Answer:
62.98 % of the sample of hydrate is water
Explanation:
Step 1: Data given
Mass of the sample of a hydrate of sodium carbonate (Na2CO3) = 2.026 grams
After heating, the mass of the sample is 0.750 g
Molar mass H2O = 18.02 g/mol
Step 2: Calculate mass of water
Mass water = mass of hydrate - mass of sample after heating
Mass water = 2.026 grams - 0.750 grams
Mass water = 1.276 grams
Step 3: Calculate mass % percent of water
Mass % of water = (mass of water / total mass hydrate) * 100 %
Mass % of water = (1.276 grams / 2.026 grams) *100 %
Mass % of water = 62.98 %
62.98 % of the sample of hydrate is water
Answer:B) a reactant that undergoes reduction
Explanation:
Oxidation reaction is defined as the reaction in which a substance looses electrons. The oxidation state of the substance increases during oxidation.
Reduction reaction is defined as the reaction in which a substance gains electrons. The oxidation state of the substance gets reduced during reduction.
Overall reaction: 
The substance M which itself gets oxidized, reduces other and is called as reducing agent. The substance N which itself gets reduced, oxidizes other and is called as oxidizing agent.
First, we need the no.of moles of O2 = mass/molar mass of O2
= 55 g / 32 g/mol
= 1.72 mol
from the balanced equation of the reaction:
2H2 (g) + O2(g) → 2H2O(g)
we can see that the molar ratio between O2: H2O = 1: 2
So we can get the no.of moles of H2O = 2 * moles of O2
= 2 * 1.72 mol
= 3.44 mol
So by substitution by this value in ideal gas formula:
PV = nRT
when P = 12.4 atm & n H2O = 3.44 mol & R= 0.0821 & T = 85 + 273=358K
12.4 atm *V = 3.44 * 0.0821 * 358 = 8.15 L
∴ V ≈ 8.2 L
Silver is not a compound. It's a mixture
The knowledge of periodic table would be important in these three different careers such as medicine, pharmacology and engineering.
<h3>What is the importance of periodic table in following careers?</h3>
Periodic table is organised the whole elements vertically in groups and horizontally in periods with increasing atomic number.
The knowledge of arrangement of these elements serves alot of purposes in the following three different careers:
- Medicine: The element, iron is an important metal in the periodic table used in treatment of low blood levels.
- Pharmacology: The transition metals are useful in the field of pharmacology for the production of drugs. Example of such elements are chromium, manganese, cobalt, nickel, copper, and molybdenum.
- Engineering: The information of elements in the periodic table helps engineers in designing of materials used for constructions.
Therefore, the knowledge of periodic table is very important in these three different careers such as medicine, pharmacology and engineering.
Learn more about period table here:
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