Answer:
Physical evidence is any and all objects that can establish that a crime has been committed or can provide a link between a crime and its victim or perpetrator. ... Physical evidence aids in the solution of a case, provides an element of the crime, such as fear or force, and proves a theory in the case.
Explanation:
Answer:
Na₂SO₄
Explanation:
Assume that you have 100 g of the compound.
Then you have 32.37 g Na, 22.57 g S, and 45.05 g O.
1. Calculate the moles of each element.
Moles of Na = 32.37 × 1/22.99 = 1.408 mol Na
Moles of S = 22.57 × 1/32.06 = 0.7040 mol S
Moles of O = 45.05 × 1/16.00 = 2.816 mol O
2. Calculate the <em>molar ratio</em>s.
Divide all values by the smallest number.
Na: 1.408/0.7040 = 2.000
S: 0.7040/0.7040 = 1
O: 2.816/0.7040 = 4.000
3. Determine the empirical formula
Round off all numbers to the closest integer.
Na: 2
S: 1
O: 4
The empirical formula is Na₂SO₄.
Answer:
E) C₂H₄(g) + H₂(g) ⇒ C₂H₆(g)
Explanation:
Which ONE of the following is an oxidation–reduction reaction?
A) PbCO₃(s) + 2 HNO₃(aq) ⇒ Pb(NO₃)₂(aq) + CO₂(g) + H₂O(l). NO. All the elements keep the same oxidation numbers.
B) Na₂O(s) + H₂O(l) ⇒ 2 NaOH(aq). NO. All the elements keep the same oxidation numbers.
C) SO₃(g) + H₂O(l) ⇒ H₂SO₄(aq). NO. All the elements keep the same oxidation numbers.
D) CO₂(g) + H₂O(l) ⇒ H₂CO₃(aq). NO. All the elements keep the same oxidation numbers.
E) C₂H₄(g) + H₂(g) ⇒ C₂H₆(g). YES. <u>C is reduced</u> and <u>H is oxidized</u>.
Answer:
By conducting a chemical reaction.
Explanation:
To form a new substance from old ones, you have to allow the old substances to react with each other, forming something different.