Answer:
C. making models
Explanation:
Making models facilitates constructing depictions of complex objects or practices that enable students to practice and understand how things work which can not be observed and measured directly. Model making needs abstract thinking about the tools and material used, spatial thinking, and well-organized idea of the project to create complex objects.
Answer:
Lavoisier reacted mercury with oxygen to form mercuric oxide
Answer:
0.10M of Ba²⁺ is the concentration of the metal in excess
Explanation:
Based on the chemical reaction:
K₂CO₃(aq) + Ba(NO₃)₂(aq) → BaCO₃(s) + 2KNO₃(aq)
<em>1 mole of potassium carbonate reacts per mole of barium nitrate</em>
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To solve this question we need to find the moles of each salt to find then the moles of Barium in excess:
<em>Moles K₂CO₃:</em>
0.025L * (0.25mol / L) = 0.00625moles K₂CO₃ = moles CO₃²⁻
<em>Moles Ba(NO₃)₂:</em>
0.030L * (0.40mol/L) = 0.012 moles of Ba(NO₃)₂ = 0.012 moles of Ba²⁺
That means moles of Ba²⁺ that don't react are:
0.012 mol - 0.00625mol = 0.00575 moles Ba²⁺
In 25 + 30mL = 55mL:
0.00575 moles Ba²⁺ / 0.055L =
<h3>0.10M of Ba²⁺ is the concentration of the metal in excess</h3>
Answer:
3557J is the heat lost by the water
Explanation:
Using the equation:
Q = m*C*ΔT
<em>Where Q is change in heat</em>
<em>m is mass of substance (23g of water)</em>
<em>C is specific heat of the substance (4.18J/g°C)</em>
<em>And ΔT is change in temperature (68.0°C - 31.0°C = 37.0°C)</em>
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we can find the amount of heat lost as follows:
Q = 23g*4.18J/g°C*37°C
Q =
3557J is the heat lost by the water
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