Recent questions tagged unit1

In nature,abundance of $^1H_1$ and $^2H_1$ are 99.985 and 0.015 percent respectively and water obtained from it contains $H_2O$ and $D_2O$.The number of $D_2O$ molecules in 400mL water (if density is assumed to be 1.0g/mL) will be :

asked Oct 25, 2013 by sreemathi.v

1 answer

Haemoglobin $(C_{2952}H_{9664}N_{812}O_{832}S_8Fe_4)$ is oxygen carrier. If a person has $5L$ blood and each mL of blood has $5\times 10^9$ R.B.C and each R.B.C has $2.8\times 10^8$ haemoglobin molecules, then how many grams of haemoglobin is present in the body of that person?

asked Oct 25, 2013 by sreemathi.v

1 answer

A silicon (atomic weight=28) chip used in an integrated circuit of a microcomputer has a mass of 5.68 mg. How many silicon (Si) atoms are present in this chip.

asked Oct 25, 2013 by sreemathi.v

1 answer

In the first world war ,$1.1\times 10^8$kg of position gas were fired on the allied forces.If the gas is assumed to be phosgene,how many molecules of the gas correspond to the amount fired on allied forces.

asked Oct 25, 2013 by sreemathi.v

1 answer

$\large\frac{2}{3}$ of the atoms in water molecule are hydrogen .What % weight of a water molecule is the weight of 2 hydrogen atoms:

asked Oct 25, 2013 by sreemathi.v

1 answer

16g $SO_x$ occupies 5.6 litres at STP. Assuming the nature of the gas to be ideal, the value of $x$ is

asked Oct 25, 2013 by sreemathi.v

1 answer

Chlorophyll,a green coloring matter contains 2.68% mg.The number of atoms of mg present 1g chlorophyll are

asked Oct 24, 2013 by sreemathi.v

1 answer

4.4g of $CO_2$ and $2.24$ litre of $H_2$ at STP are mixed in a container.The total number of molecules present in the container will be

asked Oct 24, 2013 by sreemathi.v

1 answer

224 ml of triatomic gas weights 1g at 173k and 1atm .The mass of one atom of this gas is

asked Oct 24, 2013 by sreemathi.v

1 answer

Weight of oxygen in $Fe_2O_3$ and FeO in the simple ratio for the same amount of Fe is

asked Oct 24, 2013 by sreemathi.v

1 answer

Two elements $X$ and $Y$ have atomic mass 75 and 16 respectively.They combine to give a compound having 75.8%X.The formula is

asked Oct 24, 2013 by sreemathi.v

1 answer

Two oxides of a metal contain 50% and 40% of metal M respectively.If the formula of first oxide is MO,+ve formula of $2^{nd}$ oxide will be

asked Oct 24, 2013 by sreemathi.v

1 answer

An organic compound containing C and it has 92.3% carbon .Its empirical formula is :

asked Oct 24, 2013 by sreemathi.v

2 answers

A compound has an empirical formula $C_2H_4O$.An independent analysis gave a value of 132.16 for its molecular mass.What is the correct molecular formula ?

asked Oct 24, 2013 by sreemathi.v

1 answer

An organic compound contains 49.30% carbon,6.84% hydrogen and its vapour density is 73.Molecular formula of compound is

asked Oct 24, 2013 by sreemathi.v

1 answer

A compound on analysis,was found to have the following composition :(i) Na=14.31% (ii) S=9.97% (iii) O=69.50% (iv) H=6.22%.Calculate the molecular formula of the compound assuming that whole of hydrogen in the compound is present as water of crystallization .Molecular mass of the compound is 322.

asked Oct 24, 2013 by sreemathi.v

1 answer

A carbon compound containing only carbon and oxygen has an approximate molecular mass of 290.On analysis,it is found to contain 50% by mass of each element .What is the molecular formula of the compound?

asked Oct 24, 2013 by sreemathi.v

1 answer

A compound of carbon ,hydrogen and nitrogen contains these elements in the ratio 9 : 1 : 3.5.Calculate the empirical formula.If its molecular mass is 108,what is the molecular formula ?

asked Oct 24, 2013 by sreemathi.v

1 answer

A compound contains 34.8% Oxygen,52.2% Carbon and 13.0% hydrogen .What is the empirical formula mass of the compound ?

asked Oct 24, 2013 by sreemathi.v

1 answer