Answer:
52.08grams
Explanation:
Heat of fusion is the energy needed to transform solid water into liquid water. Hess's Law.
The temperature change Liquid water to Solid Ice. 20 degrees C --> 0 degrees C. is 20 degree C.
The heat needed for this is = 4.184 J/(g*C) * (36 grams of water) * 20 degrees C = 3012 joules of energy.
Liquid water to solid water.
Heat of fusion of water is 335j/g = 6.02kJ/mol
The heat needed for this is 6.02 kJ/mol * 2 moles of water = 12.04 kJ = 12040 joules of energy.
Adding the two energies, we have a total energy iof 15052 joules.
15052 joules = H(vap of CCl2F2) * grams of CCl2F2 needed = 289 J/g * x grams 15052 / 289 = 52.08 grams needed.
Answer:
Increase in the concentration of the reactants (vinegar and baking soda) leads to an increase in the rate of reaction (more volume of CO2 is evolved within a shorter time)
Explanation:
The chemical reaction between baking soda and vinegar in water is shown in the chemical reaction equation below;
NaHCO3(aq) + CH3COOH(aq) ----->CO2(g) + H2O(l) + CH3COONa(aq)
The chemical name of baking soda is sodium bicarbonate (NaHCO3) while vineager is a dilute acetic acid (CH3COOH) solution. This reaction provides a very easy set up in which we can study the effect of concentration on the rate of chemical reaction.
We must have it behind our minds that increase in the concentration of reactant species increases the rate of chemical reaction. Secondly, the rate of the reaction between baking soda and vinegar can be monitored by observing the volume of CO2 evolved and how quickly it evolves from the reaction mixture.
We can now postulate a hypothesis which states that; 'increase in the concentration of the reactants (vinegar and baking soda) leads to an increase in the rate of reaction (more volume of CO2 is evolved within a shorter time).'
If we go ahead to subject this hypothesis to experimental test, it will be confirmed to be true because a greater volume of CO2 will be evolved within a shorter time as the concentration of the reactants increases.
Just use a solubility chart! Find the cation on the far left and the anion on the top and find where they connect. If it says "s," it is not soluble. If it says "aq," it is soluble. Here, ZnF (Zinc Fluoride) is soluble. Hope that helps! :)
P.S. Not all of the compounds above are on this particular chart. In future problems, just google "solubility chart" until you find one with all of the compounds you need to look at.
About 255.3 grams is the answer I believe. I just had a school work packet and had that question on it, and that is the answer that I had put on it I believe.
Answer: Rhenium is used as an additive to tungsten- and molybdenum-based alloys to give useful properties. These alloys are used for oven filaments and x-ray machines. It is also used as an electrical contact material as it resists wear and withstands arc corrosion.
Explanation:
