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andrey2020 [161]

2 years ago

14

Which statement is true? Postively charged objects attract other positively charged objects negatively charged objects attract o

ther negatively charged objects

1 answer:

ANEK [815]2 years ago

8 0

Answer:

Explanation:one is true because if it is positiveit would not be attracting it would be sepperating

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The carbon dioxide exhaled by astronauts can be removed from a spacecraft by reacting it with lithium hydroxide (LiOH). The reac

maks197457 [2]

Two astronauts would exhale about 40 moles of carbon dioxide daily.

Carbon dioxide reacts with lithium hydroxide in a 1 : 2 mole ratio. Set up a proportion:

1 : 2 = 40 : x

Then, find x: <span>12=40x

</span> Cross multiply. x = 80 moles of LiOH per day for both astronauts

8 0

3 years ago

Which group 1 metal and group 2 non metal would react together most?

Talja [164]

Answer:

Potassium and oxygen

Explanation:

3 0

2 years ago

In addition to decreasing the amount of fat in a dish, salsa can also increase the amount of

morpeh [17]

Its c ok im sorry if i got the last answer wrong

4 0

3 years ago

How do we balance Zn + HNO3 Zn(NO3)2 + NO + H20

USPshnik [31]

3Zn + 8HNO₃⇒ 3Zn(NO₃)₂ + 2NO + 4H₂O

<h3>Further explanation </h3>

Equalization of chemical reaction equations can be done using variables. Steps in equalizing the reaction equation:

1. gives a coefficient on substances involved in the equation of reaction such as a, b, or c etc.

2. make an equation based on the similarity of the number of atoms where the number of atoms = coefficient × index between reactant and product

3. Select the coefficient of the substance with the most complex chemical formula equal to 1

For gas combustion reaction which is a reaction of hydrocarbons with oxygen produces CO₂ and H₂O (water vapor). can use steps:

Balancing C atoms, H and the last O atoms

Reaction

Zn + HNO₃⇒ Zn(NO₃)₂ + NO + H₂O

1. gives a coefficient

aZn + bHNO₃⇒ Zn(NO₃)₂ + cNO + dH₂O

2. make an equation

Zn : left = a, right =1 ⇒a=1

H : left = b, right = 2d⇒ b=2d (eq 1)

N : left = b, right = 2+c⇒b=2+c (eq 2)

O : left = 3b, right = 6+c+d ⇒3b=6+c+d(eq 3)

From eq 1 and eq 3

3(2d)=6+c+d

6d=6+c+d

5d=6+c (eq 4)

From eq 2 and eq 3

3(2+c)=6+c+d

6+3c=6+c+d

2c=d (eq 5)

From eq 4 and eq 5

5(2c)=6+c

10c=6+c

9c=6

c = 2/3

input eq 5

d = 2 x 2/3

d = 4/3

input eq 1

b = 2 x 4/3

b = 8/3

The equation

aZn + bHNO₃⇒ Zn(NO₃)₂ + cNO + dH₂O to

Zn + 8/3HNO₃⇒ Zn(NO₃)₂ + 2/3NO + 4/3H₂O x 3

3Zn + 8HNO₃⇒ 3Zn(NO₃)₂ + 2NO + 4H₂O

8 0

3 years ago

Exactly how much time must elapse before 16 grams of potassium-42decays, leaving 2 grams of the original isotope?(1) 8 × 12.4 ho

AleksandrR [38]

The answer is <span>(3) 3 × 12.4 hours
</span>
To calculate this, we will use two equations:
$(1/2) ^{n} =x$
$t_{1/2} = \frac{t}{n}$
where:
<span>n - number of half-lives
</span>x - remained amount of the sample, in decimals
<span> $t_{1/2}$ - half-life length
</span>t - total time elapsed.

First, we have to calculate x and n. x is <span>remained amount of the sample, so if at the beginning were 16 grams of potassium-42, and now it remained 2 grams, then x is:
2 grams : x % = 16 grams : 100 %
x = 2 grams </span>× 100 percent ÷ 16 grams
x = 12.5% = 0.125

Thus:
<span> $(1/2) ^{n} =x$
</span> $(0.5) ^{n} =0.125$
$n*log(0.5)=log(0.125)$
$n= \frac{log(0.5)}{log(0.125)}$
$n=3$

It is known that the half-life of potassium-42 is 12.36 ≈ 12.4 hours.
Thus:
<span> $t_{1/2} = 12.4$
</span><span> $t_{1/2} *n = t$
</span> $t= 12.4*3$

Therefore, it must elapse 3 × 12.4 hours <span>before 16 grams of potassium-42 decays, leaving 2 grams of the original isotope</span>

7 0

3 years ago

Read 2 more answers