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3 years ago

A metal, M, forms an oxide compound with the

Chemistry

1 answer:

lapo4ka [179]3 years ago

5 0

Answer:

Group 1

Explanation: because the compound has a formula of M2O , the number of valence electrons of M should be 1.

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Calculate the enthalpy for this reaction: 2C(s) + H2(g) ---> C2H2(g) ΔH° = ??? kJ Given the following thermochemical equation

nordsb [41]

Answer:

The enthalpy for given reaction is 232 kilo Joules.

Explanation:

$C_2H_2(g) + \frac{5}{2}O_2(g)\rightarrow 2CO_2(g) + H_2O(l), \Delta H^o_{1} = -1,123 kJ$ ...[1]

$C(s) + O_2(g)\rightarrow CO2(g), \Delta H^o_{2} = -340 kJ$ ..[2]

$H_2(g) + \frac{1}{2}O_2(g)\rightarrow H_2O(l) ,\Delta H^o_{3} = -211 kJ$ ..[3]

$2C(s) + H_2(g)\rightarrow C_2H_2(g),\Delta H^o_{4} =?$ ..[4]

2 × [2] + [3] - [1] ( Using Hess's law)

$\Delta H^o_{4}=2\times \Delta H^o_{2}+\Delta H^o_{3} - \Delta H^o_{1}$

$\Delta H^o_{4}=2\times (-340 kJ) + (-211 kJ) - (-1,123 kJ)$

$\Delta H^o_{4}=232 kJ$

The enthalpy for given reaction is 232 kilo Joules.

5 0

2 years ago

When an electron moves from a lower energy level to a higher energy level, the atom:

Ede4ka [16]

Answer:

A. absorbs light

Explanation:

For an electron to move from a lower energy level to a higher energy level, energy needs to be added to the atom.

In most cases this required energy will be light: The electron of the atom will absorb the energy of the light and move to a higher energy level.

When said electron comes back to the lower energy level, the atom will conversely give off light.

5 0

2 years ago

Low concentrations of EDTA near the detection limit gave the following dimensionless instrument readings: 175, 104, 164, 193, 13

Mila [183]

Answer:

Following are the solution to these question:

Explanation:

Calculating the mean:

$\bar{x}=\frac{175+104+164+193+131+189+155+133+151+176}{10}\\\\$

$=\frac{1571}{10}\\\\=157.1$

Calculating the standardn:

$\sigma=\sqrt{\frac{\Sigma(x_i-\bar{x})^2}{n-1}}\\\\$

Please find the correct equation in the attached file.

$=28.195$

For point a:

$=3s+yblank \\\\=3 \times 28.195+50\\\\=84.585+50\\\\=134.585\\$

For point b:

$=3 \ \frac{s}{m}\\\\ = \frac{(3 \times 28.195)}{1.75 \times 10^9 \ M^{-1}}\\\\= 4.833 \times 10^{-8} \ M$

For point c:

$= 10 \frac{s}{m} \\\\= \frac{(10 \times 28.195)}{1.75 x 10^9 \ M^{-1}}\\\\ = 1.611 \times 10^{-7}\ M$

It is calculated by using the slope value that is $1.75 \times 10^9 M^{-1}$ . The slope value $1.75 \times 10^9 M^{-1}$ is ambiguous.

7 0

2 years ago

(2-2) Looking at the chemical formula CaF2 (calcium fluoride), what do you think this substance is made of? (Choose ALL that app

mixer [17]

Answer:

Metal

Non-metal

Explanation:

CaF2 is an ionic compound. Ionic compounds are mostly composed of a metal and a non metal. Metals donate electrons to non-metals to form ionic compounds.

Calcium is a divalent ion of group two in the periodic table while F is a univalent nonmetal of group 17 in the periodic table. Hence the compound CaF2 is composed of a metal and a nonmetal.

7 0

2 years ago

Several billion years ago, which gas was the least prevalent in the atmosphere?

Amiraneli [1.4K]

The least prevalent gas in the atmosphere was oxygen several billion years ago. This is because it was only around 2.4-3 billion years ago when the first photosynthetic bacteria evolved, meaning they produce food from inorganic compounds such as carbon dioxide and water to produce glucose and oxygen. Oxygen is then released in the atmosphere and this is called <em>The Great Oxygenation Event</em>.

7 0

2 years ago