Achemist measured 5.2 g copper(ii) bromide tetrahydrate (cubr2•4( how many moles were measured out? answer in units of mole.

Explanation:

The first step is to find the weight per mol of (CuBr2•4(H2O))

We can do this replacing the elements Cu,Br,H,O by their respectively molar masses.

The molar mass of an element represents its weight per mole of element.

For the elements :

Replacing this values in the copper(II) bromide tetrahydrate equation

(CuBr2•4(H2O)) ⇒

We find that a mole of copper(II) bromide tetrahydrate has a mass of 295.41272 g.

Given that we have 5.2 g in the sample, we can calculate the total moles as :

Solving for x :

A total of were measured.

your answer is a. the enthalpy of formation for a pure element in its standard state is always positive.