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3 years ago

If the trend in a property is periodic, it means it will

Chemistry

1 answer:

kotegsom [21]3 years ago

8 0

Answer:

d) repeat

Explanation:

If the trend in a property is periodic, it means it will repeat on the periodic table.

Periodic properties on the table have a constant pattern as we move up or down a group or across a period from left to right.

This helps to predict some of the salient properties of elements as we move through the periodic table.
For example, on most periodic groups, metallicity increases as we move down the group and it decreases across the period.

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When calcium carbonate is added to hydrochloric acid, calcium chloride, carbon dioxide, and water are produced.

sp2606 [1]

Answer:

Mass of CaCl₂ = 20 g

CaCO is presewnt in excess.

Mass of of CaCO₃ remain unreacted = 7.007 g

Explanation:

Given data:

Mass of calcium carbonate = 25 g

Mass of hydrochloric acid = 13.0 g

Mass of calcium chloride produced = ?

Chemical equation:

CaCO₃ + 2HCl → CaCl₂ + H₂O + CO₂

Number of moles of CaCO₃:

Number of moles of CaCO₃ = Mass /molar mass

Number of moles of CaCO₃= 25.0 g / 100.1 g/mol

Number of moles of CaCO₃ = 0.25 mol

Number of moles of HCl:

Number of moles of HCl = Mass /molar mass

Number of moles of HCl = 13.0 g / 36.5 g/mol

Number of moles of HCl = 0.36 mol

Now we will compare the moles of CaCl₂ with HCl and CaCO₃ .

CaCO₃ : CaCl₂

1 : 1

0.25 : 0.25

HCl : CaCl₂

2 : 1

0.36 : 1/2 × 0.36 = 0.18 mol

The number of moles of CaCl₂ produced by HCl are less it will be limiting reactant.

Mass of CaCl₂ = moles × molar mass

Mass of CaCl₂ =0.18 mol × 110.98 g/mol

Mass of CaCl₂ = 20 g

The calcium carbonate is present in excess.

HCl : CaCO₃

2 : 1

0.36 : 1/2 × 0.36 = 0.18 mol

So, 0.18 moles react with 0.36 moles of HCl.

The moles of CaCO₃ remain unreacted = 0.25 -0.18

The moles of CaCO₃ remain unreacted = 0.07 mol

Mass of of CaCO₃ remain unreacted = Moles × molar mass

Mass of of CaCO₃ remain unreacted = 0.07 mol × 100.1 g/mol

Mass of of CaCO₃ remain unreacted = 7.007 g

7 0

3 years ago

An unknown compound has the following chemical formula:

Softa [21]

Answer:

Formula of the compound = $P_2O_5$

Explanation:

Given,

No. of mole of O = 8.20 mol

No. of mole of P = 3.30 mol

Chemical formula = $P_2O_x$

Ratio of P and O = $\frac{2}{x}$

$\frac{2}{x} =\frac{3.3}{8.20} \\x \times 3.3 = 8.20 \times 2\\x = \frac{8.20 \times 2}{3.3} \\x=4.9969\\ = 5$

formula of the compound = $P_2O_5$

5 0

3 years ago

2NO + 3MnO2 + 4H â 2NO3- + 3Mn2 + 2H2O For the above redox reaction, assign oxidation numbers and use them to identify the eleme

mixer [17]

Answer:

Manganese decreases from 4+ to 2+ (reduced and oxidizing agent) and nitrogen increases from 2+ to 5+ (oxidized and reducing agent).

Explanation:

Hello there!

In this case, according to the given redox reaction, we rewrite it as a convenient first step:

$2NO + 3MnO_2 + 4H^+ \rightarrow 2NO_3^- + 3Mn^{2+} + 2H_2O$

Next, we assign the oxidation numbers as follows:

$2N^{2+}O^{2-} + 3Mn^{4+}O^{-2}_2 + 4H^+ \rightarrow 2(N^{5+}O^{2-}_3)^- + 3Mn^{2+} + 2H^+_2O^{2-}$

Thus, we can see that both manganese and nitrogen undergo a change in their oxidation number, the former decreases from 4+ to 2+ (reduced and oxidizing agent) and the latter increases from 2+ to 5+ (oxidized and reducing agent).

Regards!

4 0

2 years ago

Why is a molecule of CO2 nonpolar even though the bonds between the carbon atom and the oxygen atoms are polar?

schepotkina [342]

The correct answer is option 1. Carbon dioxide is nonpolar because the shape of the molecule is symmetrical. It is a linear molecule where the oxygen atoms are symmetrical on each end. CO2 molecule do not have a region of unequal sharing.

7 0

2 years ago

Describe the differences between polyp and medusa

stealth61 [152]

One difference is that some animals are polyp and some are medusa.

The other difference is that some animals have medusa in their life or polp in their life cycle.

Hope these two differences helps :D

5 0

2 years ago