The following equation can be used to relate the density of liquid water to celsius temperature in the range from o°c to about 20°c, rho (g/cm3) = 0.99984 + (1.6945 x 10-2 t) – (7.987 x 10-6 t2)
1 + (1.6880 x 10-2 t)

(a) to four significant figures, determine the density of water at 10°c
(b) at what temperature does water have a density of 0.99860 g/cm3?

a) T = 10°C ⇒ ρ = 0.9997 g/cm³

b) ρ = 0.99860 g/cm³ ⇒ T = 16.7°C

Explanation:

∴ ρ = (0.99984 + (1.6945 E-2 T) - (7.987 E-6 T²))  / (1 + (1.6880 E-2 T))

a) T = 10 °C

⇒ ρ = (0.99984 + (1.6945 E-2(10)) - (7.987 E-6(10)²)) / (1 + (1.6880 E-2(10)))

⇒ ρ = (0.99984 + 0.16945 - 7.987 E-4) / ( 1 + 0.1688 )

⇒ ρ =  0.9997 g/cm³

b) ρ = 0.99860 g/cm³³

⇒ 0.99860m = (0.99984 + 1.6945 E-2T - 7.987 E-6T² ) / (1 + 1.6880 E-2 T)

⇒ 0.99860 * (1+ 1.6880 E-2T) = 0.99984 + 1.6945 E-2T - 7.987 E-6T²

⇒ 0.99860 + 0.016856T = 0.99984 + 1.6945 E-2T - 7.987 E-6T²

⇒ 7.987 E-6T² - 8.8632 E-5T - 1.24 E-3 = 0

⇒ T = 16.7°C

each  column  of the  table  is called a group. elements in a group share similar properties. groups are  read  from  top  to  bottom. metal. metalloid. nonmetal. solid. liquid. gas. fe. hg. o.  2. 3. 4. 5. 6. 7. 8. 9.  2. beryllium. 9.012. 4.  sodium. 22.990.  11. 3.  magnesium. 24.305.  12.  potassium. 39.098.  19. 4.  calcium. 40.078.  20. i guess  i  

atomic mass = 39

number of neutrons = 20

number of protons= 19

electronic configuration = 1s2 2s2 2p6 3s2 3p6 4s1

the number of electron in first shell = 2

number of electrons in n=3 shell = 8