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2 years ago

Marie mixed 5g of carbon with 5g of lead oxide. she heated the mixture strongly for 15 minutes in a fume cupboard.

Chemistry

1 answer:

olga2289 [7]2 years ago

7 0

The problem talks about two questions and these are:

1. Metals are very good conductors of electricity and heat. Directing heat is easier. So let Marie heat the beads and also have heat another substance, for instance, water. If the beads heat quicker, then they are metals. Another test to conduct is called flame test. This test should give you a colored flame (blue/white for lead) the metal is lead if the reaction is: 2PbO+C ==> 2Pb +CO2

2. The beads are possibly to be lead since Ferrous(lead) oxide + carbon = carbon dioxide + lead

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Which mass of gas would occupy a volume of 3dm3 at 25°C and 1 atmosphere pressure?

balu736 [363]

Answer:

C 8.09 SO2 gas

Explanation:

As we have the volume (3dm³ = 3L), temperature (25°C + 273 = 298K), and pressure (1atm), we can solve to moles of gas using:

PV = nRT

PV / RT = n

1atm*3L / 0.082atmL/molK*298K =¨

0.123 moles of gas you have.

Now, to convert these moles to mass we use molar mass (32g/mol for O2, 28g/mol for N2, 64g/mol for SO2, and 44g/mol for CO2).

Mass of 0.123 moles of these gases is:

O2 = 0.123 moles * 32g/mol = 3.94g of O2. A is wrong

N2 = 0.123 moles * 28g/mol = 3.4g of N2. B is wrong

SO2 = 0.123 moles * 64.1g/mol = 7.9g of SO2≈ 8.09g of SO2, C is possible

CO2 = 0.123 moles * 44g/mol = 5.4g of CO2. D is wrong

Right answer is:

8 0

2 years ago

If the speed of a vehicle increases by 22%, by what factor does its kinetic energy increase?

Mila [183]

Answer:

The kinetic increases by 48.84 %

Explanation:

The expression for the kinetic energy is:-

$K.E.=\frac{1}{2}\times mv^2$

Where, m is the mass of the object

v is the velocity of the object

Let the new velocity is:- v'

v is increased by 22 %. Thus, v' = 1.22 v

So, the new kinetic energy is:-

$K.E.'=\frac{1}{2}\times mv'^2=\frac{1}{2}\times m{1.22}^2=\frac{1}{2}\times mv^21.4884=1.4884K.E.$

<u>Thus, the kinetic increases by 48.84 %</u>

7 0

2 years ago

Read 2 more answers

Be sure to answer all parts. Consider the following balanced redox reaction (do not include state of matter in your answers): 2C

timurjin [86]

Answer:

The specie which is oxidized is:- $CrO_2^-$

The specie which is reduced is:- $ClO^-$

Explanation:

Oxidation reaction is defined as the chemical reaction in which an atom looses its electrons. The oxidation number of the atom gets increased during this reaction.

$X\rightarrow X^{n+}+ne^-$

Reduction reaction is defined as the chemical reaction in which an atom gains electrons. The oxidation number of the atom gets reduced during this reaction.

$X^{n+}+ne^-\rightarrow X$