of the hydrogen ion concentration'. c. pH scale ; Strong acid, weak acid, neutrality , weak base , strong base, corresponding numbers 1 - 14 , corresponding colours red(1), orange(3), yellow(5), green(7), blue(9), purple(11) violet(13) d) neutralisation reaction is an acid and a base/akalir reacting to form a salt & water. e.g. Hydrochloric Acid, Sodium Hysroxide gives sodium chloride and water. HCl + NaOH = NaCl + H2O
    2 answers · Chemistry · 2 weeks ago
  • The pH of a solution of an unknown, weak acid is 2.15. If the concentration of the acid is 1.25 M, what is the Ka for this acid?

    Best answer: [H+] = 10^(-pH) [H+] = 10^(-2.15) [H+]^2 = 10^(-4.30) Ka = [H^+][A^-] / [HA] Sincw HA dissociates to equal molar amounts o H^+ & A^- . Then we can substitute A^- for H^+ . Hence [H^+]^2 Ka = [H^+]^2 / [HA] Ka = 10^(-4.3) / 1.25 Ka = (7.079... x 10^-3) ^2 / 1.25 Ka = 5.0118 x 10^-5 / 1.25 Ka = 4.009 x 10^-5 Ka = show more
    Best answer: [H+] = 10^(-pH) [H+] = 10^(-2.15) [H+]^2 = 10^(-4.30) Ka = [H^+][A^-] / [HA] Sincw HA dissociates to equal molar amounts o H^+ & A^- . Then we can substitute A^- for H^+ . Hence [H^+]^2 Ka = [H^+]^2 / [HA] Ka = 10^(-4.3) / 1.25 Ka = (7.079... x 10^-3) ^2 / 1.25 Ka = 5.0118 x 10^-5 / 1.25 Ka = 4.009 x 10^-5 Ka =
    2 answers · Chemistry · 2 weeks ago
  • Math help please:?

    Best answer: a) f(0) = 1000(1.04)^0 = 1000(1) = 1000 f(10) = 1000(1.04)^10 = 1000(1.480244285) = 1480.244285 f(0) is the initial population f(10) is the population after 10 years.
    Best answer: a) f(0) = 1000(1.04)^0 = 1000(1) = 1000 f(10) = 1000(1.04)^10 = 1000(1.480244285) = 1480.244285 f(0) is the initial population f(10) is the population after 10 years.
    2 answers · Mathematics · 3 weeks ago
  • I have an lab in my class, and i would like to know how to separate two mixtures of solid one is soluble in water and the next one isn't?

    Best answer: Put the mixture in water, and allow the soluble substance to dissolve into the water. Then filter to remove the solid, which will be left in the filter paper. The solution should then be boiled/evaporated to gain the other soluble solid. .
    Best answer: Put the mixture in water, and allow the soluble substance to dissolve into the water. Then filter to remove the solid, which will be left in the filter paper. The solution should then be boiled/evaporated to gain the other soluble solid. .
    2 answers · Chemistry · 3 weeks ago
  • Chemistry help!!!!!!!!!!!?

    Best answer: You have the correct BALANCED equation CaCO3(s) = CaO(s)+ CO2(g) The molar ratios are 1::1:1 Next calculate the Mr(Relative Molecular Mass) from the PeriodicTable. Ca x 1 = 40 x 1 = 40 C x 1 = 12 x 1 = 12 O x 3 = 16 x 3 = 48 40 + 12 + 48 = 100 Using the Equation moles = mass(g) / Mr Hence mol(CaCO3) = 8.13 x 10^-6 / 100 =... show more
    Best answer: You have the correct BALANCED equation CaCO3(s) = CaO(s)+ CO2(g) The molar ratios are 1::1:1 Next calculate the Mr(Relative Molecular Mass) from the PeriodicTable. Ca x 1 = 40 x 1 = 40 C x 1 = 12 x 1 = 12 O x 3 = 16 x 3 = 48 40 + 12 + 48 = 100 Using the Equation moles = mass(g) / Mr Hence mol(CaCO3) = 8.13 x 10^-6 / 100 = 8.13 x10^-8 moles ( Equivalent to '1'(One) molar ratio). Since the molar ratios, above, are all '1' Then By equivalence moles of CO2 released is 8.13 x 10^-8 Next remember the Avogadro number, 6.022 x 10^23 is the number of molecules in one mole. So the number of molecules in 8.13 x 10^-8 moles is 8.13 x 10^-8 x 6.022 x 10^23 = 4.89 x 10^16 ( 48,900,000,000,000,000.0). (Forty Eight thousand nine hundred trillion).
    1 answer · Chemistry · 4 weeks ago
  • If f(x)=a^x; Show that: 1. f(u+v)=f(u)f(v) 2. f(2x)=[f(x)]^2?

    Best answer: f(u+v) = a^(u+v) a^(u+v) = a^(u) X a^(v) a^u = f(u) a^v = f(v) Hence F(u+v) = f(u)f(v) Similarly f(2x) = f(x + x) Hence a^(x + x) = a^x * a^x = (a^x)^2 Hence f(2x) = (a^x)^2 = [f(x)]^2
    Best answer: f(u+v) = a^(u+v) a^(u+v) = a^(u) X a^(v) a^u = f(u) a^v = f(v) Hence F(u+v) = f(u)f(v) Similarly f(2x) = f(x + x) Hence a^(x + x) = a^x * a^x = (a^x)^2 Hence f(2x) = (a^x)^2 = [f(x)]^2
    4 answers · Mathematics · 4 weeks ago