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andreyandreev [35.5K]

3 years ago

12

it was believed that earth was a stationary object at the center of the universe all other objects in space without to go around

earth which of these is a criticism of this idea

1 answer:

ehidna [41]3 years ago

8 0

Answer: is that a question or

Explanation:

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Clarify the compounds as strong acid or weak acid<br> HNO3, H2SO4, H2CO3,HCl, HF

Alex777 [14]

Answer:

HNO3 = Strong

H2SO4 = Strong

H2CO3 = Weak

HCl = Strong

HF = Weak

Explanation:

These must be memorized. It's easier to memorize the strong acids as there are fewer of them(7 main ones):

HCl

HBr

HI

HNO3

HClO4

HClO3

H2SO4

7 0

4 years ago

How many grams of cobalt (II) nitrate, Co(NO3)2, are required to make a 2.20%(w/v) aqueous solution in a 250 mL volumetric flask

shutvik [7]

Answer:

$\large \boxed{\text{5.50 g}}$

Explanation:

Percent means " per hundred," so % m/V means the grams of something in 100 mL of volume.

$\text{m/V \%} = \dfrac{\text{mass of solute} }{\text{volume of solution}} \times 100 \, \%$

Data:

m/V % = 2.20 %

V of solution = 250 mL

Calculations:

$\text{2.20 \%} = \dfrac{\text{mass of solute} }{\text{250 mL}} \times 100 \, \%\\\\\text{Mass of solute} = \dfrac{2.20\, \% \times \text{250 mL}}{100 \%} = \text{5.50 g}\\\\\text{The mass of Co(NO$_{3}$)$_{2}$ is $\large \boxed{\textbf{5.50 g}}$}$

8 0

3 years ago

Two balloons are given an electrostatic charge by rubbing them with a wool cloth. Which observation provides evidence of the for

ohaa [14]

Answer:

C. Moving Balloon 1 can make Balloon 2 move without the balloons touching.

Explanation:

When two balloons are rubbed with a wool cloth, they get electrostatic charge and both become negatively charged.

If both balloons will be place close together, balloon 1 will push the balloon 2 far from itself without touching it as they both are negatively charged and things with same charges repel each other.

Hence, the correct answer is "C. Moving Balloon 1 can make Balloon 2 move without the balloons touching."

3 0

3 years ago

Which of the following is a TRUE statement?

belka [17]

Answer:

b

Explanation:

7 0

3 years ago

Read 2 more answers

What is the pH of a solution with a concentration of 5.2 × 10–8 M H3O+?

lora16 [44]

Answer : The pH of a solution is, 7.28

Solution : Given,

Concentration of hydronium ion, $H_3O^+$ = $5.2\times 10^{-8}M$

pH : It is defined as the negative logarithm of hydronium ion concentration or hydrogen ion concentration.

$pH=-\log [H_3O^+]$

Now put the value of hydronium ion concentration in this expression, we get the pH of the solution.

$pH=-\log (5.2\times 10^{-8})=7.28$

Therefore, the pH of a solution is, 7.28

7 0

3 years ago