Answer:
0.02 M
Explanation:
Given data:
Mass of sodium carbonate = 1.8 g
Volume of water = 862 cm³ (862/1000 = 0.862 L)
Concentration = ?
Solution:
Formula:
Concentration = number of moles / volume in L
Number of moles of sodium carbonate:
Number of moles = mass/molar mass
Number of moles = 1.8 g/ 106 g/mol
Number of moles = 0.02 mol
Concentration:
c = 0.02 mol / 0.862 L
c = 0.02 M
Answer: Sugar
Explanation: Because after photosynthesis (Carbon dioxide, water, and sunlight) react, they make two products. Glucose (A sugar) and Oxygen.
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Here, the magnification will be 2. Therefore, the height of the image will be twice the height of the object, which is, 4*2= 8 cm.</span>
We have to calculate the percentage (by mass) of Ba in the mixture of BaBr₂ and inert material.
Given, bromide ion is precipitated as AgBr by the addition of an excess of silver nitrate as per following reaction:
BaBr₂(aq) + 2AgNO₃(aq)→2AgBr(s)+Ba(NO₃)₂(aq). From this balanced chemical reaction, it is clear that one mole BaBr₂ reacts with two moles of AgNO₃ and gives two moles of AgBr. We have to calculate 0.6226 g AgBr contains how many moles of AgBr. Using that information we can get how many moles of BaBr₂ reacted to give 0.6226g AgBr and one mole BaBr₂ contains one mole of Ba. By multiplying number of moles of Ba with atomic mass of Ba we can get amount of Ba present in the mixture. Accordingly we can calculate mass percentage of Ba in the mixture.
Atomic mass of Ba= 137.327 g.mol, Molecular mass of BaBr₂=297.1 g/mol and molecular mass of AgBr=187.7 g/mol. Mass of AgBr is 0.6226 g which contains 0.6226/187.7 mole= 3.31X10⁻³ moles of AgBr. So, moles of BaBr₂ reacts= (3.31X10⁻³)/2 moles= 1.65X10⁻³ moles. One mole BaBr₂ contains one mole of Ba. So, 1.65X10⁻³ moles of BaBr₂ contains 1.65X10⁻³ moles of Ba atoms whose mass is=1.65X10⁻³X137.327g=0.2265 g. Out of 0.7207 g sample amount of Ba present is 0.2265 g. So, mass percentage is
=31.42 %
.
Universe grows and cools until 100 seconds after the Big Bang. The temperature is 1 billion degrees, 109 K. Electrons and positrons annihilate to make more photons, while protons and neutrons combine to make deuterons. Almost all of the deuterons combine to make helium.
Hope this helped.