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3 years ago

PLEASE HELP!!!!LIKE NOW!!!

Chemistry

1 answer:

dsp733 years ago

6 0

I'm not completely sure on this and I apologize if it's wrong, but I believe it's B) Newton's Law.

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1. write the complete chemical symbol for the ion with 14 protons 15 neutrons and 18 electrons

motikmotik

Answer:

1. $Si^{-4}$

2. $Co^{+2}$

Explanation:

An ion is formed when an atom that is said to be neutral gains or losses electrons.

It is thought that a negative ion (anion) is produced as it gains electrons and a positive ion (cation) is formed when it loses an electron.

Atomic number is the total number of protons and electrons in a neutral atom.

From the information

Protons = 14

electron = 18

Net Charge = no of proton - no of electron

= 14 - 18 = -4

Mass number = 14 + 15 = 29

Thus, the chemical symbol = $Si^{-4}$

For ion with 27 proton, 32 neutrons and 25 electrons

Net charge = 27 - 25 = +2

Mass number = 27 + 32 = 59

Thus, the chemical symbol = $Co^{+2}$

6 0

3 years ago

Liquid hexane

maks197457 [2]

Answer: The mass of $H_2O$ produced is 2.52 g

Explanation:

The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ ......(1)

For hexane:

Given mass of hexane = 1.72 g

Molar mass of hexane = 86.18 g/mol

Putting values in equation 1, we get:

$\text{Moles of hexane}=\frac{1.72g}{86.18g/mol}=0.020mol$

For oxygen gas:

Given mass of oxygen gas = 8.0 g

Molar mass of oxygen gas= 32 g/mol

Putting values in equation 1, we get:

$\text{Moles of water}=\frac{8.0g}{32g/mol}=0.25mol$

The chemical equation for the combustion of hexane follows:

$2C_6H_{14}+19O_2\rightarrow 12CO_2+14H_2O$

By stoichiometry of the reaction:

If 2 moles of hexane reacts with 19 moles of oxygen gas

So, 0.020 moles of hexane will react with = $\frac{19}{2}\times 0.020=0.19mol$ of oxygen gas

As the given amount of oxygen gas is more than the required amount. Thus, it is present in excess and is considered as an excess reagent.

Thus, hexane is considered a limiting reagent because it limits the formation of the product.

By the stoichiometry of the reaction:

If 2 moles of hexane produces 14 moles of $H_2O$

So, 0.020 moles of hexane will produce = $\frac{14}{2}\times 0.020=0.14mol$ of $H_2O$

We know, molar mass of $H_2O$ = 18 g/mol

Putting values in above equation, we get:

$\text{Mass of }H_2O=(0.14mol\times 18g/mol)=2.52g$

Hence, the mass of $H_2O$ produced is 2.52 g

4 0

3 years ago

How many kilometers are in a 7.21. mm

Readme [11.4K]

Answer:

0.00000721 Kilometer

6 0

3 years ago

Which best describes the particles in a gas when the temperature rises from 23 °C to 46 °C?

mariarad [96]

I think the correct answer is b. Temperature is proportional to the average kinetic energy so when temperarure rises so will the average kinetic energy. I hope this helps. Let me know if anything is unclear.

5 0

3 years ago

A wave with low energy will also have high frequencies and long wavelength. short wavelengths and high frequencies. low frequenc

ch4aika [34]

A wave with low energy will also have long wavelengths and low frequencies.

The given in a single photon of a wave is given by Planck's equation:
E = hc/λ
and
E = hf

Where λ is the wavelength and f is the frequency of the photon. This means that energy is directly proportional to the frequency and inversely proportional to the wavelength. Thus, it is visible that photons with a lower frequency and a longer wavelength will have a lower energy.

8 0

3 years ago

Read 2 more answers