Answer:
A silicon atom has 14 electrons around the nucleus, and of these, there are 4 valence electrons on the outermost orbital. When this is made into a single crystal, it can be used as a material for semiconductor products. When it crystalizes, the nuclei share electrons and they bond with 8 electrons around each nucleus.
<span>H-1 means that the isotope has mass number 1: it has 1 proton. H-2 means that the isotope has mass number 2: so it has 1 proton and 1 neutron. H-3 means the isotope has 1 proton and 1 neutron. As you see all the isotopes have the same number of protons (atomic number), therefore they also have the same number of electrons. What defines (differentiate) isotopes is the number of electrons. So, fill the table such that the number of protons and electrons is 1 for all the isotopes, and the number of neutrons are 0 for H-1, 1 for H-2, and 2 for H-3.</span>
Answer: 0.125moles
Explanation:
From the question above, we are only given the values of the volume and molar concentration of CuSO4 solution.
Volume of CuSO4 solution = 250mL= 250/1000L = 0.25L
Molar concentration of CuSO4 solution= 0.50M
Number of moles of CuSO4= Molar concentration of CuSO4 × volume of CuSO4
Number of moles of CuSO4= 0.50mol/dm^3 × 0.25L
Number of moles of CuSO4= 0.125moles
Therefore 0.125moles of CuSO4 are used to make 250 mL of a 0.50M CuSO4 solution.
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Answer
The four steps of the scientific method are:
1) Observation and description of a natural phenomenon of group of phenomena;
2) Formulation of a hypothesis to explain the phenomena;
3) Use of the hypothesis to predict the existence of other phenomena or to predict quantitatively the results of new observations, i.e to test the hypothesis if the hypothesis is true, find more evidence or find counter-evidence, if the hypothesis is false, create a new hypothesis or try again; and
4) Draw conclusions and repeat –the scientific method is never-ending, and no result is ever considered perfect.