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3 years ago

8

How do we find mass number of elements in chemistry ?

1 answer:

sukhopar [10]3 years ago

5 0

Answer: Atomic number, atomic mass, and relative atomic mass

Explanation:

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_Cuo +H, → _Cu + _H,0

Elena-2011 [213]

<h3>Answer:</h3>

CuO(s) + H₂(g) → Cu(s) + H₂O(l)

<h3>Explanation:</h3>

Assuming the reaction is the reduction of CuO by H₂
Then the balanced equation for the reaction is;

CuO(s) + H₂(g) → Cu(s) + H₂O(l)

The equation shows the reducing property of hydrogen gas, such that hydrogen reduces metal oxides such as copper(ii)oxide to the respective metals.
The law of conservation requires chemical equations to be balanced so as the mass of reactants will be equal to that of products.

In this case; there is 1 copper atom, 1 oxygen atom and 2 hydrogen atoms on both side of the equation and thus the equation is balanced.

3 0

2 years ago

Measurements show that the energy of a mixture of gaseous reactants increases by during a certain chemical reaction, which is ca

TEA [102]

<h2>Endothermic and Exothermic</h2>

Explanation:

An exothermic response discharges heat and endothermic absorbs to heat
The whole of the enthalpies of the reactants is more prominent than the product, the response will be exothermic
In the product that the items side has a bigger enthalpy, the reaction is endothermic
An exothermic method is one that emits heat. This heat is transferred to the environment
An endothermic reactions is one in which heat must be provided to the system from the environment

8 0

3 years ago

write the chemical formula of the following compounds sodium sulfate magnesium chloride aluminum nitrate ammonium sulfate

tekilochka [14]

Explanation:

Magnesium chloride = MgCl₂

aluminum nitrate= Al(NO₃)₃

ammonium sulfate=( NH₄)₂SO₄

3 0

2 years ago

A chemist prepares a sample of helium gas at a certain pressure, temperature and volume and then removes all but a fourth of the

cupoosta [38]

Answer:

The temperature must be changed to 4 times of the initial temperature so as to keep the pressure and the volume the same.

Explanation:

Pressure in the container is P and volume is V.

Temperature of the helium gas molecules = $T_1$

Molecules helium gas = x

Moles of helium has = $n_1= \frac{x}{N_A}$

PV = nRT (Ideal gas equation)

$PV=n_1RT_1$ ...[1]

After removal of helium gas only a fourth of the gas molecules remains and pressure in the container and volume should remain same.

Molecules of helium left after removal = $\frac{x}{4}$

Moles of helium has left after removal = $n_2= \frac{x}{4\times N_A}$

$PV=n_2RT_2$ ...[2]

$n_1RT_1=n_2RT_2$

$\frac{x}{N_A}\times T_1=\frac{x}{4\times N_A}\times T_2$

$T_1=\frac{T_2}{4}$

$T_2=4T_1$

The temperature must be changed to 4 times of the initial temperature so as to keep the pressure and the volume the same.

6 0

3 years ago

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AnnZ [28]

Answer:

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6 0

3 years ago