If an atom has an atomic mass of 14 and has 6 protons, how many neutrons does the atom have?

Hard water often contains dissolved Ca2+ and Mg2+ ions. One way to soften water is to add phosphates. The phosphate ion forms in

katrin2010 [14]

Answer:

$22.4269$ grams of sodium phosphate must be added to 1.4 L of this solution to completely eliminate the hard water ions

Explanation:

We will first write the balanced equation for this scenario

3 CaCl2 + 2 Na3PO4 ----> 6 NaCl + Ca3 (PO4)2

3 Mg(NO3)2 + 2 Na3PO4 -----> 6 NaNO3 + Mg3 (PO4)2

The ratio here for both calcium chloride and magnesium nitrate is $3:2$

The number of moles of each compound is equal to

$0.054 * 1.4 = 0.0756\\0.093* 1.4 = 0.1302$

Using the mole ratio of 3:2, convert each to moles of sodium phosphate.

$0.0756$ mole of CaCl2 is equal to $0.05\\$ Na3PO4

$0.1302$ mole of CaCl2 is equal to $0.0868$ Na3PO4

Converting moles of sodium phosphate to grams of sodium phosphate we get

$(0.05 +0.0868) * 163.94$ g/mol

$22.4269$ grams of sodium phosphate must be added to 1.4 L of this solution to completely eliminate the hard water ions

8 0

3 years ago

The absorbance (????)(A) of a solution is defined as ????=log10(????0????) A=log10⁡(I0I) where ????0I0 is the incident‑light int

bulgar [2K]

Answer:

The absorbance of the myoglobin solution across a 1 cm path is 0.84.

Explanation:

Beer-Lambert's law :

Formula used :

$A=\epsilon \times c\times l$

$A=\log \frac{I_o}{I}$

$\log \frac{I_o}{I}=\epsilon \times c\times l$

where,

A = absorbance of solution

c = concentration of solution

$\epsilon$ = Molar absorption coefficient

l = path length

$I_o$ = incident light

$I$ = transmitted light

Given :

l = 1 cm, c = 1 mg/mL , $\epsilon = 15,000 M^{-1}cm^{-1}$

Molar mass of myoglobin = 17.8 kDa = 17.8 kg/mol=17800 g/mol

(1 Da = 1 g/mol)

c = 1 mg /mL = ${1mg /mL}{\text{Molar mass of myoglobin}}$

$c = \frac{1 mg/mL}{ 17800 g/mol} = 5.6179\times 10^{-5} mol/L$

1 mg = 0.001 g, 1 mL = 0.001 L

$A= 15,000 M^{-1}cm^{-1}\times 5.6179\times 10^{-5} mol/L\times 1 cm$

$A=0.8426 \approx 0.84$

The absorbance of the myoglobin solution across a 1 cm path is 0.84.

5 0

3 years ago

Consider three gases: Ar, SF6, and Cl2. If 50.0 grams of these gases are placed in each of three identical containers, which con

adoni [48]

The ideal gas law:
$pV=nRT \Rightarrow p=\frac{nRT}{V}$
p - pressure, n - number of moles, R - the gas constant, T - temperature, V - volume

The volume and temperature of all three containers are the same, so the pressure depends on the number of moles. The greater the number of moles, the higher the pressure.
The mass of gases is 50 g.

$Ar \\
M \approx 39.948 \ \frac{g}{mol} \\
n=\frac{50 \ g}{39.948 \ \frac{g}{mol}} \approx 1.25 \ mol \\ \\
SF_6 \\
M \approx 146.06 \ \frac{g}{mol} \\
n=\frac{50 \ g}{146.06 \ \frac{g}{mol}} \approx 0.34 \ mol \\ \\
Cl_2 \\
M=70.9 \ \frac{g}{mol} \\
n=\frac{50 \ g}{70.9 \ \frac{g}{mol}} \approx 0.71 \ mol$

The greatest number of moles is in the container with Ar, so there is the highest pressure.

4 0

3 years ago

The ph of water is _____ because it contains an equal amount of h and oh- ions.

gtnhenbr [62]

The PH of water is 7 because it contains an equal amount of h and oh- ions.

6 0

3 years ago

the trunk of a certain tree is 50 cm thick. Each year it gets thicker by 1 cm. How thick will the tree trunk be in 50 years

Mama L [17]

100 centimeters thick

Starting thickness was 50 cm
1 cm every 50 years= 1x50
1x50=50
Old thickness + New thickness= 50 + 50 = 100 cm
:)

5 0

3 years ago