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dedylja [7]
3 years ago
9

If an element has 12 protons, 13 neutrons, and 15 electrons, what is its mass?

Chemistry
1 answer:
-BARSIC- [3]3 years ago
7 0

Answer:

25

Explanation:

mass number = protons + neutrons

= 13 + 12 = 25

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A gas evolved during the fermentation of alcohol had a volume of 19.4 L at 17 °C and 746 mmHg. How many moles of gas were collec
AlexFokin [52]

Answer:- 0.800 moles of the gas were collected.

Solution:- Volume, temperature and pressure is given for the gas and asks to calculate the moles of the gas.

It is an ideal gas law based problem. Ideal gas law equation is used to solve this. The equation is:

PV=nRT

Since it asks to calculate the moles that is n, so let's rearrange this for n:

n=\frac{PV}{RT}

V = 19.4 L

T = 17 + 273 = 290 K

P = 746 mmHg

we need to convert the pressure from mmHg to atm and for this we divide by 760 since, 1 atm = 760 mmHg

P=746mmHg(\frac{1atm}{760mmHg})

P = 0.982 atm

R = 0.0821\frac{atm.L}{mol.K}

Let's plug in the values in the equation to get the moles.

n=\frac{0.982atm*19.4L}{0.0821\frac{atm.L}{mol.K}*290K}

n = 0.800 moles

So, 0.800 moles of the gas were collected.

4 0
4 years ago
A calorimeter contains 100 g of water at 39.8 ºC. A 8.23 g object at 50 ºC is placed inside the calorimeter. When equilibrium ha
Tju [1.3M]
When equilibrium has been reached so, according to this formula we can get the specific heat of the unknown metal and from it, we can define the metal as each metal has its specific heat:

Mw*Cw*ΔTw = Mm*Cm*ΔTm

when 
Mw → mass of water
Cw → specific heat of water
ΔTw → difference in temperature for water 

Mm→ mass of metal
Cw→ specific heat of the metal
ΔTm → difference in temperature for metal

by substitution:

100g * 4.18 * (40-39.8) = 8.23 g * Cm * (50-40)

∴ Cm = 83.6 / 82.3 = 1.02 J/g.°C

when the Cm of the Magnesium ∴ the unknown metal is Mg
6 0
3 years ago
What are slime Molds?
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Answer:

Slime mold or slime mould is an informal name given to several kinds of unrelated eukaryotic organisms that can live freely as single cells, but can aggregate together to form multicellular reproductive structures. Slime molds were formerly classified as fungi but are no longer considered part of that kingdom.

5 0
3 years ago
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What are three ways heat is transfered
Gre4nikov [31]

Answer:

Conduction, Convection and Radiation

Explanation:

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3 years ago
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What is the difference between a molecular formula and a molecular model?
snow_tiger [21]
 <span>Molecular compounds, which are represented by molecules, are usually made of non-metals only (or of metalloids and non-metals). Ionic compounds, which are represented by formula units, are made of metals and non-metals. 

More detail if you're interested: Molecules and formula units are the representative particles for molecular and ionic compounds, respectively. By that I mean, one unit of a molecular compound is a molecule...a bundle of atoms covalently bonded that exists separately from all the other molecules. One unit of an ionic compound is a formula unit. A formula unit is a representation of the compound's formula. For example, the formula unit of NaCl is one Na^+1 ion and one Cl^-1 ion. The formula unit of AlCl3 is one Al^+3 ion and three Cl^-1 ions. Ionic compounds don't have separate bundles of atoms like molecular compounds do, so the formula unit is just the smallest number of ions that it takes to represent the formula. </span>
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