Answer:
D
Explanation:
Question: Scientists can use many strategies during investigations, including heldwork, surveys,
models, and experiments. Which of these phrases best describes an experiment?
A mathematical analysis of data
B. observation of animals in their natural world
Ci collection of data from an uncontrolled environment for comparative purposes
D. procedure with controlled conditions and test and outcome variables
Answer:
Explanation:
From the statement of the problem,
B₂S₃ + H₂O → H₃BO₃ + H₂S
B₂S₃ + H₂O → H₃BO₃ + H₂S
We that the above expression does not conform with the law of conservation of mass:
To obey the law, we need to derive a balanced reaction equation:
Let us use the mathematical method to obtain a balanced equation.
let the balanced equation be:
aB₂S₃ + bH₂O → cH₃BO₃ + dH₂S
where a, b, c and d will make the equation balanced.
Conservating B: 2a = c
S: 3a = d
H: 2b = 3c + 2d
O: b = 3c
if a = 1,
c = 2,
b = 6,
2d = 2(6) - 3(2) = 6, d = 3
Now we can input this into our equation:
B₂S₃ + 6H₂O → 2H₃BO₃ + 3H₂S
B₂S₃ + 6H₂O → 2H₃BO₃ + 3H₂S
So, the question would would probably ask if the gold ring is indeed pure gold. Let's calculate the specific heat capacity of the calorimeter. If this is equal to the given specific heat for pure gold, then the the gold ring is pure gold.
Qwater = mCdT = (50 g)(4.18 J/gC)(31 - 23.7) = 1525.7 J
Through conservation of energy,
Qwater = Qcalorimeter = mCdT = 1525.7
1525.7 = (10.5)(C)(78.3 - 31)
Solving for C,
C = 3.072 J/gC
Since the specific heat of the calorimeter is not equal to that of the pure gold (0.1291 J/gC), then the gold ring is not pure.
Answer:
Positively Charged
Explanation:
The is a group XVI and period 4 element of the periodic table with similar physical and chemical to that of tellurium and sulfur. Selenium exist in different allotropic forms, which have different solubility including selenate, selenite and selenium in elemental form
The Se ion in selenate has a positive charge of +6, while the selenate ion has a charge of -2
The Se ion in selenite has a charge of +4, while the selenite ion has a negative charge of -2.
The charge of Se in elemental selenium is 0.