Haha ironically I had this problem not too long ago, I hope by this we will both be better students. Everyone just needs practice. Ok stop to pep talk and lets go. I'll try to go step by step.
<span>So basically since this is a balanced equation, the ratios of mols of the elements are equal, atom wise. </span>
<span>So you notice they give you Br2 is 1.0 kg (1000g) and that means there are 2 mols of Br2. And its asking for Cl2, (on the left) it also has 2 mols. </span>
<span>Then you can start from 1000g Br2 and multiply with 2 mol Br2 and 159.8g Br2 on the bottom. The 159 8 is the actual grams per mol. Then when you write this down, continue multipying with the next fraction. </span>
<span>Since you know the molar mass of Cl2 is 70.4 and you know theres 2 mols, you can say that 2 mols of Br2 = 2 mols of Cl2 so you should be able to multiple 2 mol Br2 / 159.8g Br2 with 70.4 g Cl2 / 2 mol Cl2. Bam the mols cancel out and you have the grams for Cl2. Multiple all that out and you should get 443g Cl2. Notice how the beginning question gives 2 significant figures, so technically 440g Cl2 is more of an exact number.</span>
This is what is normally termed a single replacement reaction, although don't hold me to that. It could have changed to something more modern.
2 moles of water are produced. Here, hydrogen is the limiting reagent. 1 mole of oxygen is used up with 2 moles of hydrogen to form 2 moles of water. 1 moles of oxygen remains.
Reactivity is not a physical property because it's a characteristic of a chemical element or compound and is involved in chemical process.
