13 gás hidrogênio reage com gás cloro produzin- do ácido clorídrico. Ao reagir 10 g de hidrogênio com 500 g de cloro, houve formação do produto ácido, mas observou-se que 145 g de cloro per- maneceram sem reagir. Qual será a massa, em gramas, do ácido clorídrico formado? Justifique

2. Determine el número de oxidación del elemento indicado en cada una de las sustancias siguientes: a) Ti en \( \mathrm{TiO}_{2} ; \) b) Sn en \( \mathrm{SnCl}_{4} ; \) c) C en \( \mathrm{C}_{2} \mathrm{O}_{4}^{2-} ; \) d) N en \( \left(\mathrm{NH}_{4}\right) \mathrm{SO}_{4} ; \) e) N en \( \mathrm{HNO}_{2} ; \) f) Cr en \( \mathrm{Cr}_{2} \mathrm{O}_{7}^{2-} \)

Question 12 (1 point) \( \begin{array}{l}\text { 4) Listen } \\ \text { Medium carbon steel has a carbon content of } 0.35 \% \text {. What is the fractional portion } \\ \text { of carbon in this steel? }\end{array} \).

All the following aims to get iron ore used in red pigments except: (Exam \( 1 \mathrm{L2} \mathbf{~ C h} 2 \) ) a) Thermal decomposition of iron salt produced from reacting diluted \( \mathrm{H}_{2} \mathrm{SO}_{4} \) with black iron oxide b) Heating of yellowish grey ore strongly in air c) heating Iron II hydroxide above \( 200^{\circ} \mathrm{C} \) d) Oxidation of black iron oxide

Question 13 (1 point) \( \begin{array}{l}\text { Hydrogen sulphide gas can be deadly when in concentrations above } 650 \text { PPM (parts } \\ \text { per million). Express this value as a percentage. }\end{array} \)

Upon thermal decomposition of X, a black compound was expected, but a red compound was found instead, what might be the reason? (Exam 1 L2 Ch2) a) condition of (absence of air ) was not properly applied b) the temperature applied was not sufficient c) the wrong compound was thermally decomposed instead of the correct one d) both a and c are correct