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2 years ago

A student creates a mixture of water and washing soda weighing 10 g and a mixture of

Chemistry

1 answer:

Anni [7]2 years ago

8 0

Answer: The weight of the products should be the same after he mixes them.

Explanation: The law of the conservation of mass states that the mass of the products in a chemical reaction must equal the mass of the reactants. Even if the products are changed or rearranged, the products and reactants will still have the same mass

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A student dissolved 4.00 g of Co(NO3)2 in enough water to make 100. mL of stock solution. He took 4.00 mL of the stock solution

mihalych1998 [28]

Answer:

0.08097 grams of nitrate ions are there in the final solution.

Explanation:

Moles of cobalt(II) nitrate ,n= $\frac{4.00 g}{245 g/mol}=0.01633 mol$

Volume of the cobalt(II) nitrate solution, V = 100.0 mL = 0.1 L

$Molarity=\frac{n}{V(L)}$

Let the molarity of the solution be $M_1$

$M_1=\frac{0.01633 mol}{0.1 L}=0.1633 M$

A students then takes 4 .00 mL of $M_1$ solution and dilute it to 275 ml.

$M_1=0.1633 M$

$V_1=4.00 mL$

$M_2=?$ (molarity after dilution)

$V_2=275 mL$ (after dilution)

$M_1V1=M-2V_2$

$M_2=\frac{M_1V_1}{V_2}=\frac{0.1633 M\times 4.00 mL}{275 mL}=0.002375 M$

Molarity of the of solution after dilution is 0.002375 M.

$Co(NO_3)_2(aq)\rightarrow Co^{2+}(aq)+2NO_3^{-}(aq)$

1 mol of cobalt(II) nitrate gives 2 moles of nitrate ions. Then 0.002375 M solution of cobalt (II) nitrate will give:

$[NO_3^{-}]=\frac{2}{1}\times 0.002375 M=0.004750 M$

Moles of nitrate ions = n

Volume of the solution = 275 mL = 0.275 L

Molarity of the nitrate ions = $[NO_3^{-}]=0.004750 M$

$[NO_3^{-}]=\frac{n}{0.275 L}$

n = 0.001306 mol

Mass of 0.001306 moles of nitrate ions:

0.001306 mol × 62 g/mol= 0.08097 g

0.08097 grams of nitrate ions are there in the final solution.

4 0

2 years ago

An atom of beryllium (m = 8.00 u) splits into two atoms of helium (m = 4.00 u) with the release of 92.2 kev of energy. if the or

galben [10]

The kinetic energy of the products is equal to the energy liberated which is 92.2 keV. But let's convert the unit keV to Joules. keV is kiloelectro volt. The conversion that we need is: 1.602×10⁻¹⁹ <span>joule = 1 eV

Kinetic energy = 92.2 keV*(1,000 eV/1 keV)*(</span>1.602×10⁻¹⁹ joule/1 eV) = 5.76×10²³ Joules

From kinetic energy, we can calculate the velocity of each He atom:
KE = 1/2*mv²
5.76×10²³ Joules = 1/2*(4)(v²)
v = 5.367×10¹¹ m/s

4 0

2 years ago

Read 2 more answers

How does the arrangement of atoms in a mineral relate to its properties?

MakcuM [25]

The arrangement of atoms in a mineral can change its physical and chemical properties.
Diamonds and coal are both made of carbon, however, their chemical and physical properties are very different.

6 0

2 years ago

Read 2 more answers

What is the sequence of energy transformations that occur in a nuclear reactor? nuclear energy Right arrow. Mechanical energy Ri

Mademuasel [1]

Answer:

NUCLEAR ENERGY -----> MECHANICAL ENERGY -------> THERMAL ENERGY --------> ELECTRICAL ENERGY

Explanation:

In nuclear reactor, various energy transformations occur in order to generate electricity. Nuclear reactor converts the energy released from nuclear fission and the heat generated is removed from the reactor by a cooling system where steam is generated. The steam then drives a turbine which powers a generator to produce electricity.

A nuclear reactor is hence an equipment where nuclear chain reactions occur and control can be obtained. The nuclear reactor uses mostly uranium-235 and Plutonium-239. When these radioactive substances absorbs neutrons, they undergo nuclear fission causing the nucleus to split into two or more smaller compounds with the release of kinetic energy a form of mechanical energy, gamma radiations and others.The kinetic energy is then harnessed in the equipment as heat (thermal energy) which is received by a cooling system and steam is generated. The steam can then power the generator from which electricity is obtained (electrical energy).

So therefore, in a nuclear reactor, the nuclear energy is transformed to mechanical energy and then thermal energy which powers the generation of the electrical energy.

6 0

2 years ago

If 6 g of element k combine with 17 g of element l, how many grams of element k combine with 85 g of element l?

Ede4ka [16]

Hope this helps you.

5 0

2 years ago