Consider the reaction represented \( \mathrm{byCr}_{2} \mathrm{O}_{7}^{2-}+\mathrm{Cl}^{-} \xrightarrow{\text { i. Explain why the reaction is a redox reaction. }} \quad \mathrm{Cr}^{3+}+\mathrm{Cl}_{2} \) iii. Balance the redox equation State five physical properties of metals

A partir de la siguiente ecuación de combustión de octano, si reaccionan 59.2 gramos de octano, ¿Cuántos gramos de Oxígeno se necesitan? \[ \mathrm{C}_{8} \mathrm{H}_{18}+25 / 2 \mathrm{O}_{2}-\cdots>8 \mathrm{CO}_{2}+9 \mathrm{H}_{2} \mathrm{O} \] Considera: \( \mathrm{C}: 12, \mathrm{O}: 16, \mathrm{H}: 1 \)

При образовании 2,2г СО \( { }_{2} \) по уравнению реакции: \( \mathrm{C}(\mathrm{тв})+\mathrm{O}_{2}=\mathrm{CO}_{2}(\mathrm{r}) \) выделилось 19,7 кДж теплоты. Стандартная энтальпия образования \( \mathrm{CO}_{2}(\mathrm{r}) \) в кДж/ моль равна -197 +394 +197 \( -394 \times \)

A chemist carefully measures the amount of heat needed to raise the temperature of a 510.0 mg sample of a pure substance from \( 2.9^{\circ} \mathrm{C} \) to \( 23.7^{\circ} \mathrm{C} \). The experiment shows that 25.9 J of heat are needed. What can the chemist report for the specific heat capacity of the substance? Be sure your answer has the correct number of significant digits.

A partir de la siguiente ecuación de combustión de octano, si reaccionan 59.2 gramos de octano, ¿Cuántos gramos de Oxígeno se necesitan? \[ \mathrm{C}_{8} \mathrm{H}_{18}+25 / 2 \mathrm{O}_{2}-->8 \mathrm{CO}_{2}+9 \mathrm{H}_{2} \mathrm{O} \] Considera: \( \mathrm{C}: 12, \mathrm{O}: 16, \mathrm{H}: 1 \)

A formula connecting density \( (d) \), mass \( (m) \) and volume \( (v) \) is \[ d=\frac{m}{v} \] \( m=30.14 \mathrm{~g} \) after being truncated to 2 d.p. \( v=3.78 \mathrm{~cm}^{3} \) after being truncated to 2 d.p. Calculate the lower and upper bounds of \( d \). Round your answers to \( 2 \mathrm{~d} . \mathrm{p} \).