# Tutor profile: Rupanshi M.

## Questions

### Subject: Basic Chemistry

1. How many grams of Oxygen is needed to react completely with 30g of Aluminum?

A question like this involves an understanding of two main concepts of Chemistry and some basic math: 1. Writing chemical equations 2. Balancing equations 3. Basic math 1. Let's start from Step 1 To write this chemical equation, you first need to know the chemical symbols of Aluminum (Al) and Oxygen (O2)*. Remember oxygen is diatomic. Then focus on the predicting the product. To predict the product, you need to know the common charge of both these atoms. For Al, it's 3+ and for O2*, it's 2-. So, when a product is formed, these charges will become the subscripts for the other atom. Like this: Al2O3* Chemical equation: O2* + Al = Al2O3* 2. Let's move on to Step 2 To balance this equation, balance the Aluminum first. We have 2 moles of Al on the right side of the equation so if we put 2 in front of Al on the left side of the equation, Al is balanced on both sides. Then move on to O2*. We have 2 moles of it on the left side and 3 moles of it on the right side. In order to balance this out, we need to find the least common multiple of 2 and 3, which is 6. Or simply put, multiply left side by 2 and the right side by 3. By doing this, we have 4 moles of Al on the right side. To balance this out, multiply the left side by 4 as well for Al. Balanced Chemical equation: 3O2* + 4Al = 2Al2O3* 3. Now that we have our balanced equation, We know that 4 moles of Al reacts with 3 moles of oxygen. We also know that weight of Al is 27 and that of O2* is 32 (diatomic) from the periodic table. So, now we can start solving... Focus on units to cancel them out: 30 g Al x (1 mol of Al/ 27g of Al) x (3 mol 02* / 4 mol of Al) x ( 32 g 02*/ 1 mol 02*)= 26.67 g *= for the atoms with this asterisk, the numbers are supposed to be in the subscript

### Subject: Biology

1. How are identical twins formed in the womb?

There are two ways by which identical twins (Scientific term: monozygotic twins) can be formed: 1. One egg is fertilized by one sperm resulting in a zygote. If the zygote splits into 2, identical twins are formed. 2. For some people, it's hard to conceive naturally for many reasons. However, we have a lot of technology and knowledge to help with that now. The mother can opt for fertility treatments and have a fertilized egg transferred to her uterus. If that fertilized egg splits into two in her uterus, identical twins are formed. Just for some knowledge, fraternal twins (Scientific term: dizygotic twins) are formed when two separate eggs are fertilized by two separate sperms.

### Subject: Algebra

1. Find x by solving the following equation: 6x-4=2x-2

1. To solve a problem like this, pay attention to what the question is asking for. It's asking to find x. 2. To find x, rearrange the equation to collect like terms on the same side of the equation. Make sure to flip the sign (+/-) when you move them from one side to the other. Like this: 6x-2x= -2+4 3. Solve the equation further until there is only 1 term left on each side of the equation. Like this: 4x= 2 4. To isolate x, divide both sides by 4. Like this: 4x/4= 2/4 5. Do the math and find x. Like this: x= 1/2

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