Answer:
Mass = 11.78 g of P₄
Explanation:
The balance chemical equation is as follow:
6 Sr + P4 → 2 Sr₃P₂
Step 1: Calculate moles of Sr as;
Moles = Mass / M/Mass
Moles = 50.0 g / 87.62 g/mol
Moles = 0.570 moles
Step 2: Find moles of P₄ as;
According to equation,
6 moles of Sr reacted with = 1 mole of P₄
So,
0.570 moles of Sr will react with = X moles of P₄
Solving for X,
X = 1 mol × 0.570 mol / 6 mol
X = 0.0952 mol of P₄
Step 3: Calculate mass of P₄ as,
Mass = Moles × M.Mass
Mass = 0.0952 mol × 123.89 g/mol
Mass = 11.78 g of P₄
12gHe/1 × 1molHe/4.0026g × 6.02x10^23atomHe/1mol = 1.8 atoms
Answer:
Mutations can be caused by high-energy sources such as radiation or by chemicals in the environment. They can also appear spontaneously during the replication of DNA. Mutations generally fall into two types: point mutations and chromosomal aberrations. In point mutations, one base pair is changed. A single mutation can have a large effect, but in many cases, evolutionary change is based on the accumulation of many mutations with small effects. Mutational effects can be beneficial, harmful, or neutral, depending on their context or location. Most non-neutral mutations are deleterious.
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Answer:
D. Atoms are like solid balls
Explanation:
John Dalton proposed that all matter is composed of very small things which he called atoms. This was not a completely new concept as the ancient Greeks (notably Democritus) had proposed that all matter is composed of small, indivisible (cannot be divided) objects. When Dalton proposed his model electrons and the nucleus were unknown.
Answer: when reactants and products are gases at STP.
Justification:
1) STP stands for standard temperature (0°) and pressure (1 atm).
2) According to the kinetic molecular theory of the gases, and as per Avogadro's principle, equal volumes of gases, at the same temperature and pressure, have the same number of molecules.
3) Since the coefficients in a balanced chemical equation represent number of moles, when reactants and products are gases at the same temperature and pressure, the mole ratios are the same that the volume ratios, and then the coefficients of the chemical equation represent the volume ratios.
