Binary compounds of alkali metals and hydrogen react with...

Binary compounds of alkali metals and hydrogen react with water to liberate $\mathrm{H}_{2}(g) .$ The $\mathrm{H}_{2}$ from the reaction of a sample of $\mathrm{NaH}$ with an excess of water fills a volume of 0.490 $\mathrm{L}$ above the water. The temperature of the gas is $35^{\circ} \mathrm{C},$ and the total pressure is 758 $\mathrm{mm} \mathrm{Hg} .$ Determine the mass of $\mathrm{H}_{2}$ liberated and the mass of NaH that reacted.

Key Concepts

Stoichiometry of Chemical Reactions

Stoichiometry involves using a balanced chemical equation to determine the quantitative relationships between reactants and products. In this context, the reaction between an alkali metal hydride and water shows a one?to?one molar relationship between the hydride and hydrogen gas, allowing for direct conversion between moles of gas produced and moles of hydride consumed.

Ideal Gas Law

The Ideal Gas Law (PV = nRT) is used to relate the pressure, volume, temperature, and number of moles of a gas. It enables the calculation of the amount of gas (in moles) based on the measured volume under given conditions, forming the foundation for subsequent mass calculations.

Gas Collection Over Water

When gases are collected over water, the total measured pressure includes contributions from both the gas of interest and water vapor. Understanding this concept is crucial to correct the gas pressure by subtracting the vapor pressure of water at the given temperature to obtain the true pressure of the gas.

Molar Mass and Conversion

Molar mass is the mass per mole of a substance and is used to convert between the number of moles and the mass of a substance. This concept is essential in calculating the mass of hydrogen gas produced from the moles determined using the Ideal Gas Law, as well as determining the mass of the hydride that reacted based on its stoichiometric relationship.

Transcript

00:01 Hi guys, i'm here to serve question 124 of chapter 5.

00:07 So i'll read the question for binary compounds of acolymeta.

00:14 Hydrogen react with water to vibrate hydrogen gas.

00:21 The hydrogen from the reaction of sample of, well this is an example of the reaction.

00:30 This is acolymeter and hydrogen.

00:36 Battery component can be potassium hydride, lithium hydride, sodium hydride, that is binary compounds of acolymeter.

00:45 But in this case we are dealing with sodium hydride.

00:48 When it reacts with water, it forms hydrogen, gas.

01:00 This is the gas and it also formed some other product sodium hydroxide.

01:07 This is ecos.

01:09 Okay.

01:11 Whatever the case we look at this reaction the reaction is already in balance okay this is all we name now hydrogen from the reaction of a sample of sodium hydraide with excess of water we use excess of water so the relationship is between this and this that's our target so with excess water okay the hydrogen for feel a volume of 0 .49 later this is a volume of hydrogen for so volume of hydrogen we are dealing with hydrogen is volume equal to 0 .49 later at temperature of 35 degrees sizes and pressure of wood 758 millimeter of mercury now determine the mass of hydrogen gas.

02:28 I need the volume, but i need the mass of it is hydrogen gas.

02:36 I need the volume...

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