The number of protons in the nucleus of an atom is called its mass number valence isotope number atomic number none of these

Drag the tiles to the boxes to complete the pairs. Match the elements to their periodic table groups based on their uses or properties. \begin{array}{|c|c|} \hline\ Element\ is\ used\ as\ a\ disinfectant\ &\ \begin{array}{l}\ Element\ important\ for\ the\ proper\ \\ functioning\ of\ the\ human\ body. \end{array} \\ \hline Element always stored under oil. & \begin{array}{l}\ Compounds\ of\ this\ element\ are\ \\ used\ in\ manufacturing\ of\ paints. \end{array} \\ \hline group 3-12 & \\ \hline group 1 & \\ \hline group 17 & \\ \hline group 2 & \\ \hline \end{array}

6.2 g of an ionic compound is dissolved in a coffee-cup calorimeter containing 100.0 g of water at $16.2^{\circ }C$ The temperature of water increased to $19.5^{\circ }C$ What is the $\Delta H$ of the dissolution process in $kJ/mol$ of compound)? Assume that the specific heat of the solution is same as specific heat of water $(4.184$ $J/g^{\circ }C)$ The molar mass of the ionic compound is $72.1g/mol$

When $CuCl_{2}$ reacts with $NaNO_{3}$ , NaCl and $Cu(NO_{3})_{2}$ are produced as shown in the following balanced chemical equation. $CuCl_{2}+2NaNO_{3}\rightarrow 2NaCl+Cu(NO_{3})_{2}$ Suppose 19.35 g $CuCl_{2}$ reacts with 20.31 $NaNO_{3}$ Determine how many moles of $Cu(NO_{3})_{2}$ will be produced if 19.35 g $CuCl_{2}$ reacts with excess $NaNO_{3}$ The molar mass of $CuCl_{2}$ is $134.45g/mol$

Which of the following is a proper use for a calorimeter? Multiple Choice measuring heat of combustion measuring temperature of a mixture measuring the amount of oxygen consumed in a combustion reaction measuring entropy of a reaction

In the combustion of methane (balanced reaction shown below), what are acceptable ratios of methane to oxygen to ensure complete combustion? $CH_{4}+2O_{2}\rightarrow CO_{2}+2H_{2}O$ $1CH_{4}:4O_{2}$ $2CH_{4}:1O_{2}$ $1CH_{4}:3O_{2}$ C $1CH_{4}:1O_{2}$ $0.5CH_{4}:1O_{2}$

Atoms: The Building Blocks of Matter John has 1 mole of an element, but doesn't tell you what the element is. But you do know how many isotopes of the element he has. how much volume of the element he has. how many grams of the element he has. how many particles of the element he has.

$PCl_{5}$ can be produced by the reaction $PCl_{3}+Cl_{2}\rightarrow PCl_{5}$ What mass of $PCl_{3}$ must be used to produce 479.525 g of $PCl_{5}$ if the percent yield is $62.9\% $ $\square $

Some compounds have more than one Lewis dot structure. True False

Determine whether the sign of \$\Delta E\$ is positive or negative for each system. Drag the items into the appropriate bins. View Available Hint(s) \begin{array}{|l|l|l|} \hline\ \begin{array}{l}\ A\ draft\ is\ Paglimes\ \\ Bible\ for\ the\ \\ Reaganic \end{array} & \begin{array}{l}\ A\ detail\ and\ acid\ chemical\ mixture\ \\ is\ warmed\ with\ a\ hot\ plate.\ \\ (System:\ reaction\ mixture) \end{array} & \begin{array}{l}\ Ice\ in\ a\ glass\ of\ water\ melts,\ \\ cooling\ the\ water\ around\ it.\ \\ (System:\ melting\ ice) \end{array} \\ \hline Positive & & Negative \\ \hline \end{array}

What is the volume when $524cm3$ of a gas at 491 K is cooled to 297 K? 491 K is $T_{1}$ and $524cm3$ is $V_{1}$ What variable is $V_{2}$ ? unknown 297K $524cm^{3}$