How many different types of toxins do molds make that can end up on our food and in our bodies?

A sample of CaCO3 (molar mass 100. g) was reported as being 30. percent Ca. Assuming no calcium was present in any impurities, c

natka813 [3]

Answer:

Approximately 75%.

Explanation:

Look up the relative atomic mass of Ca on a modern periodic table:

Ca: 40.078.

There are one mole of Ca atoms in each mole of CaCO₃ formula unit.

The mass of one mole of CaCO₃ is the same as the molar mass of this compound: $\rm 100\; g$ .
The mass of one mole of Ca atoms is (numerically) the same as the relative atomic mass of this element: $\rm 40.078\; g$ .

Calculate the mass ratio of Ca in a pure sample of CaCO₃:

$\displaystyle \frac{m(\mathrm{Ca})}{m\left(\mathrm{CaCO_3}\right)} = \frac{40.078}{100} \approx \frac{2}{5}$ .

Let the mass of the sample be 100 g. This sample of CaCO₃ contains 30% Ca by mass. In that 100 grams of this sample, there would be $\rm 30 \% \times 100\; g = 30\; g$ of Ca atoms. Assuming that the impurity does not contain any Ca. In other words, all these Ca atoms belong to CaCO₃. Apply the ratio $\displaystyle \frac{m(\mathrm{Ca})}{m\left(\mathrm{CaCO_3}\right)} \approx \frac{2}{5}$ :

$\begin{aligned} m\left(\mathrm{CaCO_3}\right) &= m(\mathrm{Ca})\left/\frac{m(\mathrm{Ca})}{m\left(\mathrm{CaCO_3}\right)}\right. \cr &\approx 30\; \rm g \left/ \frac{2}{5}\right. \cr &= 75\; \rm g \end{aligned}$ .

In other words, by these assumptions, 100 grams of this sample would contain 75 grams of CaCO₃. The percentage mass of CaCO₃ in this sample would thus be equal to:

$\displaystyle 100\%\times \frac{m\left(\mathrm{CaCO_3}\right)}{m(\text{sample})} = \frac{75}{100} = 75\%$ .

3 0

3 years ago

Iron and carbon:steel:copper and tin:___________

vesna_86 [32]

Answer:

iron and carbon:steel:copper and tin: metal

4 0

3 years ago

What does the size of the atom & their electron structure (called electron configuration) determine?

MAVERICK [17]

Answer:

In atomic physics and quantum chemistry, the electron configuration is the arrangement of electrons in an atom, molecule, or other physical structure (e.g., a crystal). ... The concept is also useful for describing the chemical bonds that hold atoms together.

Explanation:

hope this helps :)

8 0

3 years ago

What is gravity and weight please answer

gavmur [86]

Weight is the force of gravity on an object. Weight depends on the strength of the gravitational field the object is in and the mass of the object. ... Mass is constant anywhere in the universe, whereas weight depends on the gravity where the object is present (Earth, the moon, Jupiter, etc.).

3 0

3 years ago

Bowen's reaction series a. explains why some igneous rocks are phaneritic, and others aphanitic. b. shows that as magma crystall

Dominik [7]

Answer:

Option (D)

Explanation:

Bowen's reaction series usually represents the ranking of the mineral formation at different temperature conditions. There are two branches namely the continuous and the discontinuous branch.

The main objective of this series is to enable a viewer to understand at what temperature mineral forms, that give rise to the formation of igneous rocks.

It is very commonly used by the geologists and the mineralogists as it helps them in evaluating and predicting the order in which a particular type of mineral will form.

Thus, the correct answer is option (D).

7 0

3 years ago