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3 years ago

A substance that cannot be broken down into other substances by ordinary chemical procedures is an

1 answer:

5 0

An ELEMENT is a substance that cannot be broken down into other substances by ordinary chemical procedures. Some easy examples would be: gold, iron, carbon, hydrogen, oxygen, nitrogen.

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What are parts of the nervous system

Vlad1618 [11]

Answer:

the brain and the spinal cord are the two main parts.

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3 years ago

You have two samples, one is calcite and the other is halite.

beks73 [17]

Answer:

Explanation:

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3 years ago

What happens when an electron moves from a high energy level to a lower one? it absorbs light it emits light it disappears it ge

Marianna [84]

Answer: The correct answer is it emits light.

Explanation:

When an electron is present in ground level that is the lower energy level and moves to the higher energy level, the energy is provided to the electron which means that it absorbs light. This is known as absorption.

When an electron present in the higher energy level comes back to the lower energy level, it emits radiations in the form of light. This is known as emission.

Hence, the correct answer is it emits light.

8 0

3 years ago

A 3.50 g sample of an unknown compound containing only C , H , and O combusts in an oxygen‑rich environment. When the products h

statuscvo [17]

Explanation:

First, calculate the moles of $CO_{2}$ using ideal gas equation as follows.

PV = nRT

or, n = $\frac{PV}{RT}$

= $\frac{1 atm \times 4.41 ml}{0.0821 Latm/mol K \times 293 K}$ (as 1 bar = 1 atm (approx))

= 0.183 mol

As, Density = $\frac{mass}{volume}$

Hence, mass of water will be as follows.

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

0.998 g/ml = $\frac{mass}{3.26 ml}$

mass = 3.25 g

Similarly, calculate the moles of water as follows.

No. of moles = $\frac{mass}{\text{molar mass}}$

= $\frac{3.25 g}{18.02 g/mol}$

= 0.180 mol

Moles of hydrogen = $0.180 \times 2$ = 0.36 mol

Now, mass of carbon will be as follows.

No. of moles = $\frac{mass}{\text{molar mass}}$

0.183 mol = $\frac{mass}{12 g/mol}$

= 2.19 g

Therefore, mass of oxygen will be as follows.

Mass of O = mass of sample - (mass of C + mass of H)

= 3.50 g - (2.19 g + 0.36 g)

= 0.95 g

Therefore, moles of oxygen will be as follows.

No. of moles = $\frac{mass}{\text{molar mass}}$

= $\frac{0.95 g}{16 g/mol}$

= 0.059 mol

Now, diving number of moles of each element of the compound by smallest no. of moles as follows.

C H O

No. of moles: 0.183 0.36 0.059

On dividing: 3.1 6.1 1

Therefore, empirical formula of the given compound is $C_{3}H_{6}O$ .

Thus, we can conclude that empirical formula of the given compound is $C_{3}H_{6}O$ .

6 0

3 years ago

The decomposition of methanol, ch3oh(g), to form ch4(g) and o2(g) absorbs 252.8 kj of heat per mole of oxygen formed. write a ba

Svetllana [295]

The thermochemical equation is the chemical equation including the net change of enthalpy (heat).

The chemical equation for the decomposition of methanol to form methane and oxygen is:

2CH3OH --> 2CH4 + O2

The thermochemical equation is:

2CH3OH ---> 2CH4 + O2 - 252.8 kJ

Note that the heat is placed as negative at the right side because it is absorbed during the decomposition, so the environment will have 252.8 kJ less per each mole of O2 produced.

You can equivalently write:

2CH3OH + 252.8 kJ --> 2CH4 + O2

4 0

4 years ago