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Which of these atoms has the largest number of neutrons in the nucleus? (a) <sup>148</sup>Eu (b) <sup>157</sup>Dy (c) <sup>149</sup>Nd (d) <sup>162</sup>Ho (e) <sup>159</sup>Gd
d,e
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1. Calculate the pH of the solution with (H<sup>+</sup>)= 1.0 x 10<sup>-3</sup> 2. Calculate the pH of the solution with (H<sup>+</sup>)= 3.6 x 10<sup>-5</sup>
pH= -log[H+]pH= -log[1×10^-3]pH= 32) pH= -log[3.6×10^-5]pH= 5-log3.6pH= 4.44
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What mass of liquid water can be heated from freezing to boiling with 42 kJ of energy, if the specific heat of water is 4.2 J g <sup>-1 </sup> <sup>o </sup>C <sup>-1 </sup>?
H= mcΔtm= H/cΔt= 42000/(4.2×100) = 100g
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What mass of liquid water can be heated from freezing to boiling with 42.6 kJ of energy, if the specific heat of water is 4.2 J g <sup>-1 </sup> <sup>o </sup>C <sup>-1 </sup>?
Freezing point of water = 0°CBoiling point of water = 100°CCwater = 4.2 Jg-1°C-1q = m × c × ∆T m = q/∆T × c= 42.6/(100-0) × 4.2= 0.01g
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If AgCN is added to water it found however, that 1 liter of solution contains x mole of AgCN, the solubility product is a) 4x<sup>3 </sup>b) x<sup>2</sup> c) x<sup>4</sup> d) 27x<sup>5</sup>
a) 4x3
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how to prepare a 5moldm<sup>-3</sup> HCl solution from 12moldm<sup>-3 </sup>and 2moldm<sup>-3 </sup>HCl solution
v=m/Mv(HCl)=5mol5mol=m/36.6g/molm=183gv(HCl)2=12+2=14molm(HCl)=14mol*36.6g/mol=512.4gw=183g/512.4g*100%=35.71%
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The pH of a 0.01M solution of a weak base is 10.65. What is the value of <i>K</i><sub><i>b</i></sub> for this base? 1)2.0 x 10<sup>-5</sup> 2)5.0 x 10<sup>-4</sup> 3)5.0 x 10<sup>-20</sup> 4)0.073
Kb-the degree of dissociation of the solution into ionsRight variant: 4
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<sup>?</sup><sub>?</sub>? +<sup>14</sup><sub>7</sub>N ⇒ <sup>17</sup><sub>8 </sub>O+ <sup>1</sup><sub>1</sub>H<sub> </sub>
147N+42He→178O+11H714N+24He→817O+11H is an example of a fission reaction
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Identify the 4 quantum numbers from the given electronic configurations a. 3p<sup>3</sup> b. 5p<sup>5</sup> c. 4s<sup>2</sup> d. 3p<sup>1</sup>
Energy (n), angular momentum (ℓ), magnetic moment (mℓ), and spin (ms).
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A container of 10 litres has a volume expressed in m<sup>3</sup> A. 1m<sup>3</sup> B. 0.01m<sup>3</sup> C. 0.001m<sup>3</sup> D. 0.0001m<sup>3</sup>
1 cubic metre =1000 litres10l = 1×10/1000 = 0.01B. 0.01m3
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