Answer:
When zinc is added to copper sulphate (CUSO4) solution due to more reactivity of zinc, cooper is replaced by the zinc and forms zinc sulphate. During the process, the colour of the solution changes from blue to colourless.
Answer:
0.718L of 0.81M HCl are required
Explanation:
Based on the reaction:
Cd(s)+2HCI(aq) → H2(g)+CdCl2(aq)
<em>1 mol of Cd reacts with 2 moles of HCl</em>
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To solve this question we must, as first, find the moles of Cd. With the moles of Cd we can find the moles of HCl needed to react completely with the Cd. With the moles and the molarity we can find the volume:
<em>Moles Cd -Molar mass: 112.411g/mol-:</em>
32.71g * (1mol / 112.411g) = 0.2910 moles Cd
<em>Moles HCl:</em>
0.2910 moles Cd * (2 moles HCl / 1mol Cd) =
0.5820 moles HCl
<em>Volume:</em>
0.5820 moles HCl * (1L / 0.81moles) =
<h3>0.718L of 0.81M HCl are required</h3>
Answer:1. Energy 2. Medium 3. Original position 4. Waves 5. Matter
Explanation:
Answer:
2H⁺(aq) + Sr(OH)₂(s) ⟶ Sr²⁺(aq) + 2H₂O(ℓ)
Explanation:
You aren't dumb. You just need more time to learn the concepts.
There are three steps you must follow. You must write the:
- Molecular equation
- Ionic equation
- Net ionic equation
1. Molecular equation
2HBr + Sr(OH)₂ ⟶ SrBr₂ + 2H₂O
To predict the states of the substances, we must remember some solubility rules:
- HBr is a strong acid. It dissociates completely in water.
- Most hydroxides are only slightly soluble. Unless the solution is quite dilute, I would write their states in water as "(s)", i.e., a suspension of the solid in water.
- Salts containing Br⁻ are generally soluble.
Acids and bases react to give salts and water.
Thus, the molecular equation is
2HBr(aq) + Sr(OH)₂(s) ⟶ SrBr₂(aq) + 2H₂O(ℓ)
B. Ionic equation
You write all the soluble substances as ions.
2H⁺(aq)+ 2Br⁻(aq) + Sr(OH)₂(s) ⟶ Sr²⁺(aq) + 2Br⁻(aq) + 2H₂O(ℓ)
C. Net ionic equation
To get the net ionic equation, you cancel the ions that appear on each side of the ionic equation.
2H⁺(aq) + <u>2Br⁻(aq)</u> + Sr(OH)₂(s) ⟶ Sr²⁺(aq) + <u>2Br⁻(aq)</u> + 2H₂O(ℓ)
The net ionic equation is
2H⁺(aq) + Sr(OH)₂(s) ⟶ Sr²⁺(aq) + 2H₂O(ℓ)
<h2>Answer:</h2>
This is a physical change.
<h3>
Explanation:</h3>
Hot asphalt is mixed with the sand crushed stones and spread onto the roads, when it gets dry it becomes hard giving a smooth straight surface of the road.
Asphalt is used to stick together stones and sand in the road.
It is a physical change because the phase of the asphalt changed from the liquid to solid.
At high temperature, asphalt is in liquid form and at room temperature, it is present in hard solid form.
