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3 years ago

What are compounds????????????????

Chemistry

2 answers:

sweet [91]3 years ago

8 0

Answer:

Compounds are pure substance consisting of two or more different atoms

Debora [2.8K]3 years ago

8 0

Answer:

I hope this help

Explanation:

pls brainliest

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night vision glasses detect energy

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3 years ago

The element in Group 14 Period 4 has how many neutrons and is it a metal, nonmetal, metalloid or noble gas.

monitta

Number of neutrons=41, and it is metalloid

<h3>Further explanation</h3>

Group 14⇒valence electron = 4(ns²np²)

Period 4⇒n=4

So electron configuration of the element :

1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4p² = 32 electron=atomic number

The element with atomic number 32, which is in period 4 and group 14 is Ge-Germanium

There are seven elements that can be classified as metalloids, namely boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te), and polonium (Po).

While the mass number: 73

So the number of neutrons = mass number-atomic number

$\tt 73-32=41$

8 0

3 years ago

Calculate the standard reaction enthalpy for the reaction NO2(g) → NO(g) + O(g) given +142.7 kJ/mol for the standard enthalpy of

bulgar [2K]

Answer:

The standard reaction enthalpy for the given reaction is 235.15 kJ/mol.

Explanation:

$O_2(g) \rightarrow \frac{2}{3}O_3(g),\Delta H^o_{1}=142.7 kJ/mol$ ..[1]

$O_2(g) \rightarrow 2 O(g),\Delta H^o_{2}=498.4 kJ/mol$ ..[2]

$NO(g) + O_3(g)\rightarrow NO_2(g) + O_2(g) ,\Delta H^o_{3} = -200 kJ/mol$ ..[3]

$NO_2(g)\rightarrow NO(g) + O(g),\Delta H^o_{4}=?$ ..[4]

Using Hess's law:

Hess’s law of constant heat summation states that the amount of heat absorbed or evolved in a given chemical equation remains the same whether the process occurs in one step or several steps.

2 × [4] = [2]- (3 ) × [1] - (2) × [3]

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

$2\times \Delta H^o_{4}=498.4 kJ/mol-3\times 142.7 kJ/mol-2\times -200 kJ/mol$

$2\times \Delta H^o_{4}=470.3 kJ/mol$

$\Delta H^o_{4}=\frac{470.3 kJ/mol}{2}=235.15 kJ/mol$

The standard reaction enthalpy for the given reaction is 235.15 kJ/mol.

7 0

3 years ago

Which of the following measurements is equal to 150 dL?

MrRissso [65]

This is a case of metric system of measurements. The scale of the metric system only differs by a factor of 10. The scale (from greatest to least) is kiloliter, hectoliter, dekaliter, liter, deciliter, centiliter and milliliter. If the unit is 150 dL, and you want to find the equivalent dkL measurement, just move the decimal point 2 decimals places to the left (just follow the scale). The same procedure is done for the other metric units.

150 dL = 1.5 dkL
150 dL = 15 L
150 dL = 1,500 cL
150 dL = 15,000 mL

From the choices, the answer is letter C.

6 0

3 years ago

A block has a mass of 25 grams and a volume of 24.5 cm3 what is the<br> density of the block?

schepotkina [342]

Answer:

<h3>The answer is 1.02 g/cm³</h3>

Explanation:

The density of a substance can be found by using the formula

$density = \frac{mass}{volume} \\$

From the question

mass of block = 25 g

volume = 24.5 cm³

The density of the block is

$density = \frac{25}{24.5} \\ = 1.020408163...$

We have the final answer as

Hope this helps you

7 0

3 years ago