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monitta
3 years ago
8

What is the mass of 4.95 x 10^21 platinum atoms?

Chemistry
1 answer:
Allisa [31]3 years ago
6 0
28.............................

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How many grams of H3PO4 are in 175mL of a 2.50M solution of H3PO4?
solmaris [256]
<span>(0.1875 moles)(98.004 g/mole) = 18.37575 g </span>
<span>In correct number of significant figures: 18.4 </span>
5 0
3 years ago
Read 2 more answers
You could add aquous hydrochloric to the solution to precipitate out silver chloride. What volume of a 0.130 M aqueous hydrochlo
Mila [183]
1) Chemical reaction: AgNO₃ + HCl → AgCl + HNO₃.
V(AgNO₃) = 30,0 mL = 0,03 L.
c(AgNO₃) = 0,225 mol/L.
n(AgNO₃) = 0,03 L · 0,225 mol/L.
n(AgNO₃) = 0,00675 mol.
From chemical reaction: n(AgNO₃) : n(HCl) = 1 : 1.
0,00675 mol : n(HCl) = 1 : 1.
n(HCl) = 0,00675 mol.
V(HCl) = n(HCl) ÷ c(HCl).
V(HCl) = 0,00675 mol ÷ 0,130 mol/L.
V(HCl) = 0,0519 L = 51,92 ml.

2) 1) Chemical reaction: AgNO₃ + KCl → AgCl + KNO₃.
V(AgNO₃) = 30,0 mL = 0,03 L.
c(AgNO₃) = 0,225 mol/L.
n(AgNO₃) = 0,03 L · 0,225 mol/L.
n(AgNO₃) = 0,00675 mol.
From chemical reaction: n(AgNO₃) : n(KCl) = 1 : 1.
0,00675 mol : n(KCl) = 1 : 1.
n(KCl) = 0,00675 mol.
m(KCl) = n(KCl) · M(KCl).
m(KCl) = 0,00675 mol · 74,55 g/mol.
m(KCl) = 0,503 g.
n - amount of substance.
M - molar mass.
5 0
3 years ago
A gas at 928 kpa, 129 C occupies a volume of 569 L. Calculate the volume at 319 kpa and<br> 32 C.
lisabon 2012 [21]

Answer:

1255.4L

Explanation:

Given parameters:

P₁  = 928kpa

T₁  = 129°C

V₁  = 569L

P₂ = 319kpa

T₂  = 32°C

Unknown:

V₂  = ?

Solution:

The combined gas law application to this problem can help us solve it. It is mathematically expressed as;

           \frac{P_{1} V_{1} }{T_{1} }   = \frac{P_{2} V_{2} }{T_{2} }

P, V and T are pressure, volume and temperature

where 1 and 2 are initial and final states.

Now,

 take the units to the appropriate ones;

             kpa to atm,  °C to K

P₂ = 319kpa in atm gives 3.15atm

P₁  = 928kpa gives 9.16atm

T₂  = 32°C gives 273 + 32  = 305K

T₁  = 129°C gives 129 + 273  = 402K

Input the values in the equation and solve for V₂;

        \frac{9.16  x 569}{402}   = \frac{3.15 x V_{2} }{305}

       V₂   = 1255.4L

4 0
3 years ago
13. What is the symbol for Enthalpy change?
OverLord2011 [107]

Answer:

Explanation:

13 ) symbol of enthalpy change = Δ H .

14 ) enthalpy change is nothing but heat absorbed or evolved .

During fusion enthalpy change

Δ H .= m Lf , m is mass and Ls is latent heat of fusion

During evaporation, enthalpy change

Δ H .= m Lv , m is mass and Lv is latent heat of evaporation

during temperature rise , enthalpy  change

Δ H = m c Δ T

In case of gas , enthalpy change can be calculated by the following relation

Δ H = Δ E + W , Δ E is change in internal energy , W is work done by gas.

15 ) When enthalpy change is negative , that means heat is released to the environment .So reaction is called exothermic .

when heat is absorbed enthalpy change is positive . Reaction is endothermic.

5 0
3 years ago
The chemical process of photosynthesis is one that requires a constant supply of energy to proceed; in this
astra-53 [7]

Answer:-

pls find the answer in description

Explanation:

if u are here u are a fool for shure

4 0
3 years ago
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