Hot, humid, close to the equator. Match the climate zone to the correct climate description

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

A horizontal row of elements in the periodic table represents a<br> group<br> period

castortr0y [4]

Answer:

Period

Explanation:

Periodic trend along period:

As we move from left to right across the periodic table the number of valance electrons in an atom increase. The atomic size tend to decrease in same period of periodic table because the electrons are added with in the same shell. When the electron are added, at the same time protons are also added in the nucleus. The positive charge is going to increase and this charge is greater in effect than the charge of electrons. This effect lead to the greater nuclear attraction.

The electrons are pull towards the nucleus and valance shell get closer to the nucleus. As a result of this greater nuclear attraction atomic radius decreases and ionization energy increases because it is very difficult to remove the electron from atom and more energy is required.The electron affinity also increases along period because of greater positive charge.

7 0

3 years ago

What material beats and lets you get though all of earth’s layers?

Goryan [66]

Seismic waves

Explanation:

Seismic waves are disturbances that transmits energy elastically and let's scientist have a glimpse of the interior of the earth.

These waves can pass through any component layer of the earth due to their unique properties.

There are four types of seismic waves but the two body waves are the most important in studying the earth's interior.

Seismic p-waves can pass through any earth materials as they are longitudinal waves.
Seismic s-waves are shear waves and can only pass through solids. liquids and gases cannot be sheared.

learn more:

Seismograph brainly.com/question/11292835

#learnwithBrainly

6 0

3 years ago

Balance this chemical reaction H2+N2–> NH3

GaryK [48]

Answer:

3H2+N2-> 2NH3

Explanation:

This is the balanced chemical equation for the above reaction

6 0

3 years ago

Determine how many moles of Ba(OH)2 are required to completely neutralize 0.427 mole of HC2H3O2.

Sergio039 [100]

.2135 mol of Ba(OH)2 are needed to neutralize .427 mol of 2HC2H3O2

4 0

3 years ago