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2 years ago

15

Hi! I wanted to know what my grade would be for my test. There are 23 questions in total. 2 of the 23 questions are essay questi

ons that are worth 4 points each. I got two questions wrong that were worth 1 point each. Thank you!!

1 answer:

kolbaska11 [484]2 years ago

6 0

Answer:

high B or a low A:) Good Luck

Explanation:

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the most common source of copper (Cu) is the mineral chalcopyrite (CuFeS2). How many kilograms of chalcopyrite must be mined to

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<span>0.650 kg... I think,
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3 years ago

Plz answer ASAP

strojnjashka [21]

Answer:

this should help *not a virus

Explanation:

https://kidshealth.org/en/teens/digestive-system.html

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2 years ago

What happens to a charged particle that enters a magnetic field?

attashe74 [19]

Answer:

A charged particle experiences a force when moving through a magnetic field. ... If the field is in a vacuum, the magnetic field is the dominant factor determining the motion. Since the magnetic force is perpendicular to the direction of travel, a charged particle follows a curved path in a magnetic field. i hope this helped you! have a great day

Explanation:

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2 years ago

What is the pH of a mixture of 0.042 M NaH2PO4 and 0.058 M Na2HPO4? Hint: The pKa of phosphate is 6.86.

AlekseyPX

Answer:

The pH value of the mixture will be 7.00

Explanation:

Mono and disodium hydrogen phosphate mixture act as a buffer to maintain pH value around 7. Henderson–Hasselbalch equation is used to determine the pH value of a buffer mixture, which is mathematically expressed as,

$pH=pK_{a} + log(\frac{[Base]}{[Acid]})$

According to the given conditions, the equation will become as follow

$pH=pK_{a} + log(\frac{[Na_{2}HPO_{4} ]}{[NaH_{2}PO_{4}]})$

The base and acid are assigned by observing the pKa values of both the compounds; smaller value means more acidic. NaH₂PO₄ has a pKa value of 6.86, while Na₂HPO₄ has a pKa value of 12.32 (not given, but it's a constant). Another more easy way is to the count the acidic hydrogen in the molecular formula; the compound with more acidic hydrogens will be assigned acidic and vice versa.

Placing all the given data we obtain,

$pH=6.86 + log(\frac{0.058}{0.042})$

$pH=7.00$

5 0

3 years ago

A solid with a mass of Mgrams is melted by heating it. After a half-hour, the solid is

Lerok [7]

Answer:

equal to M

Explanation:

The mass of the fully melted mass and the initial solid will be the same. So, the mass of the melt is equal to M.

Mass is the amount of matter contained within a substance. Since only the phase changed and the amount of matter is still the same, the mass of the molten phase and the solid phase will remain the same.

We are correct to say that in the heating process no mass was destroyed or added in melting the solid.

A simple phase change that preserved the mass only occurred.

7 0

2 years ago