Química preguntas y respuestas

1. Is the following sentence true or false? The new substances formed as a result of a chemical reaction are called products. 2. Circle the letter of each sentence that is a correct interpretation of the chemical equation \( \mathrm{C}+\mathrm{O}_{2} \longrightarrow \mathrm{CO}_{2} \). a. Carbon and oxygen react and form carbon monoxide. b. Carbon and oxygen react and form carbon dioxide. c. Carbon dioxide yields carbon and oxygen. d. The reaction of carbon and oxygen yields carbon dioxide. 3. Is the following sentence true or false? The law of conservation of mass states that mass is neither created nor destroyed in a chemical reaction.

Which of the following represents the sublevels from which the electrons are lost-when the atom of the element \( { }_{21} \mathrm{Sc} \) is converted to \( \mathbf{M}^{3+} \) ion ? \( \begin{array}{ll}\text { (i) } 3 s, 4 s & \\ \text { c) } 3 d, 4 p & \text { (d) } 4 s, 4 p\end{array} \)

2. Закончить уравнение химической реакции. Что является нуклеофилом в данной реакции? \( \mathrm{H}_{3} \mathrm{C}-\mathrm{O}-\mathrm{Na}+\mathrm{H}_{3} \mathrm{C}-\mathrm{CH}_{2}-\mathrm{I} \)

2. Закончить уравнение химической реа данной реакции? \( \mathrm{H}_{3} \mathrm{C}-\mathrm{O}^{-}-\mathrm{Na}+\mathrm{H}_{3} \mathrm{C}-\mathrm{CH}_{2}-\mathrm{I} \longrightarrow \)

При підвищенні тиску рівновага зміститься в бік утворення продуктів реакції \( \mathrm{H} 2(г)+\mathrm{Br} 2(г) \rightleftarrows 2 \mathrm{HBr}(г) \) \( \mathrm{C} 2 \mathrm{H} 6(г) \rightleftarrows \mathrm{C} 2 \mathrm{H} 4(г)+\mathrm{H} 2(г) \) \( 2 \mathrm{SO} 2(г)+\mathrm{O} 2(г) \rightleftarrows 2 \mathrm{OO} 3(г) \) \( 2 \mathrm{NH} 3(г) \rightleftarrows \mathrm{N} 2(г)+3 \mathrm{H} 2(г) \)

Domanda 4. Individuare la relazione matematica corretta tra le costanti di equilibrio \( K_{p} \) e \( K_{c} \) per la seguente reazione in equilibrio a una certa temperatura \( T \) : \[ \mathbf{C}_{(\mathbf{s})}+\mathbf{2} \mathbf{H}_{\mathbf{2 ( g )}} \leftrightarrows \mathbf{C H}_{\mathbf{4 ( g )}} \] a. \( K_{p}=K_{c} \)

\( Br _ { 120 } + H _ { 20 } \rightarrow \)

What is the correct number of significant figures in the number 0.0025060 ?

Duna quantità pari a \( 3,8 \mathrm{~mol} \) di un gas perfetto biatomico vene espansa a pressione costante \( p \). Il calore specifico a pressione costante è uguale a \( 2,0 \times 10^{3} \mathrm{~J} /(\mathrm{kg} \cdot \mathrm{K}) \). Calcola la massa di gas che viene espanso. \( [55 \mathrm{~g}] \)

Which element is diamagnetic? OF F Li Cd Ob