En la ecuación al quedar balanceada, el coeficiente del agua es: \( \mathrm{KMnO}_{4}+\mathrm{NH}_{3} \xrightarrow{\mathrm{KNO}_{3}+\mathrm{MnO}_{2}+\mathrm{KOH}+\mathrm{H}_{2} \mathrm{O}} \) \( \begin{array}{llll}\text { a) } 2 & \text { b) } 3 & \text { c) } 8 & \text { d) } 5\end{array} \)

The half-life of radium is 1690 years. If 20 grams are present now, how much will be present in 100 years?

ALCANOS:ENLACES SIMPLE 1- 2,3 DIMETIL HEXANO 2- 2-ETIL 3.3- DIMETIL-5-ISOPROPIL-OCTANO 3- 3-METIL-2,6,7-TRIETIL-NONANO 4- 2-BUTIL-3,5,7-TRIMETIL- DECANO 5- 3-ETIL-5,7-DIMETIL-4-PROPIL-DODECANO

Balancea por óxido - reducción las ecuaciones siguientes: \( \begin{array}{l}\text { 1) } \mathrm{HNO}_{3}+\mathrm{S} \\ \begin{array}{l}\text { Semireacción de oxidación } \\ \text { Agente oxidante } \longrightarrow\end{array} \\ \mathrm{NO}_{2}+\end{array} \mathrm{H}_{2} \mathrm{SO}_{4}+\mathrm{H}_{2} \mathrm{O} \) \( \begin{array}{l}\text { Semireacción de reducción } \\ \text { Agente reductos }\end{array} \)

\( \mathrm{LiOH}+\mathrm{HBr} \rightarrow \mathrm{LiBr}+\mathrm{H}_{2} \mathrm{O} \) If you start with 10.0 grams of lithium hydroxide, how many grams of lithium bromide will be produced?

33. 15 g of magnesium ( Mg ) was reacted with 40 g of HCl to form magnesium chloride \( \left(\mathrm{MgCl}_{2}\right) \) and hydrogen gas as in the following reaction: \( \mathrm{Mg}(\mathrm{s})+2 \mathrm{HCl}(\mathrm{aq}) \rightarrow \mathrm{MgCl}_{2}(\mathrm{aq})+\mathrm{H}_{2}(\mathrm{~g}) \) Calculate the mass in gram \( (\mathrm{g}) \) of \( \mathrm{MgCl}_{2} \) formed \( \begin{array}{llll}\text { A) } 25.7 & \text { C) } 104.8 & 30.7 & \text { D) } 52.2\end{array} \)