Some Basic Concepts of Chemistry Test

Result

Some Basic Concepts of Chemistry Test - 76

Score
-
out of -
Rank
-
out of -

TIME Taken - -

SHARING IS CARING

If our Website helped you a little, then kindly spread our voice using Social Networks. Spread our word to your readers, friends, teachers, students & all those close ones who deserve to know what you know now.

Weekly Quiz Competition

Question 1
1 / -0

What weight of $$NaHSO_3$$ is required to react with $$100mL$$ of solution containing $$0.33g$$ of $$NaIO_3$$ according to the following reaction
$${IO}_{3}^{\Theta}+HS{O}_{3}^{\Theta}\longrightarrow I^{\Theta}+{SO}_{4}^{2-}$$

A
$$0.52g$$

B
$$5.2g$$

C
$$1.04g$$

D
$$10.4g$$

Solution
Question 2
1 / -0

Samples of gases $$O_2, N_2, CO$$ and $$CO_2$$ under the same conditions of temperature and pressure contain the same number of molecules represented by $$X$$. The molecules of oxygen occupy $$V$$ litres and have a mass of $$8\ g$$. Under the same conditions of temperature and pressure, what is the volume occupied by molecules of $$N_2$$?

A
$$2V$$

B
$$4V$$

C
$$\cfrac {V} {2}$$

D
$$V$$
Question 3
1 / -0

$$60$$g of solution containing $$40\%$$ by mass of NaCl are mixed with $$100$$g of a solution containing $$15\%$$ by mass NaCl. Determine the mass percent of sodium chloride in the final solution.

A
$$24.4\%$$

B
$$78\%$$

C
$$48.8\%$$

D
$$19.68\%$$

Solution

Mass of NaCl in 60 g of solution which contains 40% by mass of NaCl = $$ 60 \times \dfrac{40}{100} = 24 g $$
Mass of NaCl in 100 g of solution which contains 15% by mass of NaCl = $$ 100 \times \dfrac{15}{100} = 15 g $$
Total mass of NaCl contained in both solutions = 24 + 15 = 39 g
Total mass of both solutions = 60 + 100 = 160 g
Mass percent of NaCl in the final solution = $$ \dfrac{39}{160} \times 100 $$ = 24.375 % = 24.4 % (approximately)
Question 4
1 / -0

How many grams of concentrated nitric acid solution should be used to prepare $$250\,mL$$ of $$2.0M\,\,\,HN{O_3}$$ ? The concentrated acid is $$70\% \,\,HN{O_3}.$$

A
$$90.0g\,conc.\,\,\,HN{O_3}$$

B
$$70.0g\,conc.\,\,\,HN{O_3}$$

C
$$54.0g\,conc.\,\,\,HN{O_3}$$

D
$$45.0g\,conc.\,\,\,HN{O_3}$$

Solution
Question 5
1 / -0

$$C{O_2}$$ was collected from combustion of lime stone. The mass ratio of carbon and oxygen was found to be $$3:8$$. Find the mass ratio of oxygen and carbon in the $$C{O_2}$$ obtained by burning coke in excess oxygen.

A
$$3:8$$

B
$$8:3$$

C
$$12:32$$

D
none of the above

Solution
Question 6
1 / -0

In the mixture of $$(NaHCO_3 + Na_2CO_3$$) in 1:1 molar ratio, the volume of $$HCl$$ required is $$'x'$$ ml with methyl orange and $$'y'$$ ml with phenolphthalein indicator for 2 different titrations from start for equal volumes of original solution. The relation between $$x$$ and $$y$$ is:

A
$$x = 3y$$

B
$$y = 3x$$

C
$$x =6y$$

D
$$y = 6x$$
Question 7
1 / -0

What changes does not occur in presence of organic solvent when acidified $$K_{2}Cr_{2}O_{7}$$ reacts with $$H_{2}O_{2}$$ solutions?

A
Orange colour of solution turns blue

B
$$O.S$$ of $$Cr$$ atom decreases

C
$$O.S$$ of $$Cr$$ atom remains constant

D
Unpaired electron remain same

Solution
Question 8
1 / -0

100 gm impure $$CaCO_3$$ on heating gives 5.6 lit. $$CO_2$$ gas at NTP. Find the percentage of calcium in $$CaCO_3$$ sample.

A
1

B
40

C
10

D
30

Solution
Question 9
1 / -0

An alloy has $$Fe, Co$$, and $$Mo$$ equal to 71%, 12%, and 12% respectively. How many cobalt atoms are there in a cylinder of radius 2.50 cm and a length of $$10.0\,c{m^2}$$? The density of alloy is $$8.20g/mL$$.

Given:(Atomic weight of $$Co$$ = 58.9u)

A
$$0.198 \times \,\,{10^{23}}$$

B
$$198 \times \,\,{10^{23}}$$

C
$$19.8 \times \,\,{10^{23}}$$

D
$$1.98 \times \,\,{10^{23}}$$
Question 10
1 / -0

A sample of potato starch was ground in a dall mill to give a starch like molecule of lower molecular weight. The product analyzed $$0.086\%$$ phosphorus .If each molecule is assumed to contain one atom of phosphorus. The molecular weight of the material is _______________.

A
$$3.6\times10^{6}$$

B
$$4.9\times10^{4}$$

C
$$7.2\times10^{3}$$

D
$$3.6\times10^{4}$$

Solution