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2 years ago

Name the element which lies in group IA and 3rd period. What is the valency of it and why?

Chemistry

2 answers:

Jlenok [28]2 years ago

4 0

Answer:

Bro I got notification of this question but soory I don't know the answer Hope you understand me

laila [671]2 years ago

3 0

Answer :

Na valency 1

Explanation:

Na -sodium.

This element is in the 1A group, so it has 1 electron on the last (valent) level.

So, only 1 electron can participate in forming chemical bond, and therefore the valency of Na is 1.

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8. How much heat is released when 85.0 g of steam condense to liquid water?

sergeinik [125]

Answer:

199920J

Explanation:

Given parameters:

Mass of steam = 85g

Unknown:

Heat released when the liquid is condensed = ?

Solution:

The heat released by the substance is given as;

H = mL

H is the heat released

m is the mass

L is the latent heat of steam = 2352J/g

Heat released = 85 x 2352 = 199920J

3 0

3 years ago

300 moles of sodium nitrite are needed for a reaction. the solution is 0.450 m. how many ml are needed?

miv72 [106K]

Answer:

$\boxed{\text{667 000 mL}}$

Explanation:

$\text{Molar concentration} = \dfrac{\text{moles}}{\text{litres}}\\\\c = \dfrac{n}{v}$

Data:

c = 0.450 mol·L⁻¹

n = 300 mol

Calculation:

$\begin{array}{rcl}0.450 & = & \dfrac{300}{V}\\\\0.450V& = & 300\\\\V & = & \dfrac{300}{0.450}\\\\V & = & \text{667 L} =\textbf{667 000 mL}\end{array}\\\text{The volume of solution needed is }\boxed{\textbf{667 000 mL}}$

4 0

2 years ago

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 $CaCN_2$

3 0

2 years ago

If the chemical properties of a substance remain unchanged and the appearance or shape of an substance changes it is called a

vladimir1956 [14]

Answer:

Physical change

Explanation:

Physical change -

It is the type of reversible change , where there is change in the state of the matter , is referred to as a physical change .

There is no chemical process involved during state change , i.e. , no new substance is formed .

Hence , from the given statement of the question, the correct term is physical change.

3 0

2 years ago

What are the steps to measure the density of a solid?

JulsSmile [24]

Answer:

Look below

Explanation:

The formula for density is:

$Density=\frac{mass}{volume}$

Therefore in order to find the density of a solid, you must find the mass and the volume first.

To find the mass, you can use a scale.

To find the volume, you can use the water displacement method. For example, if you fill the water of a graduated cylinder to 10 mL, and then you put a rock inside, and it rises to 15 mL, then the volume (of the rock) is 15mL-10mL=5mL.

4 0

2 years ago

Name the element which lies in group IA and 3rd period. What is the valency of it and why?​

Name the element which lies in group IA and 3rd period. What is the valency of it and why?