answer:Formaldehyde (37%) generally does not need to be stored at 5 degrees Celsius or below. Storing it at lower temperatures might cause paraformaldehyde (a formaldehyde polymer) or trioxymethane (a cyclic condensation product) to precipitate. However, this can be prevented or minimized by the presence of methanol, typically around 10 to 15%, which is added to inhibit polymerization. Unless specifically required for a particular application, storing formaldehyde solution at room temperature is sufficient and will not damage the solution.

answer:1. **Balanced Chemical Equation:** Cu(s) + 2AgNO_3(aq) to Cu(NO_3)_2(aq) + 2Ag(s) 2. **Total Ionic Equation:** To obtain the total ionic equation, we need to separate the soluble ionic compounds into their respective ions. In this case, (AgNO_3) and (Cu(NO_3)_2) are soluble in water and dissociate into ions. Cu(s) + 2Ag^+(aq) + 2NO_3^-(aq) to Cu^{2+}(aq) + 2NO_3^-(aq) + 2Ag(s) 3. **Net Ionic Equation:** The net ionic equation is obtained by removing the spectator ions, which are ions that appear on both sides of the equation and do not participate in the chemical reaction. In this case, (NO_3^-) is the spectator ion. Cu(s) + 2Ag^+(aq) to Cu^{2+}(aq) + 2Ag(s) Therefore, the net ionic equation for the given reaction is: Cu(s) + 2Ag^+(aq) to Cu^{2+}(aq) + 2Ag(s) The net ionic equation for the given reaction is: Cu(s) + 2Ag^+(aq) to Cu^{2+}(aq) + 2Ag(s)

answer:To find the sum of the two polynomials, we combine like terms: [ p(x) + q(x) = (-9x^2) + (2x) + (-14) + (-9x^2) + (-9x) + (-7) ] Combine the x^2 terms: [ -9x^2 - 9x^2 = -18x^2 ] Combine the x terms: [ 2x - 9x = -7x ] Combine the constant terms: [ -14 - 7 = -21 ] So the sum is: [ p(x) + q(x) = -18x^2 - 7x - 21 ]

answer:The least squares vector b can be calculated as follows: b = (A^T A)^{-1} A^T y After performing the matrix operations, we find that: b = left( begin{array}{c} -0.923 1.061 -0.066 0.352 end{array} right)