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2 years ago

4. The elements calcium and strontium have similar chemical properties because they both have the same

Chemistry

2 answers:

Zarrin [17]2 years ago

6 0

Answer:

Answer c

Explanation:

The similar properties between calcium, strontium and potassium are : All of them have two electrons in the outermost shell. All are metals. Their oxides are alkaline.

mestny [16]2 years ago

4 0

The answer is C Becuase all of them have have two electrons in the outermost shells which is metal .

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Burning a compound of calcium, carbon, and nitrogen in oxygen in a combustion train generates calcium oxide , carbon dioxide , n

mylen [45]

The question is incomplete, here is the complete question:

Burning a compound of calcium, carbon, and nitrogen in oxygen in a combustion train generates calcium oxide (CaO), carbon dioxide $(CO_2)$ , nitrogen dioxide $(NO_2)$ , and no other substances. A small sample gives 2.389 g CaO, 1.876 g $CO_2$ , and 3.921 g $NO_2$ Determine the empirical formula of the compound.

Answer: The empirical formula for the given compound is $CaCN_2$

Explanation:

The chemical equation for the combustion of compound having calcium, carbon and nitrogen follows:

$Ca_xC_yN_z+O_2\rightarrow CaO+CO_2+NO_2$

where, 'x', 'y' and 'z' are the subscripts of calcium, carbon and nitrogen respectively.

We are given:

Mass of CaO = 2.389 g

Mass of $CO_2=1.876g$

Mass of $NO_2=3.921g$

We know that:

Molar mass of calcium oxide = 56 g/mol

Molar mass of carbon dioxide = 44 g/mol

Molar mass of nitrogen dioxide = 46 g/mol

For calculating the mass of carbon:

In 44g of carbon dioxide, 12 g of carbon is contained.

So, in 1.876 g of carbon dioxide, $\frac{12}{44}\times 1.876=0.5116g$ of carbon will be contained.

For calculating the mass of nitrogen:

In 46 g of nitrogen dioxide, 14 g of nitrogen is contained.

So, in 3.921 g of nitrogen dioxide, $\frac{14}{46}\times 3.921=1.193g$ of nitrogen will be contained.

For calculating the mass of calcium:

In 56 g of calcium oxide, 40 g of calcium is contained.

So, in 2.389 g of calcium oxide, $\frac{40}{56}\times 2.389=1.706g$ of calcium will be contained.

To formulate the empirical formula, we need to follow some steps:

Step 1: Converting the given masses into moles.

Moles of Calcium = $\frac{\text{Given mass of Calcium}}{\text{Molar mass of Calcium}}=\frac{1.706g}{40g/mole}=0.0426moles$

Moles of Carbon = $\frac{\text{Given mass of Carbon}}{\text{Molar mass of Carbon}}=\frac{0.5116g}{12g/mole}=0.0426moles$

Moles of Nitrogen = $\frac{\text{Given mass of Nitrogen}}{\text{Molar mass of Nitrogen}}=\frac{1.193g}{14g/mole}=0.0852moles$

Step 2: Calculating the mole ratio of the given elements.

For the mole ratio, we divide each value of the moles by the smallest number of moles calculated which is 0.0426 moles.

For Calcium = $\frac{0.0426}{0.0426}=1$

For Carbon = $\frac{0.0426}{0.0426}=1$

For Nitrogen = $\frac{0.0852}{0.0426}=2$

Step 3: Taking the mole ratio as their subscripts.

The ratio of Ca : C : N = 1 : 1 : 2

Hence, the empirical formula for the given compound is $CaCN_2$

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2 years ago

If Steve self-pollinates, what is the likelihood that his offspring will be green?

Pani-rosa [81]

Answer:

100%

Explanation:

My teacher just asked this question.

6 0

3 years ago

Science does not include beliefs or opinions theories laws conclusions

denpristay [2]

Beliefs or opinions

8 0

3 years ago

Cho recorded the weather in her town for a week. She wrote down her observations in the table below. Mon Tue Wed Thu Fri Sat Sun

SIZIF [17.4K]

Answer:

If this trend continues, the following week will be cooler, and a large amount of rain will fall.

Explanation:

Patterns and trends can often be found in data sets. During the week that Cho recorded the weather, the temperatures consistently dropped by one to four degrees each day. At the end of the week, the amount of precipitation increased daily.

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3 years ago

In which model are atoms are imagined as tiny balls?

kobusy [5.1K]

Dalton's Billiard Ball Model

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3 years ago