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3 years ago

4.Identify each substance in the following word equation as a reactant or a product

Chemistry

1 answer:

Anastaziya [24]3 years ago

5 0

Explanation:

4. limestone heat lime + carbon dioxide

The reactants in this expression above is limestone

The products of the reaction is carbon dioxide and lime

Reactant is the species that gives the product and it is usually found on the left hand side of the expression.

The product is the substance on the right hand side of the expression that forms through the experiment.

Heat is used to facilitate the reaction.

5. An exothermic reaction is a reaction in which heat is given off.

An endothermic reaction is a reaction in which heat is absorbed in the process.

An exothermic reaction is always warmer after the reaction whereas an endothermic reaction is colder at the end of the reaction.

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What is the molar mass of a gas which has a density of 0.00249 g/mL at 20.0 degrees celcius and 744.0 mm Hg?

creativ13 [48]

61.24 is the molar mass of a gas which has a density of 0.00249 g/mL at 20.0 degrees celcius and 744.0 mm Hg.

Explanation:

given that:

density = 0.00249 g/ml ( $\frac{mass}{volume}$ ) or 2.49 grams/litre

P = 744 mm Hg OR 0.978 atm

T = 20 Degrees or 293.15 Kelvin

R = 0.08206 Litre atm/mole K

molar mass =?

Formula used/

PV = nRT equation 1

here n is number of moles:

n = $\frac{mass}{atomic mass}$

putting the value of n and value of density in the equation 1:

PV = $\frac{mass}{molar mass}$ x RT

molar mass = $\frac{mass}{volume}$ x $\frac{RT}{P}$

= density x $\frac{RT}{P}$

= $\frac{2.49 x 0.08276 x 293.15}{0.978}$

= 61.24 is the molar mass of the gas.

8 0

2 years ago

NaBr + CaF2 → NaF + CaBr2 What coefficients are needed to balance the chemical equation? A) 1,1,1,1 B) 1,2,1,2 C) 1,2,2,1 D) 2,1

elena-s [515]

D.
2NaBr + CaF2 --> 2NaF + CaBr2 gives you:

2Na 2Na
2Br 2F
1Ca 1Ca
2F 2Br

This is balanced.

7 0

3 years ago

Read 2 more answers

Determine the number of significant figures.

Genrish500 [490]

Answer: A. 4sf B.2sf C.6sf D.1sf E.4sf

Hope this helps! :)

3 0

3 years ago

A mixture of ethyl acetate vapour and air has a relative saturation of 50% at 303 K and a total pressure of 100 kPa. If the vapo

AURORKA [14]

Answer : The correct option is, (b) 0.087

Explanation :

The formula used for relative saturation is:

$\text{Relative saturation}=\frac{P_A}{P_A^o}$

where,

$P_A$ = partial pressure of ethyl acetate

$P_A^o$ = vapor pressure of ethyl acetate

Given:

Relative saturation = 50 % = 0.5

Vapor pressure of ethyl acetate = 16 kPa

Now put all the given values in the above formula, we get:

$0.5=\frac{P_A}{16kPa}$

$P_A=8kPa$

Now we have to calculate the molar saturation.

The formula used for molar saturation is:

$\text{Molar saturation}=\frac{P_{vapor}}{P_{\text{vapor free}}}$

and,

P(vapor free) = Total pressure - Vapor pressure

P(vapor) = $P_A$ = 8 kPa

So,

P(vapor free) = 100 kPa - 8 kPa = 92 kPa

The molar saturation will be:

$\text{Molar saturation}=\frac{P_{vapor}}{P_{\text{vapor free}}}$

$\text{Molar saturation}=\frac{8kPa}{92kPa}=0.087$

Therefore, the molar saturation is 0.087

5 0

3 years ago

The osmotic pressure exerted by a solution is equal to the molarity multiplied by the absolute temperature and the gas constant

zavuch27 [327]

Answer: M = 22/ (i x28.948)

Explanation:

Pi = osmotic pressure = 22atm

T = Temperature = 353K

M = Molarity = ?

R = gas constant = 0.082atm.L/mol/K

i = van’t Hoff factor

Pi = iMRT

M= Pi /(iRT) = 22 / ( i x 0.082 x 353)

M = 22/ (i x28.948)

7 0

3 years ago