Answer:
Every element has a proton, neutron, and electron. The number of protons is equal to the atomic number, and the number of electrons is equal to the protons unless it is an ion.
The answer is:
a. 0.712 M
b. 0.210 M
c. 0.336 M
Molarity is a measure of the concentration of solute in a solution.
It can be expressed as moles of solute ÷ volume of solution:
c = n ÷V
where:
c - concentration of solute,
n - moles of solute
V - volume of solution
n can be expressed as:
<span>n = m ÷ Mr
</span>where:
<span>n - moles of solute
</span>m - mass of solute
Mr - relative molecular mass
a. We know volume:
V = 289.2 mL = 0.2892 L
We need n and c.
n = m ÷ Mr
m = 15.4 g
Mr (<span>KCl) = 74.55 g/mol
n = </span>15.4 g ÷ <span>74.55 g/mol
n = 0.206 mol</span>
Thus,
c = 0.206 mol ÷ <span>0.2892 L
c = 0.712 mol/L = 0.712 M
</span>b. We know volume:
V = 0.614 L
We need n and c.
n = m ÷ Mr
m = 14.4 g
Mr (CaCl₂<span>) = 110.98 g/mol
n = </span>14.4 g ÷ <span>110.98 g/mol
n = 0.129 mol</span>
Thus,
c = 0.129 mol ÷ <span>0.614 L
c = 0.210 mol/L = 0.210 M
</span>
c. We can use formula:
m₁V₁ = m₂V₂
<span>m₁ = 3 M
</span><span>V₁ = 28 mL= 0.028 L
</span><span>m₂ = ?
</span><span>V₂ = 0.250 L
</span>Thus:
3 M × 0.028 L = m₂× <span>0.250 L
</span> m₂ = 0.336 M
Answer:
Metal is copper.
Explanation:
Mass of a metal, m = 54 g
Heat energy required, Q = 773 J
The temperature changes from 63.0 °C to 100.0 °C.
We need to identify the metal. Heat required to raise the temperature is given by :
c is specific heat of the metal
We can identify the metal by finding its specific heat.
The metal is copper. Its specific heat is 
.
<span>The answer is C.) Layer A is the stratosphere and Layer B is the troposphere.
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