Answer:
17 ppm
Explanation:
Paso 1: Información brindada
Masa de soluto: 0.025 g
Volumen de solución: 1.5 L
Paso 2: Convertir la masa de soluto a miligramos
Usaremos el factor de conversión 1 g = 10³ mg.
0.025 g × (10³ mg/1 g) = 25 mg
Paso 3: Calcular las partes por millon (ppm) del soluto
Usaremos la siguiente expresión.
ppm = mg de soluto / litros de solución
ppm = 25 mg / 1.5 L
ppm = 17 mg/L
M(KNO₃)=101.1 g/mol
M(CO(NH₂)₂)=60.1 g/mol
m(N)=M(N)m(KNO₃)/M(KNO₃)
m(N)=2M(N)m(CO(NH₂)₂)/M(CO(NH₂)₂)
2m(CO(NH₂)₂)/M(CO(NH₂)₂)=m(KNO₃)/M(KNO₃)
m(CO(NH₂)₂)=M(CO(NH₂)₂)m(KNO₃)/(2M(KNO₃))
m(CO(NH₂)₂)=60.1*101.1/(2*101.1)=30.05 g
Answer:
- <em>1. The mass of an atom is concentrated at the nucleus.</em>
<em />
- <em>3. Positive charge is condensed in one location within the atom.</em>
<em />
- <em>4. The majority of the space inside the atom is empty space.</em>
<em />
- <em>6. The atom contains a positively charged nucleus.</em>
Explanation:
When J.J Thmpson discovered the electron, he depicted the atom by the plum pudding model: a solid dough of homogeneously distributed positive charge (the pudding) containing negatively charged electrons (the plums).
Later, the scientist <em>Ernest Rutherford</em>, with its experiment of the gold foil experiment showed that the subatomic particles where not all concentrated in a solid part.
When a thin gold foil was bombarded with alpha particles (positively charged nuclei of helium atoms), most of the particles went through the gold sheet, with little deviation, but some particles bounded with a high deviation.
Such few high deviations were explained by the fact that there was a heavy region in the atom (the core or nucleus) with the positive charge that repelled the positively charged alpha particles.
Thus, <em>the mass of the atom was conentrated at the nucleus</em> (choice 1), where the positive charge is distributed in one location, which is the nucleus (not over the entire atom, just on the nucleus) discarding the choice number 2 (that a positive charge is spread equally over the atom) and proving choices 3 (<em>the positive charge is condensed in one location within the atom</em>) and 6 (<em>the atom contains a positively charged nucleus</em>).
Since most of the particles indeed went through the nucleus, this nucleus has to occupy little space, and most of the atom was empty space, proving choice 4 (<em>the majority of the space inside the atom is empty space</em>).
Answer:
Silicon does not form double bonds with oxygen, whereas carbon is capable of forming double bonds with oxygen. While the carbon dioxide molecular structure is linear, the silicon dioxide has an extended, different covalent structure.
Explanation:
If the sizes of the atoms of Silicon (Si) and Carbon (C) are compared to each other, the Si atoms are larger than carbon - which implies that the Si-O bonds will be longer than the C-O bonds. As a result, the p orbitals present on the Si and O atoms aren't very near to each other, in order to get together for the required overlap sideways which could have formed a stable pi bond. Hence, Silicon forms only single covalent bonds with Oxygen in silicon dioxide, in the form of a diamond structure with each Si atom being connected to its four neighbouring atoms through an O atom.
On the other hand, in the case of carbon dioxide, C is perfectly capable of forming double bonds with O. The different p orbitals are brought close together, resulting in a sideways overlap that leads to two pi bonds, twisted at a right angle to each other. As a result, the Carbon in carbon dioxide bonds with 2 oxygen atoms but not 4.
There are several reasons behind why they must keep accurate notes.
There may be a mistake or an anomaly that occurs during the process, and something completely different than the desired compound may be created and the process may need to be repeated.
The investigation may be successful and may need to be repeated.
The investigator may need to prove that the project was done by him and the notes may help him to do so. (hence why they must be dated and signed.)
The investigator may need them to protect him from legal action.
The pharmaceutical company may need proof that the possible medicine is safe and effective, and that it works as it should.