4. How many moles of NaOH(s) would be required to react with 1.90 g of Cu(NO3)2 (aq) according to the balanced equation:
Cu(NO3)2(aq) + 2 NaOH(aq) → Cu(OH)2(s) + 2 NaNO3(aq)

2.03 x 10⁻² mol NaOH

Explanation:

First step for these questions is to ensure the reaction is balanced, then use the periodic table to determine the molar mass for the reactant you are given. Use the ratio from the balanced equation and dimensional analysis to solve. See attached image

i would say b

explanation:

but i think i would need more information than that

they it depends on if one believes about radioactivity, they make a geiger counter beep but maybe it was going to beep anyway electronics do wierd things all the time or it was programmed to beep near certain metals.