Which of these elements has four valence electrons

15.5 g of an unknown metal at 165.0°C is dropped into 150.0mL of H2O at 23.0°C in a coffee cup calorimeter. The metal and H2O re

tino4ka555 [31]

Answer:

Specific heat capacity of metal is 2.09 j/g.°C.

Explanation:

Specific heat capacity:

It is the amount of heat required to raise the temperature of one gram of substance by one degree.

Formula:

Q = m.c. ΔT

Q = amount of heat absorbed or released

m = mass of given substance

c = specific heat capacity of substance

ΔT = change in temperature

Given data:

Mass of metal = 15.5 g

Initial temperature = 165.0°C

Initial temperature of water = 23.0°C

Final temperature = 30.0°C

Specific heat capacity of metal = ?

Specific heat capacity of water = 4.184 J/g°C

Volume of water = 150.0 mL or 150.0 g

Solution:

Formula:

- Qm = +Qw

Now we will put the values in formula.

-15.5 g × c × [ 30.0°C - 165.0°C] = 150 g × 4.184 J/g°C × [ 30.0°C - 23.0°C]

15.5 g × c × 135°C = 4393.2 j

2092.5 g.°C × c = 4393.2 j

c = 4393.2 j/2092.5 g.°C

c = 2.09 j/g.°C

4 0

2 years ago

david’s mom wants to calculate how much it will cost to drive from los angeles, ca, to san francisco, ca. gas costs $4.00 a gall

grin007 [14]

She needs to know the distance from LA to SF.

Call that distance x. Then you can calculate the cost from:

# of gallons consumed: x miles / 38 miles/ gallon = (x/38) gallons

After that,

cost = # gallons * cost per gallon = (x/38) gallons * 4 $/gallon = 4x/38 $

3 0

3 years ago

Read 2 more answers

Which is the smallest particle into which water (H2O) in a glass can be broken down and still remain water? A. a water molecule

Gnesinka [82]

Answer:-

A. A water molecule

Explanation:-

A molecule is the smallest particle of a compound that retains all it's chemical properties.

Here H2O is a compound. So the smallest particle that will retain all the chemical properties and still remain water is water molecule.

Atoms Hydrogen and Oxygen both have different chemical properties from water H2O and are thus different.

Hydrogen peroxide is different molecule from water. So it is also not water.

6 0

3 years ago

Read 2 more answers

A solution is made by mixing of water and of acetic acid . Calculate the mole fraction of water in this solution. Be sure your a

Molodets [167]

Answer:

The answer is "0.35".

Explanation:

please find the complete question in the attached file.

Mass of $CH_3C0_2 H$ $= 77 \ g \\\\$

Molar mass of $CH_3C0_2 H$ $= 60.05 \ \frac{g}{mol} \\\\$

No of moles in $n_{CH_3CO_2H}$ $= 77 \ g \times \frac{1 \ mol \ CH_3C0_2H}{60.05 \ g}$

$= 1.28 \ mol \ CH_3CO_2H$

Mass of water $(H_2O)$ $= 42 \ g$

The molar mass of water $(H_2O)$ $= 18.02 \ \frac{g}{mol}$

moles of water $n_{H_2O}$ :

$= 42 \ g \times \frac{1 mol H_2O}{18.02 \ g} \\\\= 2.33 \ mol \ H_2 O$

Molfraction of acetic acid:

$X CH_2CO_2H = \frac{n_{CH_3CO_2H}}{n_CH_3CO_2H +n_{H_2}}\\\\$

$=\frac{1.28 \ mol}{1.28 \ mo1 + 2.33 mol}\\\\ = 0.354\\\\= 0.35$

7 0

2 years ago

Limestone (CaCO₃) is the second most abundant mineral on Earth after SiO₂. For many uses, it is first decomposed thermally to qu

steposvetlana [31]

Limestone (CaCO₃) is the second most abundant mineral on Earth after SiO₂. For many uses, it is first decomposed thermally to quicklime (CaO). MgO is prepared similarly from MgCO₃.

AT 871°C CaCO 3 needs about 1 hour for complete decomposition.

<h3>At what temperature Caco3 decompose to Cao?</h3>

At any temperature higher than 835°C, the value of Δ G ∘ will be negative and the decomposition reaction will be spontaneous.

AT 871°C CaCO 3 needs about 1 hour for complete decomposition.

Calcium carbonate decomposes on heating to give calcium oxide and carbon dioxide.

To learn more about Caco3, refer

brainly.com/question/26187973

#SPJ4

5 0

1 year ago