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4 years ago

The number of protons in an atom is called?

Chemistry

2 answers:

xz_007 [3.2K]4 years ago

8 0

The number of protons in an atom is called the proton number or the atomic number. Hope this helps! :)

<h2>-CloutAnswers</h2>

Serhud [2]4 years ago

3 0

The thing that it is called is it is called the atomic number of the thing

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What size container should you use when mixing chemicals

NNADVOKAT [17]

My professor told me to use a 500ml beaker depending on what your mixing.

5 0

3 years ago

To what temperature should 2.3L of a gas at 25degree Celsius be heated in order to expand its volume to 4 L under constant press

lakkis [162]

Answer:

518.52K

Explanation:

Charles law, which describes the direct relationship between the volume and the temperature of a gas when the pressure is constant, will be used for this question. The Charles law equation is:

V1/T1 = V2/T2

Where; V1 is the volume of the gas at an initial state (Litres)

T1 is the absolute temperature of the gas at an initial state (Kelvin)

V2 is the volume of the gas at a final state (Litres)

T2 is the absolute temperature of the gas at a final state (Kelvin)

According to the question, V1 = 2.3L, T1 = 25°C, V2 = 4L, T2 = ?

We need to convert the temperature to the absolute temperature unit in Kelvin (K) i.e.

T(K) = T(°C) + 273.15

T(K) = 25°C + 273.15

T1 (K) = 298.15K

To find for T2 in the equation, we make T2 the subject of the formula:

T2 = V2 × T1 / V1

T2 = 4 × 298.15 / 2.3

T2 = 1192.6/2.3

T2 = 518.52

Thus, the temperature must be heated to 518.52K in order to expand to a volume of 4L. This answer is in accordance to Charles law that the volume increases with increase in temperature and vice versa.

5 0

3 years ago

When hydrochloric acid is poured over potassium sulfide, 42.5 mL of hydrogen sulfide gas is produced at a pressure of 756 torr a

EastWind [94]

<h2>Answer:</h2> $0.1899grams$

<h2>Explanations:</h2>

The balanced chemical reaction between hydrochloric acid and potassium sulfide is as shown:

$K_2S+2HCl\to H_2S+2KCl$

Based on stoichiometry, we can see that 1 mole of potassium sulfide reacted to form 1 mole of hydrogen sulfide.

Get the mole of hydrogen sulfide gas (H2S) using the ideal gas equation expressed as:

$\begin{gathered} PV=\text{nRT} \\ n=\frac{PV}{RT} \end{gathered}$

P is the pressure of the gas (in atm) = 0.994737atm (756torr)

V is the volume of the gas = 42.5mL = 0.0425L

T is the temperature (in Kelvin) = 26 + 273 = 299K

R is the gas constant = 0.0821 L*atm/mole * K

Substitute these values into the formula as shown:

$\begin{gathered} n=\frac{0.994737\cancel{\text{atm}}\times0.0425\cancel{L}}{0.0821\frac{\cancel{L}\cdot\cancel{\text{atm}}}{\text{mole}\cdot\cancel{K}}\times299\cancel{K}} \\ n=\frac{0.994737\times0.0425}{0.0821\times299} \\ n=\frac{0.0422763225}{24.5479} \\ n=0.00172\text{moles} \end{gathered}$

Since the number of moles of hydrogen sulfide is 0.00172moles, the number of moles of potassium sulfide will also be 0.00172 moles (based on stoichiometry)

Get the mass of potassium sulfide that reacted using the formula:

$\text{Mass}=number\text{ of moles}\times molar\text{ mass}$

Number of moles of K2S = 0.00172 moles

Molar mass of K2S = 110.262 g/mol

Substitute into the formula for calculating the mass;

$\begin{gathered} \text{Mass}=0.00172\cancel{\text{moles}}\times\frac{110.262g}{\cancel{\text{mole}}} \\ \text{Mass}=0.1899\text{grams} \end{gathered}$

Therefore the mass of potassium sulfide that reacted (in grams) is approximately 0.1899grams

3 0

1 year ago

A sample of pure copper has a mass of 5 grams calculate its volume

kolbaska11 [484]

Moles of cu = mass/Ar
= 5/Ar
=ans

1 mole = 24dm3

Vol of cu = ans/1 × 24dm3
=ans

sorry i have no calculator with me now

4 0

3 years ago

Heat in the amount of 100 kJ is transferred directly from a hot reservoir at 1400 K (TH) to a cold reservoir at 600 K. Calculate

klasskru [66]

Answer:

ΔS = - 0.125 Kj/K decreased entropy

Explanation:

From ΔH = TΔS => ΔS = ΔH/T

= 100Kj/(600K - 1400K) = - 188Kj/800K = - 0.125 Kj/K

Entropy in the cooler flask would have 'decreased' (i.e.; more ordered state) at 600K.

6 0

3 years ago