Answer: Elements in Group 2
Explanation: The periodic table was arranged by Dmitri Mendeleev specifically around similarites in their chemical behaviors. He found that as atomic number increases, at some point an element starts to react in a manner similar to a previous one. When that happened, he would place the larger element under the smaller one, and eventually noticed a periodicity in the table. Elements in a column (Groups) had similiar chemical properties. We know today that these similarities are due to the electron configuration, and that these configurations repeat themselves. He left gaps in the table when he could find an existing element with properties similar to others in that group. I big leap of faith, but it worked. Elements for those missing boxes were eventually discovered.
Answer:
1. B, D,
2.A, F
Explanation:
1. According to the law of conservation of mass, In a course of chemical reaction, matter can neither be created nor destroyed but can be changed from one form to another. This means the amount of matter at the begining and ending of a reaction must be thesame.
2. Chemical reaction is not easily reversible. when gas is produced, provided the reaction system is an open system, the gas cannot be recovered and the reactants cannot be recovered from the products. likewise color change are attributed to chemical reaction
Answer:
When an animal breathes out, water vapor from inside the animal's lungs is released into the air.
Explanation:
The hydrologic cycle is the cycle of water movement throughout the environment. A is the only only one that "recycles" water;
4.1g
Explanation:
Given parameters:
Mass of carbon dioxide = 15g
Mass of oxygen gas = 11g
Unknown:
Mass of carbon consumed = ?
Solution:
Equation of the reaction:
C + O₂ → CO₂
To solve this problem from the balanced equation, we have to use the amount of product formed and work to Carbon. This is because, we are sure of the amount of carbon dioxide formed but the amount of the given oxygen gas used is not precise.
Number of moles of CO₂ = 
Molar mass of CO₂ = 12 + (16 x2) = 44g/mol
Number of moles of CO₂ = 
= 0.34mole
From the equation of the reaction;
1 mole of CO₂ is produced from 1 mole of C
0.34mole of CO₂ will produce 0.34mole of C
Mass of carbon reacting = number of moles x molar mass = 0.34 x 12 = 4.1g
Learn more:
Number of moles brainly.com/question/1841136
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