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3 years ago

An element's atomic number (ID number) is equal to the number of ______ that element has.

Chemistry

2 answers:

Veronika [31]3 years ago

5 0

I’m pretty sure it is number of protons

exis [7]3 years ago

3 0

I think the answer should be protons

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c3H8 + 5O2 = 3CO2 + 4H2O When 44.0 grams of propane (C3H8) under goes complete combustion, how many grams of water will be produ

Umnica [9.8K]

<u>Answer:</u> 72 grams of water will be produced.

<u>Explanation:</u>

To calculate the number of moles, we use the formula:

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

Mass of propane = 44 grams

Molar mass of propane = 44 grams

Putting values in above equation, we get:

$\text{moles of propane}=\frac{44g}{44g/mol}=1mole$

For the reaction of combustion reaction of propane, the equation follows:

$C_3H_8+5O_2\rightarrow 3CO_2+4H_2O$

By Stoichiometry of the reaction,

1 mole of propane produces 4 moles of water.

So, 1 mole of propane will produce = $\frac{1}{1}\times 4=4moles$ of water.

Now, to calculate the amount of water, we use equation 1, we get:

Molar mass of water = 18 g/mol

$4mol=\frac{\text{Mass of water}}{18g/mol}$

Mass of water produced = 72 grams

Hence, 72 grams of water will be produced.

6 0

3 years ago

KCI is a molecule. True or False

Monica [59]

Answer: duh

Explanation:

4 0

3 years ago

Read 2 more answers

What are the oxidation numbers for HCL

prisoha [69]

Here's the numbers
H = +1
Cl = -1

5 0

3 years ago

It has been suggested that the surface melting of ice plays a role in enabling speed skaters to achieve peak performance. Carry

Fittoniya [83]

Answer:

a) Pf = 689.4 bar

b) P = 226.6 bar

c) T = 269.99 K

Explanation:

The molar volume of ice is equal to:

Vi = m/p = (18.02x10^-3 kg H2O/1 mol H2O)*(1 m^3/920 kg) = 1.96x10^-5 m^3 mol^-1

The molar volume of liquid water is equal to:

Vl = (18.02x10^-3 kg/1 mol)*(1 m^3/997 kg) = 1.8x10^-5 m^3 mol^-1

The change in volume is equal to:

ΔVchange = Vi-Vl = 1.96x10^-5 - 1.8x10^-5 = 1.5x10^-6 m^3 mol^-1

using the Clapeyron equation:

Pf = Pi + ((ΔHf*ΔT)/(ΔVf*Ti)) = 1.013x10^5 Pa + ((6010 J mol^-1 * 4.7 K)/(1.5x10^-6 * 273.15 K)) = 6.89x10^7 Pa = 689.4 bar

For the pressure we will use the equation:

P = (m*g)/A, where m is the mass, g is the acceleration of gravity and A is the area. Replacing values:

P = (79 kg * 9.81 m s^-2)/(1.9x10^-4 m * 0.18 m) = 2.26x10^7 Pa = 226.6 bar

From Clapeyron´s expression we need to clear ΔT:

ΔT = ((Pf-Pi)*ΔV*Ti)/ΔHf = ((2.26x10^7 - 6.89x10^7)*1.5x10^-6*273.15)/6010 = -3.16 K

you can evaluate the new melting point of ice:

T = Ti + ΔT = 273.15 K - 3.16 K = 269.99 K

4 0

4 years ago

The first known telescopes, used around 1600, consisted of a lens and an eyepiece. Today, telescopes are often computer controll

Veseljchak [2.6K]

Answer:

Explanation:

The telescopes of the 1600s were gradually improved upon over time, resulting in the telescopes that are available today.

4 0

3 years ago