Answer:
3.75 g/mL
Explanation:
Density can be calculated using the following formula:
Density = mass (g) / volume (mL)
You have been given the mass of the mineral sample (75 g). To find the volume, you need to determine the amount of space that the sample takes up when it is placed in the water. This can be done by subtracting the initial water volume from the final water volume.
Volume = Final - Initial
Volume = 40 mL - 20 mL
Volume = 20 mL
Now, you can calculate the density of the mineral sample.
Density = mass / volume
Density = 75 g / 20 mL
Density = 3.75 g/mL
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Answer:
D) Tetrahedral
Explanation:
Hello,
Tetrahedral is a molecular shape that turns out when four bonds and no lone pairs around the central atom in the molecule. The bonded atoms to the central atom lie at the corners of a tetrahedron with 109.5° angles between them. The molecules with an tetrahedral electron pair geometries have
hybridization at the central atom. For instance, both ammonium ion (
) and methane (
) have a tetrahedral molecular geometry.
Best regards.
Models are usually approximations, too simple and sometimes unrealistic.
Explanation:
A model is an abstraction of the real world. Models are used by scientists to mimic and gain better insights into how the real world looks like to a greater degree of accuracy. Here are some set backs of models;
- Limitations due to parameters that can be modeled; it is nearly impossible to incorporate all the elements of the real world into a model. A scientist may have limited resources to integrate different data sets to perfectly have a good picture of the real world.
- Models are approximations: the fact that models are not exact can be worrisome. Questions like to what extent are these scenarios rounded can be very difficult to come by with and this can spoil a good research.
- Over simplicity: most times when a model proves too complex to work with, some parameters are left out and this can cause a good model to be watered and not portray the real world at all.
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*Necessary Information for the calculations*
Molar mass of carbon - 12.011 g/mol
Molar mass of copper - 63.546 g/mol
Molar mass of molecular oxygen - 31.998 g/mol
Avogadro's number - 6.022 x 10^23 atoms/mol
1. Moles of carbon in 19.2 grams of carbon (C)
To determine the number of moles carbon for a given mass of the substance, the mass of the sample is simply divided by its molar mass. Thus,
19.2 g C x <span><span> <u> 1 mol C </u></span><u> </u></span> = 1.599 mol C
12.011 g C
<span>
</span>2. Atoms of copper in 11.4 moles of copper (Cu)
To determine the number of atoms of a substance for a given number of moles, the latter is simply multiplied by Avogadro's number which represents the number of particles, molecules, or atoms of a any substance in 1 mole. Thus,
11.4 mol Cu x <u> 6.022x10^23 atoms Cu </u> = 6.865x10^24 atoms Cu
1 mole Cu
3. Mass of 3.15 moles of molecular oxygen (O2)
To determine the mass of a given number of moles of a substance, the former is simply multiplied by the molar mass of the substance. Thus,
3.15 mol O2 x <u> 31.998 g O2 </u> = 100.794 g O2
1 mole O2
4. Moles of silver in 6.51x10^24 moles of silver (Ag)
To determine the number of moles of a substance for a given number of atoms, the latter is simply divided by Avogadro's number. Thus,
6.51x10^24 atoms Ag x <u> 1 mol Ag </u> = 10.810 mol Ag
6.022x10^23 atoms Cu